Information

10.1: Atmospheric Pollution - Biology


Air pollution occurs in many forms but can generally be thought of as gaseous and particulate contaminants that are present in the earth’s atmosphere. Chemicals discharged into the air that have a direct impact on the environment are called primary pollutants. These primary pollutants sometimes react with other chemicals in the air to produce secondary pollutants.

Air pollution is typically separated into two categories: outdoor air pollution and indoor air pollution. Outdoor air pollution involves exposures that take place outside of the built environment. Examples include fine particles produced by the burning of coal, noxious gases such as sulfur dioxide, nitrogen oxides and carbon monoxide; ground-level ozone and tobacco smoke. Indoor air pollution involves exposures to particulates, carbon oxides, and other pollutants carried by indoor air or dust. Examples include household products and chemicals, out-gassing of building materials, allergens (cockroach and mouse dropping, mold, pollen), and tobacco smoke.

Sources of Air Pollution

A stationary source of air pollution refers to an emission source that does not move, also known as a point source. Stationary sources include factories, power plants, and dry cleaners. The term area source is used to describe many small sources of air pollution located together whose individual emissions may be below thresholds of concern, but whose collective emissions can be significant. Residential wood burners are a good example of a small source, but when combined with many other small sources, they can contribute to local and regional air pollution levels. Area sources can also be thought of as non-point sources, such as construction of housing developments, dry lake beds, and landfills.

A mobile source of air pollution refers to a source that is capable of moving under its own power. In general, mobile sources imply “on-road” transportation, which includes vehicles such as cars, sport utility vehicles, and buses. In addition, there is also a “non-road” or “off-road” category that includes gas-powered lawn tools and mowers, farm and construction equipment, recreational vehicles, boats, planes, and trains.

Agricultural sources arise from operations that raise animals and grow crops, which can generate emissions of gases and particulate matter. For example, animals confined to a barn or restricted area produce large amounts of manure. Manure emits various gases, particularly ammonia into the air. This ammonia can be emitted from the animal houses, manure storage areas, or from the land after the manure is applied. In crop production, the misapplication of fertilizers, herbicides, and pesticides can potentially result in aerial drift of these materials and harm may be caused.

Unlike the above mentioned sources of air pollution, air pollution caused by natural sourcesis not caused by people or their activities. An erupting volcano emits particulate matter and gases, forest and prairie fires can emit large quantities of “pollutants”, dust storms can create large amounts of particulate matter, and plants and trees naturally emit volatile organic compounds which can form aerosols that can cause a natural blue haze. Wild animals in their natural habitat are also considered natural sources of “pollution”.

Six Common Air Pollutants

The most commonly found air pollutants are particulate matter, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. These pollutants can harm health and the environment, and cause property damage. Of the six pollutants, particle pollution and ground-level ozone are the most widespread health threats. The U.S. Environmental Protection Agency (EPA) regulates them by developing criteria based on considerations of human and environmental health.

  1. Ground-level ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOC. Breathing ozone can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma. Ground level ozone can also have harmful effects on sensitive vegetation and ecosystems. (Ground-level ozone should not be confused with the ozone layer, which is high in the atmosphere and protects Earth from ultraviolet light; ground-level ozone provides no such protection).
  2. Particulate matter, also known as particle pollution, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.
  3. Carbon monoxide (CO) is a colorless, odorless gas emitted from combustion processes. Nationally and, particularly in urban areas, the majority of CO emissions to ambient air come from mobile sources. CO can cause harmful health effects by reducing oxygen delivery to the body’s organs (like the heart and brain) and tissues. At extremely high levels, CO can cause death.
  4. Nitrogen dioxide (NO2) is one of a group of highly reactive gasses known as “oxides of nitrogen,” or nitrogen oxides (NOx). Other nitrogen oxides include nitrous acid and nitric acid. EPA’s National Ambient Air Quality Standard uses NO2 as the indicator for the larger group of nitrogen oxides. NO2 forms quickly from emissions from cars, trucks and buses, power plants, and off-road equipment. In addition to contributing to the formation of ground-level ozone, and fine particle pollution, NO2 is linked with a number of adverse effects on the respiratory system.
  5. Sulfur dioxide (SO2) is one of a group of highly reactive gasses known as “oxides of sulfur.” The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment. SO2 is linked with a number of adverse effects on the respiratory system.
  6. Lead is a metal found naturally in the environment as well as in manufactured products. The major sources of lead emissions have historically been from fuels in on-road motor vehicles (such as cars and trucks) and industrial sources. As a result of regulatory efforts in the U.S. to remove lead from on-road motor vehicle gasoline, emissions of lead from the transportation sector dramatically declined by 95 percent between 1980 and 1999, and levels of lead in the air decreased by 94 percent between 1980 and 1999. Today, the highest levels of lead in air are usually found near lead smelters. The major sources of lead emissions to the air today are ore and metals processing and piston-engine aircraft operating on leaded aviation gasoline.

Indoor Air Pollution (Major concerns in developed countries)

Most people spend approximately 90 percent of their time indoors. However, the indoor air we breathe in homes and other buildings can be more polluted than outdoor air and can increase the risk of illness. There are many sources of indoor air pollution in homes. They include biological contaminants such as bacteria, molds and pollen, burning of fuels and environmental tobacco smoke, building materials and furnishings, household products, central heating and cooling systems, and outdoor sources. Outdoor air pollution can enter buildings and become a source of indoor air pollution.

Sick building syndrome is a term used to describe situations in which building occupants have health symptoms that are associated only with spending time in that building. Causes of sick building syndrome are believed to include inadequate ventilation, indoor air pollution, and biological contaminants. Usually indoor air quality problems only cause discomfort. Most people feel better as soon as they remove the source of the pollution. Making sure that your building is well-ventilated and getting rid of pollutants can improve the quality of your indoor air.

Secondhand Smoke (Environmental Tobacco Smoke)

Secondhand smoke is the combination of smoke that comes from a cigarette and smoke breathed out by a smoker. When a non-smoker is around someone smoking, they breathe in secondhand smoke.

Secondhand smoke is dangerous to anyone who breathes it in. There is no safe amount of secondhand smoke. It contains over 7,000 harmful chemicals, at least 250 of which are known to damage human health. It can also stay in the air for several hours after somebody smokes. Even breathing secondhand smoke for a short amount of time can hurt your body.

Over time, secondhand smoke can cause serious health issues in non-smokers. The only way to fully protect non-smokers from the dangers of secondhand smoke is to not allow smoking indoors. Separating smokers from nonsmokers (like “no smoking” sections in restaurants)‚ cleaning the air‚ and airing out buildings does not completely get rid of secondhand smoke.

Source: Smokefree.gov


Better understanding air pollution mechanisms

Credit: AAS

Earth's atmosphere has a budget, and when expenses outpace savings, secondary aerosols form in areas of excessive pollution. Greenhouse gases enter the atmosphere, and free radicals bond to the molecules, rendering them inert. But when there are more pollution molecules than free radicals, they are left to recombine and form ozone and visible particulate matter—smog and haze.

The precise mechanisms underlying this atmospheric oxidation capacity are not well understood, leaving the process inadequately described or completely missed in research, according to Wang Yuesi, professor with the State Key Laboratory of Atmospheric Boundary Layer Physics and Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS).

WANG and co-author Liu Zirui, also with LAPC, penned the preface to a special issue of Advances in Atmospheric Sciences (AAS).

"This special issue focuses on the quantification and simulation of atmospheric oxidation capacity processes to better probe the role of missing mechanisms participating in the formation of secondary aerosols," Wang said.

The AAS special issue contains 14 recently published scientific papers investigating atmospheric oxidation capacity processes through various approaches. The papers include field observations of key oxidizing species in different environments, laboratory dynamics studies on ozone formation and more.

WANG co-authored three of the featured papers, including one quantifying the free radical budget and ozone production with numerical modeling. In this study, Wang and his co-authors found that the aerosol uptake of hydrogen superoxide, which consists of a hydrogen and two oxygen atoms, can help break down certain pollutants, essentially expanding the free radical budget by 11% and reducing the daytime ozone production by 14%.

"This suggests the synergetic mechanism of complex air pollution formation is useful for the development of environmental measures," Wang said, noting the work has resulted in a deeper understanding of atmospheric oxidation capacity mechanisms.

He and his team have developed indexes, or indicators, to characterize the atmospheric oxidation capacity in Beijing. Next, they plan to evaluate how the indexes might be applied in other highly polluted regions of China as they further study the relationship between the indexes and air quality.

It is one example of the type of research the special issue highlights and demands more of, according to Wang.

"More in-depth analyses and attributions are still needed for atmospheric oxidation capacity quantification and simulations to further understand the secondary formation processes and improve the underlying mechanisms," Wang said.

Min Xue et al, ROx Budgets and O3 Formation during Summertime at Xianghe Suburban Site in the North China Plain, Advances in Atmospheric Sciences (2021). DOI: 10.1007/s00376-021-0327-4


Abstract

A comprehensive biomonitoring programme should integrate several methods distributed along the biomonitoring chain, allowing to detect exposure, threads and impacts. In the case of a municipal solid waste incinerator (MSWI), biomonitoring of air pollution can contribute to source attribution, detection of ongoing processes and assessment of environmental effects. Three different methods were used to assess the biological effects of air pollution around a MSWI using lichens as biomonitors: (1) lichen diversity (2) bioaccumulation of trace elements and (3) physiological status (photosynthetic efficiency, cell membrane damage, viability). The first method takes into account the native lichen flora, while the other two were applied to thalli of the lichen Evernia prunastri transplanted for 6 months in the study area. Lichen diversity and physiological parameters reflected the effects of air pollution around the incinerator and the surrounding industrial area. High frequencies of non-nitrophilous species corresponded to sites with higher environmental quality, while high frequencies of nitrophilous species corresponded to sites with higher level of eutrophication. Transplanted samples showed increased cell membrane damage and reduced vitality respect to control samples. Bioaccumulation of trace elements pointed at the atmospheric origin of Hg depositions in the area. These results suggest that an integrated use of lichen-based methods along the biomonitoring chain can provide useful biological outputs for decision-makers to establish correct sustainable waste management policies.


1 INTRODUCTION

Developing crops that can be more productive under stressful growing conditions is a high priority for agriculture today, and will be increasingly necessary if we are to avoid production losses to climate change (Challinor et al., 2014 Lesk, Rowhani, & Ramankutty, 2016 Lobell et al., 2014 ). Traditionally, field trials under more extreme environmental conditions than are typical for major crop growing regions have been used to test germplasm developed by breeding or biotechnology. However, some stressors—such as ozone (O3) pollution—are too heterogeneous and unpredictable in time or space to make this approach feasible (Ainsworth, Rogers, & Leakey, 2008 ). In addition, future climate change will result in growing environments with elevated [CO2] and temperature for which there is no present-day analogue (Battisti & Naylor, 2009 Leakey & Lau, 2012 ). Controlled environment growth facilities can provide valuable information on genetic variation in crop responses to stress treatments and the mechanisms underlying genetic variation (Brosché et al., 2010 Burton, Burkey, Carter, Orf, & Cregan, 2016 Frei, Tanaka, & Wissuwa, 2008 Ueda, Siddique, & Frei, 2015 ), but results of such controlled environment experimentation do not always translate into improved performance under production conditions in the field (Ainsworth, Beier, et al., 2008 Araus & Cairns, 2014 McKersie, Bowley, & Jones, 1999 Passioura, 2012 ). Free-air concentration enrichment (FACE) was developed to expose crops under field conditions to elevated concentrations of atmospheric pollutants over the entire growing season, with little or no perturbation to other aspects of the environment (Long, Ainsworth, Rogers, & Ort, 2004 ). But, most FACE experiments have tested a limited number of genotypes, at any given time (Betzelberger et al., 2010 Markelz, Strellner, & Leakey, 2011 Wang et al., 2014 ). Investigation of many genotypes and structured populations is needed to understand the heritability of traits in altered atmospheric environments and ultimately to identify genomic regions and genes associated with O3 tolerance.

Tropospheric O3 is a dynamic, short-lived air pollutant that is estimated to cause annual losses of

10% to US maize yields with crop losses of $7.2 billion (McGrath et al., 2015 ). However, crop yield losses to O3 pollution are not widely recognized by farmers. And, breeding or biotechnology for tolerance to O3 stress has not been a major target for seed companies (Ainsworth, 2017 ). Ozone is formed as a secondary pollutant from nitrogen oxides (NOx) and volatile organic compounds, and recent analyses suggest that progress towards reducing NOx in the United States has slowed considerably, thus increasing the risks of O3 pollution (Jiang et al., 2018 ). Ozone diffuses through stomatal pores on leaf surfaces and reacts to form reactive oxygen species (ROS) in the apoplast. When ROS exceed the antioxidant-quenching capacity of the apoplast, they cause oxidative stress within cells that accelerates senescence and impairs photosynthesis, ultimately reducing plant productivity and crop yields (Ainsworth, Yendrek, Sitch, Collins, & Emberson, 2012 Kangasjärvi, Jaspers, & Kollist, 2005 ). Maize, like many other crop species, is sensitive to O3 damage, and shows accelerated loss of photosynthetic capacity with continued exposure to the air pollutant (Fiscus, Brooker, & Burkey, 2005 Yendrek, Erice, et al., 2017 ). Additionally, stomatal closure can be negatively impacted by O3 stress, leading to excessive water loss under drought stress (Wang et al., 2014 Wilkinson & Davies, 2010 ). Maintenance of high photosynthetic CO2 assimilation without excess stomatal conductance is an important phenotype for increasing O3 tolerance (Ainsworth, 2017 Emberson et al., 2018 ). Furthermore, enhancing photosynthetic CO2 assimilation and water use efficiency (ratio of photosynthetic CO2 assimilation to water loss by transpiration) are widely recognized to be key targets for crop improvement at a time when potential for further gains in harvest index and planting density may be limited (Leakey et al., 2019 Long, Marshall-Colon, & Zhu, 2015 von Caemmerer & Furbank, 2016 ). Despite the importance of maize for food, fuel and animal feed, little is known about the extent or mechanisms of genetic variation in the sensitivity of maize to O3 by comparison to other crops such as soybean, wheat and rice (Betzelberger et al., 2012 Burton et al., 2016 Frei et al., 2008 Wang et al., 2014 ). This represents an important unexplored opportunity because maize is a highly tractable, model system for study of crop genetics (Buckler et al., 2009 Riedelsheimer et al., 2012 Schnable et al., 2009 ).

For physiological performance to be a target for improvement in breeding programmes, there must be underlying additive genetic variation in the traits of interest. The likely success of selection is reflected in the narrow sense heritability, that is, the proportion of phenotypic variation resulting from additive genetic variance (Falconer & Mackay, 1996 Flood, Harbinson, & Aarts, 2011 ). Previous studies of maize have estimated relatively high heritability for traits related to photosynthetic capacity (Cai et al., 2012 Crosbie, Mock, & Pearce, 1977 Lu et al., 2011 Pelleschi et al., 2006 Prado et al., 2017 Wang et al., 2013 Ziyomo & Bernardo, 2013 ) and indicated that variance in photosynthetic traits is mostly additive (Crosbie et al., 1977 ). But, the heritability of photosynthetic traits in crops is reportedly lower under stress conditions (Edwards, Ewers, McClung, Lou, & Weinig, 2012 Pelleschi et al., 2006 ). Prior studies on leaf-level responses to O3 in fescue, potato and sweetcorn found that additive effects (GCA), not dominance effects (SCA), were significant and involved in O3 tolerance (De Vos, Hill, Pell, & Cole, 1982 Johnston, Haaland, & Dickens, 1983 Schraudner, Langebartels, & Sandermann, 1997 ). These studies fumigated crops with very high concentrations of O3 for hours to days, which elicited acute stress responses that are known to be fundamentally distinct from responses to season-long, moderate O3 concentrations that drive yield loss in farmer's fields (Ainsworth et al., 2012 Chen, Frank, & Long, 2009 Schraudner et al., 1997 ). Uncertainty regarding the extent to which photosynthetic traits associated with O3 tolerance are heritable is compounded by the need to know if there are strong genetic correlations across environments (Falconer, 1952 ). In other words, if there is a substantial genotype × environment interaction acting on photosynthetic traits, then selection for crop genotypes than can tolerate elevated O3 pollution would not be successful under standard growing conditions. Alternatively, the absence of genotype × environment interaction would suggest that past selection for highly productive genotypes would likely have incidentally selected for tolerance to O3 pollution as well. In addition, genetic correlations among traits are useful in assessing how many independent traits need to be evaluated for a successful selection index to be developed.

Proof-of-concept is needed to demonstrate the use of FACE experimentation to estimate the heritability of photosynthetic traits and the degree to which elevated O3 affects heritability in a farm-field setting (Frei, 2015 ). Therefore, in this study, we used a half-diallel mating design to test for (a) the effects of elevated O3 on photosynthetic traits in maize (b) the heritability and genetic correlations among photosynthetic traits in maize and (c) the identification of particularly susceptible parental lines.


10 Adverse Effects of Various Water Pollutants | Water Pollution

This article throws light upon the ten adverse effects of various water pollutants. Some of the adverse effects are: 1. Effects of Inorganic Water Pollutants 2. Effects of Organic Water Pollutants 3. Effects of Sewage and Domestic Wastes 4. Effects of Sediments 5. Effects of Synthetic Detergents and Others.

Adverse Effect of Water Pollutant # 1. Effects of Inorganic Water Pollutants:

a. Acidic pollutants are lethal to fish, most invertebrates and micro-organisms at pH below 4.0. Acid mine drainage is the major cause of fish kill.

b. Strong alkalies like NaOH and KOH are known to produce asphyxiation by the coagulation of gill secretions in fish.

c. Excess of inorganic pollutants like CO 2- 3, SO 2- 4 , Ca 2+ , Mg 2+ make the water hard and unsuitable for boilers.

d. Soluble salts not only affect aquatic life but they also cause serious diseases in man. Nitrate coming from nitrogenous organic matter causes methaemoglobinemia in children in the range of 20 to 40 ppm.

e. WHO pointed out that shell fish can concentrate mercury to the level of 10 mg per kg. Mercury poisoning caused Minamata disease in Japan in 1953 and killed several people.

Adverse Effect of Water Pollutant # 2. Effects of Organic Water Pollutants:

a. Organic compounds in water undergo degradation and putrefaction by bacterial activity. They consume dissolved oxygen which is an essential requirement of aquatic biota.

b. Organic matter coming from domestic and agricultural land contains nutrients which nourish algal growth. There occurs a loss of all DO content resulting in dead pool of water.

Adverse Effect of Water Pollutant # 3. Effects of Sewage and Domestic Wastes:

a. Domestic sewage, which is primarily composed of spent water containing wine, faeces, soapy wastes, food materials and paper makes the water extremely anaesthetic.

b. Accumulation of sewage and domestic wastes in water bodies retards the self-regulatory capabilities of aquatic organisms. Self-purifying ability of water is lost and it becomes unfit for domestic purposes.

c. Sewage poses major threat to water courses. Today developed countries are fighting against thermal and chemical pollutants, while Indians have to combat with chemicals and pathogens with their limited resources.

Adverse Effect of Water Pollutant # 4. Effects of Sediments:

a. Sediments decrease fish population by blanketing fish nests, spawn and food supplies.

b. Suspension may cause thickening of fish gills which may lead to asphyxiation of the fish.

c. These result in less food availability and plant biomass.

d. Sediments make the water cloudy and increase the cost of water treatment used for culinary purposes. Due to turbid water, the hunting ability of fish gets curtailed.

Adverse Effect of Water Pollutant # 5. Effects of Synthetic Detergents:

a. Detergent enzymes are potential allergens and can cause serious complications if inhaled or when they penetrate the body through wounds or cuts.

b. Complex formation between NTA (nitrilotriacetate) and Hg or Cd increases the possibilities of transmission across the placental barrier into a foetus, thereby increasing the likelihood of birth defects.

c. NTA is degraded in waste treatment systems, but under anaerobic conditions it exists in some septic tanks. These NTA may persist and get back to a water-well system.

d. Phosphate, the major ingredient of most detergents, favours the luxuriant growth of algae which forms algal blooms. Such decomposing waters are known to produce toxins as strychnine which kill animals.

e. The surface active ingredients which are not easily degradable cause nuisance at sewage works by creating foam and froth. It has been reported that about 50% of these substances occur in the final effluents.

f. The increased use of syndets, which replace surface active agents like soap are able to produce foams even in very low concentrations, so aeration is not possible. As a result, the rate of re-aeration of river water as well as the efficiency of sewage purification is reduced.

g. Laboratory experiments have proved that water plants are adversely affected by syndets. They also produce foul tastes in water bodies.

Adverse Effect of Water Pollutant # 6. Effects of Pathogens:

a. Parasites are considerably harmful for man. Eggs of nematodes, hook worms and tape worms occur mostly in crude sewage. When such sewage is discharged into water bodies without treatment, contamination of water occurs resulting in danger to man and aquatic life.

b. The enteric diseases are transmitted mainly by drinking contaminated water or swallowing food. The pathogens most frequently transmitted through water cause infections of intestinal tract like typhoid, paratyphoid, amoebic dysentery, cholera, polio and infectious hepatitis.

c. Intestinal helminthes, i.e., Ascaris lumbricoides and Trichuristrichiura are also water borne. Entamoeba histolytica is the casual agent which causes internal amoebiasis and several extra-intestinal diseases.

Adverse Effect of Water Pollutant # 7. Effects of Radioactive Pollutants in Water:

Living organisms are considered as the prey for radioactive contaminants in water. As compared to organic poisons, injurious effects of radionuclides are exceedingly high.

a. Radioactive contaminants deposit on surface and ground water. This water consumed by plants during photosynthesis acts as a medium for radioactivity in them.

b. In living organisms, radiation produces a whole host of extremely hazardous species like H + , H2, H2O – , H2O + , e – , e + , HO2, H3O – and H2O2 etc., causing severe effects.

c. The radioactive materials in water react with proteins of aquatic invertebrates and appear to deactivate enzymes by breaking S—H—S hydrogen bonds. With enzyme inhibition, cell growth may continue, but cell division may be stopped.

d. Traces of radioactive materials present in water cause cancers, leukemia, eye cataract, DNA breakage and carcinoma in man.

e. Drinking water containing Rn-222, Ra-226 and Th-232 could accumulate dangerously in man causing somatic and genetic disorders.

Adverse Effect of Water Pollutant # 8. Effects of Eutrophication:

a. Eutrophication causes several physical, chemical and biological changes which considerably deteriorate the water quality.

b. During eutrophication, algal bloom releases toxic chemicals which kill fish, birds and other aquatic animals causing the water to sink.

c. Decomposition of algal bloom leads to oxygen depletion in water. Thus with a high CO2 level and poor oxygen supply, aquatic organisms begin to die and the clean water turns into a stinking drain.

d. Many pathogenic microbes, viruses, protozoa and bacteria etc. grow on sewage products under anaerobic conditions. It results into spread of fatal water-borne diseases such as polio, dysentery, diarrhoea, typhoid and viral hepatitis.

e. In India, Dal, Nagin, Loktak lake and Hussain sagar are seriously chocked by aquatic weeds affecting fisheries production, utility for aquatic flora and aesthetic value.

Adverse Effect of Water Pollutant # 9. Effects of Thermal Pollution on Aquatic Ecosystem:

a. Reduction in dissolved oxygen:

DO content is decreased in the warm water. Normal, biological reduction of DO level of the atmospherically unreplenished lower layer of water may give rise to anaerobic conditions leading to fish mortality.

b. Direct fish mortality:

There appear to be particular temperature ranges that are tolerated by fish and other related species. For example, lethal temperature for trout is 77°F, for yellow perch 88°F and for carp it is 85°F. Thus thermal death of fish may occur due to the action of heat on nervous system, inactivation of enzymes and coagulation of cell protoplasm.

c. Interference with reproduction:

The increased temperature triggers deposition of eggs by female. Other activities like nest building, spawning, hatching and migration etc. get disturbed by rising temperature.

High temperature increases activities in aquatic animals, which exhaust the organisms and shortens their life. Generally the speed of a chemical change is doubled for every 10°C rise in temperature. Daphie lives for 40 days at 8°C while 29 days at 21°C.

e. Increased vulnerability to disease:

Some bacteria such as, chondroccus grow rapidly with rising water temperatures. It is believed to be responsible for the massive kill of blue black salmon on the Columbia river.

f. Invading destructive organisms:

Sometimes hot water permits the invasion of highly destructive organisms. A best example is the invasion of Shipworms into New Gersey’s Oyster Creek.

g. Destruction of aquatic animals:

Power plants require enormous amount of stream water for cooling purposes, even 500 million gallons per day. So a large number of fish, plankton and insect larvae may be sucked into the condenser along with the cooling water and destroyed by thermal shock, water velocity and pressure.

h. Changes in algae population:

Blue green algae and diatoms have different tolerance ranges for water temperature. Enriched nutrients and increased water temperature promote blue-green algal blooms.

i. Disruption of food chain:

Heated water effluents disturb aquatic food chain.

Adverse Effect of Water Pollutant # 10. Harmful Effects of Industrial Pollutants:

a. Industrial effluents cause deleterious effects on living organisms and may bring about death or sublethal pathology of kidneys, liver, lungs, brain and reproductive system.

b. It has been reported that free chlorine discharged by factories near Mirzapur in UP had caused heavy fish mortality in river Sone near Dehrion-son in Bihar.

c. Mercury poisoning among aquatic organisms has resulted in crippling and often fatal diseases like Minamata in Japan (1953). Effluents sometimes contain upto 10 times the level of Hg in natural water.

d. Industrial effluents consisting of As, Pb and cyanide etc. cause cellular degeneration in brain which results in figidity, coma, stupor and numbness.

e. Some of the trade wastes contain pathogenic bacteria. For instance, the pathogen Anthrax bacilli is present in tannery wastes.

f. Industrial discharges impart colour, foul odour and turbidity to the receiving waters. They undergo putrefaction to form objectionable tastes.


10.1: Atmospheric Pollution - Biology

0.19.4 is Atmosphère's fiftieth official release.

fusee-primary was last updated in: 0.19.3.

With thanks to the @switchbrew team, Atmosphère 0.19.4 is bundled with hbl 2.4.1, and hbmenu 3.4.0.

The following was changed since the last release:

  • Support was added for 12.0.3.
  • A number of minor issues were fixed, including:
    • An issue was fixed that could cause heap memory corruption when allocation was highly contended.
    • An issue was fixed that could cause sleep to fail under certain conditions.
    • An issue was fixed that could cause a scheduler slow path to be taken more often than necessary.

    For information on the featureset supported by 0.19, please see the official release notes.

    SciresM released this May 12, 2021

    0.19.3 is Atmosphère's forty-ninth official release.

    fusee-primary was last updated in: 0.19.3.

    With thanks to the @switchbrew team, Atmosphère 0.19.3 is bundled with hbl 2.4.1, and hbmenu 3.4.0.

    The following was changed since the last release:

    • Support was added for 12.0.2.
    • A number of minor issues were fixed, including:
      • An issue was fixed in dns.mitm that caused a crash when games attempted to resolve the IP address of nullptr.
      • An issue was fixed in erpt that would cause an abort when booting without having ever booted stock previously.
      • An issue was fixed in (file-based) emummc that caused an error on system format/downloading certain games.

      For information on the featureset supported by 0.19, please see the official release notes.

      SciresM released this Apr 30, 2021

      0.19.2 is Atmosphère's forty-eighth official release.

      fusee-primary was last updated in: 0.19.2.

      With thanks to the @switchbrew team, Atmosphère 0.19.2 is bundled with hbl 2.4.1, and hbmenu 3.4.0.

      Note: The erpt build in the 0.19.0 zip was updated on 2021/04/30 at 2:50 PM PST to fix a crash when booting without a pre-existing erpt savefile. The updated zip has a build hash of "-14ed4e40".

      The following was changed since the last release:

      • Atmosphère's components were further updated to reflect latest official behaviors as of 12.0.0.
        • Notably, erpt was updated to implement the new forced shutdown detection feature.
          • When a forced-shutdown occurs, an erpt_report will be generated and saved to the SD card on the next boot.
          • Initial inspections show mild-to-moderate optimizer improvements in several important places (kernel is 0x3000 smaller).
          • General system stability improvements to enhance the user's experience.
          • A bug was fixed that caused a black screen when attempting to boot firmware versions 2.0.0-4.1.0.
          • A bug was fixed that caused sm to abort when at the session limit, rather than returning error codes.
          • A bug was fixed that allowed for resource exhaustion on 12.0.0, under certain circumstances.

          For information on the featureset supported by 0.19, please see the official release notes.

          SciresM released this Apr 13, 2021

          0.19.1 is Atmosphère's forty-seventh official release.

          fusee-primary was last updated in: 0.17.0.

          With thanks to the @switchbrew team, Atmosphère 0.19.1 is bundled with hbl 2.4.1, and hbmenu 3.4.0.

          The following was changed since the last release:

          • An issue was fixed that caused a fatal error when using official migration services to transfer data between consoles.
          • An issue was fixed in ncm that caused an error when the OS tried to enumerate installed SD card content.
          • Several issues were fixed, and usability and stability were improved.

          And the following was changed in 0.19.0:

          • Support was added for 12.0.0.
            • mesosphère was updated to reflect the latest official kernel behavior.
            • sm , boot2 , pgl were updated to reflect the latest official behaviors.
              • Please Note: 12.0.0 added a new protocol for IPC ("tipc"), which has been freshly reimplemented in its entirety.
                • It is possible there may be as of yet unfound issues if there are, please send the appropriate crash reports to SciresM ( SciresM#0524 on discord).
                • Homebrew which uses atmosphere extensions (including the mitm API) will need to be re-compiled in order to function on 0.19.0.
                  • I apologize for this, but it's unavoidable for technical reasons. If you're affected by this and mad about it, please contact SciresM to complain.
                  • New features were added to erpt to track the activity of running applets, and to detect when a forced shutdown occurs.
                  • These behaviors have been temporarily stubbed, as they are not necessary for 12.0.0 to run (and their outputs won't be saved anywhere).
                  • A future atmosphère update will implement these behaviors, in the interest of reflecting official logic as faithfully as we can.
                  • Atmosphère's system modules are now bundled together in the single file "stratosphere.romfs".
                    • For those working on developing for atmosphère, executables inside the /contents/ directory will be preferred to those in "stratosphere.romfs".
                    • This will have no impact on user programs (it only removes programs with specific program ids).
                    • An extension InfoType was added for getting the current process handle, without having to spawn a thread and do IPC with oneself.
                    • An issue was fixed in SvcSetDebugThreadContext.
                    • An issue was fixed when doing IPC with user buffers.
                    • This was broken by Nintendo's introducing a dependency that made USB a requirement to launch before custom settings are parsed.
                    • Since the fix, you can now toggle the setting (as you could prior to atmosphère 0.9.4), and it will work as expected.
                    • Please Note: Enabling USB 3.0 often severely impacts wireless communications.
                      • Because of this, the setting will default to off. If you experience issues with it enabled, consider disabling it.
                      • Once completed, users will be able to interact with a Switch running atmosphère via a PC application ("Starlink") currently under development.
                        • Planned eventual features for connected consoles include a gdbstub, interacting with memory (for cheat development), streaming gameplay audio and video, and accessing the Switch's SD card filesystem.
                        • Switch homebrew will also have access to a (configurable and sandboxed) filesystem on the host PC, while connected.
                        • The "htc" system module was reimplemented completely.
                        • The system module which provides remote access to the SD card was reimplemented completely.
                        • A bug was fixed in dmnt that could cause a fatal when launching certain games with cheats active.
                        • An issue was fixed that could cause an abort in sm when using a large number of custom system modules.
                        • An issue was fixed that prevented launching gamecards on 1.0.0.
                        • Minor issues were fixed in the cheat virtual machine's behavior.

                        For information on the featureset supported by 0.19, please see the official release notes.

                        SciresM released this Apr 11, 2021

                        0.19.0 is Atmosphère's forty-sixth official release.

                        fusee-primary was last updated in: 0.17.0.

                        With thanks to the @switchbrew team, Atmosphère 0.19.0 is bundled with hbl 2.4.1, and hbmenu 3.4.0.

                        Note: The NCM build in the 0.19.0 zip was updated on 2021/04/11 at 5:45 AM PST to fix a random crash when deleting games. The updated zip has a build hash of "-c67c29eb".

                        The following was changed since the last release:

                        • Support was added for 12.0.0.
                          • mesosphère was updated to reflect the latest official kernel behavior.
                          • sm , boot2 , pgl were updated to reflect the latest official behaviors.
                            • Please Note: 12.0.0 added a new protocol for IPC ("tipc"), which has been freshly reimplemented in its entirety.
                              • It is possible there may be as of yet unfound issues if there are, please send the appropriate crash reports to SciresM ( SciresM#0524 on discord).
                              • Homebrew which uses atmosphere extensions (including the mitm API) will need to be re-compiled in order to function on 0.19.0.
                                • I apologize for this, but it's unavoidable for technical reasons. If you're affected by this and mad about it, please contact SciresM to complain.
                                • New features were added to erpt to track the activity of running applets, and to detect when a forced shutdown occurs.
                                • These behaviors have been temporarily stubbed, as they are not necessary for 12.0.0 to run (and their outputs won't be saved anywhere).
                                • A future atmosphère update will implement these behaviors, in the interest of reflecting official logic as faithfully as we can.
                                • Atmosphère's system modules are now bundled together in the single file "stratosphere.romfs".
                                  • For those working on developing for atmosphère, executables inside the /contents/ directory will be preferred to those in "stratosphere.romfs".
                                  • This will have no impact on user programs (it only removes programs with specific program ids).
                                  • An extension InfoType was added for getting the current process handle, without having to spawn a thread and do IPC with oneself.
                                  • An issue was fixed in SvcSetDebugThreadContext.
                                  • An issue was fixed when doing IPC with user buffers.
                                  • This was broken by Nintendo's introducing a dependency that made USB a requirement to launch before custom settings are parsed.
                                  • Since the fix, you can now toggle the setting (as you could prior to atmosphère 0.9.4), and it will work as expected.
                                  • Please Note: Enabling USB 3.0 often severely impacts wireless communications.
                                    • Because of this, the setting will default to off. If you experience issues with it enabled, consider disabling it.
                                    • Once completed, users will be able to interact with a Switch running atmosphère via a PC application ("Starlink") currently under development.
                                      • Planned eventual features for connected consoles include a gdbstub, interacting with memory (for cheat development), streaming gameplay audio and video, and accessing the Switch's SD card filesystem.
                                      • Switch homebrew will also have access to a (configurable and sandboxed) filesystem on the host PC, while connected.
                                      • The "htc" system module was reimplemented completely.
                                      • The system module which provides remote access to the SD card was reimplemented completely.
                                      • A bug was fixed in dmnt that could cause a fatal when launching certain games with cheats active.
                                      • An issue was fixed that could cause an abort in sm when using a large number of custom system modules.
                                      • An issue was fixed that prevented launching gamecards on 1.0.0.
                                      • Minor issues were fixed in the cheat virtual machine's behavior.

                                      For information on the featureset supported by 0.19, please see the official release notes.


                                      Air Pollution: Sources and Control (with diagram)

                                      We depend on air for our respiratory needs. So, air pollution causes injury to all living organisms.

                                      In case of plants, the growth and yield of crops are reduced and cause premature death. In animals including man, serious metabolic and respiratory diseases are manifested due to air pollution.

                                      Air pollution is also called as atmospheric pollution. The atmosphere is an invisible layer of gases that surround the earth.

                                      The atmosphere extends from the surface of earth upto 650 killometers. The lower most layer of atmosphere is known as troposphere which extends upto 8-10 km near the poles and 18-20 km near equator. Air pollution is largely confined to the lower atmosphere i.e. troposphere.

                                      The air comprises of four gases (99.99%) and a small amount of water vapour. These four gases are: Nitrogen (78.08%), Oxygen (20.95%), Argon (0.93%) and Carbon dioxide (0.03%). The oxygen and carbon dioxide are the two gases of air which directly interact with various biotic components through respiration and photosynthesis.

                                      Sources of Air Pollution:

                                      Air pollutants are gases, liquids and solids.

                                      The major sources of air pollutants are:

                                      (ii) Fuel combustion in stationary sources (21%)

                                      (iii) Industrial processes (14%),

                                      (iv) Solid waste disposal (5%),

                                      (vi) Miscellaneous sources including radioactive fallout (10%).

                                      So far, six pollutants, that account for most of the air pollution worldwide are carbon monoxide (CO), sulphur dioxide (SO2), nitrogen oxides (NOx), Ozone (O3), particulate matters (PM10) and lead. They may come from natural sources or from human activities. Natural sources of air pollution are volcanic eruption, discharge of spores, conidia, endospores etc. of airborne micro-organisms, pollens of certain flowers, dust particles suspended in air.

                                      Man Made Sources are, burning of fossil fuels (coal, natural gases, kerocine, petroleum products, etc.), burning of firewood for domestic purpose, automobile exhausts, smokes of domestic and industrial sources, particulate matters and aerosol etc.

                                      A brief description of atmospheric pollutants released through manmade sources is given below:

                                      1. Gases:

                                      A large amount of air pollution results from burning of coal and oils in furnaces and steel plants. They are burnt to produce heat energy along with gaseous and solid waste products. Gases produced during fuel combustion are CO, CO2, SO2, various oxides of nitrogen (NO, NO2, N2O4) and assorted hydrocarbons. Carbon monoxide (CO) is produced due to incomplete combustion of the carbon content of fossil fuels. Carbon dioxide (CO2) is produced due to complete combustion of carbon content.

                                      Hydrogen sulphide (H2S) is produced from refineries, sewage treatment and pulp mills. CO alone contributes to 47% air pollution. S02 is produced due to burning of coal and oil and from industrial processes. Nitrogen oxides are formed when fuel is burnt at very high temperature such as in industrial plants and transportation vehicles. Nitrogen monoxide (NO) is produced during combustion in the engine cylinder.

                                      When this gas passes out of the engine, it cools down and combines with more oxygen to form NO2 and N2O4. This mixture of gases is generally called as oxides of nitrogen (NOx). Ozone (O3) is another air pollutant which is a major component of photochemical smog which is formed from NOx, VOCs and oxygen in the presence of sunlight and heat.

                                      2. Particulate Matters:

                                      These are solid particles and liquid droplets suspended in air. They may be settled down where particle size is more than 10 μm or remain suspended in air when particle size is below 10 μm. Particulate matter in the size range of 0.01 μm to 50 μm or less in size), aerosols (less than 1 μm) flash and dust 0.25 to 500 μm), grit (more than 500 μm).

                                      Dust and flash cover the leaf surface reducing photosynthetic ability of leaves. Particulate matter below 5 μm size is usually deposited in respiratory tract. Smoke and fog reduce air visibility, photosynthetic efficiency of plants and cause respiratory distress and allergy in human beings.

                                      Fine dust particles released from cotton mills, floor mill or asbestos factory can cause serious respiratory problems and even may lead to cancer. Air borne microorganisms released during sneezing of diseased persons can spread air borne diseases. Jet aeroplanes release aerosol which contain CFC and can cause ozone layer depletion in stratosphere.

                                      3. Toxic Chemicals:

                                      Some highly toxic chemicals are emitted directly from different source^. For example, Arsenic emitted from coal and oil furnace and also from glass manufacturing units are directly delivered to air which is highly toxic. Similarly, C6H6 from refineries and motor vehicles, cadmium from smelters, burning waste, and coal and oil furnaces are some of the highly toxic chemicals acting as air pollutants.

                                      4. Secondary Pollutants:

                                      As stated earlier, these are formed from primary pollutants through wide range of photochemical reactions and cause greater damage than primary pollutants.

                                      When hydrocarbons from exhaust are exposed to light, alkanes, ethylenes, unsaturated hydrocarbons, aldehydes and aromatics are formed. One of these compounds is benzopyrene which induces cancer in man. Two other photochemically originated pollutants are peroxybenzoil nitrate and peroxyacetyl nitrate (PAN).

                                      Some other secondary pollutants for air pollution are sulphur dioxide (2H2S + 3O2 →2SO2 + 2H2O), Sulphuric acid mist (2SO2 + O2→ 2SO3, SO3 + H2O→ H2SO4) and smog (Hydrocarbons + NO2 + sunlight→ Peroxyocetyl nitrate + HCHO + OH).

                                      The word ‘smug’ was first used in 1905 to describe the combination of smoke and fog in London which totally obscured visibility for few hours. This smog resulted from S02, soot and tarry materials released into the atmosphere by burning of high-sulphur coal.

                                      Some other secondary air pollutants are:

                                      (a) NO: Formed by dissociation of N02 to atomic oxygen and NO.

                                      (b) NO2: formed in sunlight from NO (NO + O → NO2)

                                      (c) OH (Hydroxy radical): Formed in sunlight from hydrocabons and nitrogen oxides. It reacts with other gases to form acid droplets.

                                      (d) HONO (Nitrous acid): Formed from NO2 and water vapours.

                                      (e) HN03 (Nitric acid): Formed from NO2 and is a major component of acid rain.

                                      Effects of Air Pollution:

                                      The effect of air pollution has been extensively studied in man and animals, in plants and in climatic changes.

                                      A few of them are described below:

                                      1. Acute health hazard:

                                      Smog in Donora, Pennsylvania along Monogahila River in 1948 resulted 6,000 illness and 20 deaths in a population of 14,000. Photochemical smog in London in 1952 and 1956 has caused eye and throat irritation. In India, a most terrible effect of air pollution has been witnessed in Bhopal on December 3, 1984. Leakage of Methyl Isocyanate from Union Carbide factory caused number of deaths in a few minutes.

                                      2. Chronic diseases:

                                      Incidence of respiratory diseases in Delhi is about 12 times higher than the national average. Carbon monoxide if present in air can combine with blood haemoglobin 7 to 10 times faster than O2. CO concentration 30 ppm for 4 hours can convert 5% of body haemoglobin into carboxy haemoglobin. Prolonged exposure to CO could cause death due to lack of O2 supply to living cells of the body.

                                      Diseases like bronchitis, lungs cancer and emphysema are caused by air pollution. N02 in air causes bronchitis and lowers resistance to influenza. SO2 obstructs breathing and irritates eyes. Silicon tetrafloride irritates lungs. Nitric acid, nitrous acid and sulphuric acid initiate respiratory disease. Photochemical smog causes eye irritation and headache. Constant exposure to peroxyacetyl nitrate (PAN) aggravates asthma and can damage lungs.

                                      Air pollution produces offensive odours and gives general discomfort, anxiety or suffering to people. Long term exposure to benzene causes low WBC count and leukaemia. Similarly, long term exposure to arsenic may cause lung and skin cancer. Exposure to cadmium damages kidney and lungs and weakens bones. Prolonged exposure to nickel may cause lung cancer. Exposure to lead causes highpertension and impair growth. Long term exposure to manganese may contribute to Purkinson’s disease.

                                      3. Reduction in Visibility:

                                      Smokes, fumes, fog and particulates in air absorb solar radiation and reduce the quantity of solar radiation reaching the earth surface. Smokes and fumes increase atmospheric turbidity. Particulates absorb and reflect incoming solar radiation, thus reducing 15 to 20% of total radiation reaching the earth surface. Cause of many accidents is reduction of visibility due to smoke and fog in the atmosphere.

                                      4. Effects on plants:

                                      Air pollution has devastating effect on plants, ultimately resulting in lower yield. It damages the crops and trees. According to an estimate there has been 5 to 10% crop loss due to ozone pollution. SO2 causes bleaching of leaves, chlorosis, growth suppression and yield reduction. PAN produces glazing, silvering or bronzing on the lower surface of leaves. Hydrogen fluoride (HF) could also cause chlorosis, dwarfing, leaf abscission and lower yield. Chloride (Cl2) develops bleaching spots and leaf abscission. Ethylene (C2H4) causes leaf abnormalities and withering, flower dropping and failure of the flower to open.

                                      5. Effect on Climate:

                                      Particulates of air play a vital role in producing temperature changes and air movements. Solid particulates take part in cloud formation. Since urban air pollution is more, there is increased particulate matter in air, increased cloud formation (upto 10% in comparison to rural areas) and 10% more wet days. There is increased amount of mist, fog and smog in industrial areas.

                                      Control of Air Pollution:

                                      Atmospheric pollution can be controlled effectively by using some of the following techniques.

                                      1. Use of tall chimneys:

                                      Industries should be asked to build up high chimneys for escape of smoke, fumes so that harmful gases may not spread in the lower layer of atmosphere.

                                      2. Use of CNG:

                                      Automobiles in Delhi account for 50% of air pollution and 90% of CO are released to air from automobiles. Recently Delhi Administration has emphasized use of Compressed Natural Gas’ (CNG) in place of petrol and diesel to reduce air pollution.

                                      3. Removal of pollutant from fuel:

                                      A lead compound, tetraethyl lead (TEL) is mixed in petrol for smooth and easy running of the vehicles. But the exhaust is leaded gas and particulate lead. Lead mixed air when inhaled, is injurious for kidney, liver and blood. When mixed with food and water, it may lead to poisoning. Therefore unleaded petrol must be available in the petrol pumps.

                                      4. Use of catalytic converters:

                                      Removal of pollutants from fossil fuel with be possible by use of catalytic converters in two, three and four wheelers. The catalytic converter has expensive metals like platinum, paladium and rhodium as catalysts. When the poisonous exhaust gases pass through catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water. Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas respectively.

                                      Smoking tobaco is injurious to health because its smoke contains nearly seven polycyclic hydrocarbons and radioactive polonium-210 which are said to be carcinogenic. An average smoker has the risk of developing and dying from lung cancer ten times more than a nonsmoker.

                                      5. Use of scrubber: (Fig. 9.1) A scrubber can remove gases like sulphur dioxide and ammonia. In a scrubber, the exhaust is passed through a spray of water or lime.

                                      6. Use of electrostatic precipitator (Fig. 9.1):

                                      For removing particulate matter from air, electrostatic precipitator is used, which can remove 99% particulate matter present in the exhaust of thermal power plants. It has electrodes with supply of several thousand volts of electric current, which produce a corona that releases electrons. These electrons attach to particles giving them net negative charge. The collecting plates are positively charged and attract the negatively charged particles.

                                      7. Proper treatment of Organic Wastes:

                                      Public awareness regarding air pollution potential of sewage and many other solid wastes will help in reducing air pollution. It should be mandatory for municipalties to carry-out proper treatment of sewage and other wastes before disposal.

                                      8. Development of green covers:

                                      More effort should be made for extensive green coverage development because the green plants serve as sinks for air pollutants. Many plant species have been evaluated for their scavenging potential against air pollutants.

                                      9. Bioremediatieon:

                                      Many countries have started the use of microorganisms to treat air, water and instrial wastes. Japan is exploring various uses of biovemediation. For example, use of microorgnisms to manufacture advanced biodegradable polymers or to produce clean burning fuel like hydrogen.

                                      10. Pollution Control at source is a better preventive measure. This would facilitate not releasing pollutant into air.

                                      In India, the Air (Prevention and control of Pollution) Act came into force in 1981 but was amended in 1987 to include noise as an air pollutant. Government has established pollution Control Boards in State Headquarters. In spite of all reactions, public awareness is the basic need to fight against pollution.


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                                      Air pollution

                                      Air pollution consists of chemicals or particles in the air that can harm the health of humans, animals, and plants. It also damages buildings.

                                      Biology, Ecology, Earth Science, Geography

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                                      Air pollution consists of chemicals or particles in the air that can harm the health of humans, animals, and plants. It also damages buildings. Pollutants in the air take many forms. They can be gases, solid particles, or liquid droplets.

                                      Sources of Air Pollution

                                      Pollution enters the Earth's atmosphere in many different ways. Most air pollution is created by people, taking the form of emissions from factories, cars, planes, or aerosol cans. Second-hand cigarette smoke is also considered air pollution. These man-made sources of pollution are called anthropogenic sources.

                                      Some types of air pollution, such as smoke from wildfires or ash from volcanoes, occur naturally. These are called natural sources.

                                      Air pollution is most common in large cities where emissions from many different sources are concentrated. Sometimes, mountains or tall buildings prevent air pollution from spreading out. This air pollution often appears as a cloud making the air murky. It is called smog. The word "smog" comes from combining the words "smoke" and "fog."

                                      Large cities in poor and developing nations tend to have more air pollution than cities in developed nations. According to the World Health Organization (WHO), some of the worlds most polluted cities are Karachi, Pakistan New Delhi, India Beijing, China Lima, Peru and Cairo, Egypt. However, many developed nations also have air pollution problems. Los Angeles, California, is nicknamed Smog City.

                                      Indoor Air Pollution

                                      Air pollution is usually thought of as smoke from large factories or exhaust from vehicles. But there are many types of indoor air pollution as well.

                                      Heating a house by burning substances such as kerosene, wood, and coal can contaminate the air inside the house. Ash and smoke make breathing difficult, and they can stick to walls, food, and clothing.

                                      Naturally-occurring radon gas, a cancer-causing material, can also build up in homes. Radon is released through the surface of the Earth. Inexpensive systems installed by professionals can reduce radon levels.

                                      Some construction materials, including insulation, are also dangerous to people's health. In addition, ventilation, or air movement, in homes and rooms can lead to the spread of toxic mold. A single colony of mold may exist in a damp, cool place in a house, such as between walls. The mold's spores enter the air and spread throughout the house. People can become sick from breathing in the spores.

                                      Effects On Humans

                                      People experience a wide range of health effects from being exposed to air pollution. Effects can be broken down into short-term effects and long-term effects.

                                      Short-term effects, which are temporary, include illnesses such as pneumonia or bronchitis. They also include discomfort such as irritation to the nose, throat, eyes, or skin. Air pollution can also cause headaches, dizziness, and nausea. Bad smells made by factories, garbage, or sewer systems are considered air pollution, too. These odors are less serious but still unpleasant.

                                      Long-term effects of air pollution can last for years or for an entire lifetime. They can even lead to a person's death. Long-term health effects from air pollution include heart disease, lung cancer, and respiratory diseases such as emphysema. Air pollution can also cause long-term damage to people's nerves, brain, kidneys, liver, and other organs. Some scientists suspect air pollutants cause birth defects. Nearly 2.5 million people die worldwide each year from the effects of outdoor or indoor air pollution.

                                      People react differently to different types of air pollution. Young children and older adults, whose immune systems tend to be weaker, are often more sensitive to pollution. Conditions such as asthma, heart disease, and lung disease can be made worse by exposure to air pollution. The length of exposure and amount and type of pollutants are also factors.

                                      Effects On The Environment

                                      Like people, animals, and plants, entire ecosystems can suffer effects from air pollution. Haze, like smog, is a visible type of air pollution that obscures shapes and colors. Hazy air pollution can even muffle sounds.

                                      Air pollution particles eventually fall back to Earth. Air pollution can directly contaminate the surface of bodies of water and soil. This can kill crops or reduce their yield. It can kill young trees and other plants.

                                      Sulfur dioxide and nitrogen oxide particles in the air, can create acid rain when they mix with water and oxygen in the atmosphere. These air pollutants come mostly from coal-fired power plants and motor vehicles. When acid rain falls to Earth, it damages plants by changing soil composition degrades water quality in rivers, lakes and streams damages crops and can cause buildings and monuments to decay.

                                      Like humans, animals can suffer health effects from exposure to air pollution. Birth defects, diseases, and lower reproductive rates have all been attributed to air pollution.

                                      Global Warming

                                      Global warming is an environmental phenomenon caused by natural and anthropogenic air pollution. It refers to rising air and ocean temperatures around the world. This temperature rise is at least partially caused by an increase in the amount of greenhouse gases in the atmosphere. Greenhouse gases trap heat energy in the Earths atmosphere. (Usually, more of Earths heat escapes into space.)

                                      Carbon dioxide is a greenhouse gas that has had the biggest effect on global warming. Carbon dioxide is emitted into the atmosphere by burning fossil fuels (coal, gasoline, and natural gas). Humans have come to rely on fossil fuels to power cars and planes, heat homes, and run factories. Doing these things pollutes the air with carbon dioxide.

                                      Other greenhouse gases emitted by natural and artificial sources also include methane, nitrous oxide, and fluorinated gases. Methane is a major emission from coal plants and agricultural processes. Nitrous oxide is a common emission from industrial factories, agriculture, and the burning of fossil fuels in cars. Fluorinated gases, such as hydrofluorocarbons, are emitted by industry. Fluorinated gases are often used instead of gases such as chlorofluorocarbons (CFCs). CFCs have been outlawed in many places because they deplete the ozone layer.

                                      Worldwide, many countries have taken steps to reduce or limit greenhouse gas emissions to combat global warming. The Kyoto Protocol, first adopted in Kyoto, Japan, in 1997, is an agreement between 183 countries that they will work to reduce their carbon dioxide emissions. The United States has not signed that treaty.

                                      In addition to the international Kyoto Protocol, most developed nations have adopted laws to regulate emissions and reduce air pollution. In the United States, debate is under way about a system called cap and trade to limit emissions. This system would cap, or place a limit, on the amount of pollution a company is allowed. Companies that exceeded their cap would have to pay. Companies that polluted less than their cap could trade or sell their remaining pollution allowance to other companies. Cap and trade would essentially pay companies to limit pollution.

                                      In 2006 the World Health Organization issued new Air Quality Guidelines. The WHOs guidelines are tougher than most individual countries existing guidelines. The WHO guidelines aim to reduce air pollution-related deaths by 15 percent a year.

                                      Anybody can take steps to reduce air pollution. Millions of people every day make simple changes in their lives to do this. Taking public transportation instead of driving a car, or riding a bike instead of traveling in carbon dioxide-emitting vehicles are a couple of ways to reduce air pollution. Avoiding aerosol cans, recycling yard trimmings instead of burning them, and not smoking cigarettes are others.

                                      Photograph by Trudy Muegel, MyShot

                                      Downwinders
                                      The United States conducted tests of nuclear weapons at the Nevada Test Site in southern Nevada in the 1950s. These tests sent invisible radioactive particles into the atmosphere. These air pollution particles traveled with wind currents, eventually falling to Earth, sometimes hundreds of miles away in states including Idaho, Utah, Arizona, and Washington. These areas were considered to be "downwind" from the Nevada Test Site.

                                      Decades later, people living in those downwind areascalled "downwinders"began developing cancer at above-normal rates. In 1990, the U.S. government passed the Radiation Exposure Compensation Act. This law entitles some downwinders to payments of $50,000.

                                      London Smog
                                      What has come to be known as the London Smog of 1952, or the Great Smog of 1952, was a four-day incident that sickened 100,000 people and caused as many as 12,000 deaths. Very cold weather in December 1952 led residents of London, England, to burn more coal to keep warm. Smoke and other pollutants became trapped by a thick fog that settled over the city. The polluted fog became so thick that people could only see a few meters in front of them.

                                      Greenhouse Gases
                                      There are five major greenhouse gases in Earth's atmosphere.


                                      Scientists Map Rivers of Pollution in the Sky

                                      An atmospheric river carrying dust particles blows across the North Atlantic Ocean from Africa to the Caribbean in July 2018. Credit: Suomi/NPP satellite images from NASA Worldview website. Animation by climate.gov

                                      Windy regions high in the atmosphere can transport pollutants like dust or soot thousands of miles around the world and disrupt everyday life for thousands of people.

                                      Last summer, “Godzilla” came for the Caribbean and the U.S. Gulf Coast. This particular monster wasn’t of the sci-fi variety, but, rather, a massive dust storm kicked up by winds from the Sahara Desert and carried an ocean away. The dust storm was an extreme example of a phenomenon that happens regularly: the global transport of dust, soot, and other airborne particles, collectively known as aerosols, by jets of winds in the atmosphere. The result is the formation of what are called aerosol atmospheric rivers.

                                      Gaining a better understanding of how these particles are transported around the globe is important because certain aerosols can nourish rainforest soil, help or hinder cloud formation, reduce visibility, or affect air quality – which can impact human health. But studies of aerosol transport have tended to focus on single events in a particular part of the world. There wasn’t really a way of looking at them in a holistic, global way.

                                      In a first, a recent study published in the journal Geophysical Research Letters does just that. Five types of aerosols are of particular interest to researchers: dust, two kinds of carbon particles (soot and organic carbon), sulfate (emitted during events like volcanic eruptions or the burning of fossil fuels), and sea salt. The authors identified where aerosol atmospheric rivers tend to occur and how often extreme events, similar to the Godzilla dust storm, happen each year. To do this, they took a computer program they previously developed to detect atmospheric rivers around the world that move water vapor and produce precipitation, and they modified it to detect aerosol atmospheric rivers instead.

                                      The shift from using atmospheric rivers to study the movement of water vapor to using them to study aerosol transport was something of a revelation, because researchers only started to use the global detection framework of atmospheric rivers to look at the movement of extreme amounts of water vapor about six years ago. The concept of atmospheric rivers is only about 20 years old.

                                      “It took scientists time to recognize and leverage atmospheric rivers as a concept,” said Duane Waliser, one of the study’s co-authors and an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Southern California. And it wasn’t until Waliser was speaking to his colleague, Arlindo da Silva, an aerosol researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, about the atmospheric river concept that a light went on for both of the researchers. “‘We should take our algorithm and apply it to your aerosol dataset,’” Waliser said.

                                      Location, Location, Location

                                      After modifying the atmospheric river algorithm for aerosol atmospheric rivers, the study’s authors applied it to a state-of-the-art reconstruction of Earth’s atmosphere called the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) from NASA’s Global Modeling and Assimilation Office. It incorporates datasets from satellites, airborne instruments, and sensors on the ground from 1980 to the present to produce a representation of the structure of Earth’s atmosphere every six hours.

                                      MERRA-2 enabled the researchers to look back in time to analyze the location and frequency of aerosol atmospheric rivers around the world from 1997 to 2014. The study authors found that regions including the Sahara, Patagonia, Asian deserts, and Namibia are big sources of dust aerosol atmospheric rivers, while areas like the eastern U.S., the southern Amazon and Africa, and northern India tend to produce ones dominated by soot resulting from wildfires and the burning of fossil fuels.

                                      The analysis also showed these atmospheric rivers tend to move large amounts of aerosols in a limited number of extreme events instead of in a steady stream throughout the year.

                                      “We were astonished to find that a few major events a year can transport between 40% to 100% of the aerosols moved by the atmosphere,” said Sudip Chakraborty, an atmospheric scientist at JPL and a study co-author.

                                      Now that scientists have a way of looking at aerosol atmospheric rivers globally, the framework gives them a way to study how these particle-laden rivers in the sky affect Earth’s climate. This includes how aerosols interact with clouds to potentially supercharge storms, how they trap or reflect heat in the atmosphere, and whether phenomena like El Niño and La Niña affect atmospheric aerosol river pathways and frequency.

                                      The new approach also gives researchers insight into how aerosol atmospheric rivers could affect communities around the world, through their impacts on air quality and visibility and their ability to move plant pathogens that can affect crops. “When you realize a lot of the transport is happening in just a few big events, then you know to focus on those big events,” said da Silva.

                                      Reference: “Extending the Atmospheric River Concept to Aerosols: Climate and Air Quality Impacts” by Sudip Chakraborty, Bin Guan, Duane E. Waliser, Arlindo Da Silva, Sophie Uluatam and Peter Hess, 2 March 2021, Geophysical Research Letters.
                                      DOI: 10.1029/2020GL091827


                                      Watch the video: Air Pollution (January 2022).