Atmospheric Pollution Dr. Manish Semwal GMIS

Concept of Atmospheric Pollution

Atmospheric Pollution The quality of the air we breathe is both a personal health and a major economic issue Every industrialized country has to grapple with this issue and it appears that some countries with rapidly expanding economies (e.g., China) are making the same pollution mistakes as the United States did earlier As youll see, air pollution is often an international issue since the air pollution generated in one country can be transported to another by the prevailing winds

Rain and acidity Rain, in its theoretically normal, unpolluted state, is slightly acid, with pH 5.6, due to carbonic acid (H 2 CO 3 ) which is a product of the dissolution of atmospheric carbon dioxide (CO 2 ) Rain, in its theoretically normal, unpolluted state, is slightly acid, with pH 5.6, due to carbonic acid (H 2 CO 3 ) which is a product of the dissolution of atmospheric carbon dioxide (CO 2 ) Acid rain is defined as rain with a pH<5.6 Acid rain is defined as rain with a pH<5.6

Rain and acidity The oxides of sulfur and nitrogen (SO x and NO x ) are oxidized in the atmosphere and form sulfuric and nitric acids (H 2 SO 4 and HNO 3 ) The oxides of sulfur and nitrogen (SO x and NO x ) are oxidized in the atmosphere and form sulfuric and nitric acids (H 2 SO 4 and HNO 3 ) These acids contribute to rain acidity These acids contribute to rain acidity Sulfur compounds (and maybe also nitrogen compounds) can be transported several hundred kilometers per day in the atmosphere Sulfur compounds (and maybe also nitrogen compounds) can be transported several hundred kilometers per day in the atmosphere Chlorine emission may also result in acidity (hydrochloric acid HCl), but usually only close to emission sources Chlorine emission may also result in acidity (hydrochloric acid HCl), but usually only close to emission sources

Sources of S and N in atmosphere Sulfur oxides are primarily emitted from stationary sources, such as utility and industrial coal-burning boilers Sulfur oxides are primarily emitted from stationary sources, such as utility and industrial coal-burning boilers Nitrogen oxides are emitted from both stationary and mobile sources, especially automobiles Nitrogen oxides are emitted from both stationary and mobile sources, especially automobiles

Data from US EPA (1977): ~56% of NO x was caused from the burning of fossil fuels by stationary sources ~56% of NO x was caused from the burning of fossil fuels by stationary sources 40% came from transportation-related sources 40% came from transportation-related sources Sources of S and N in atmosphere The combustion of fossil fuel in the US results in ~50 million metric tons of SO x and NO x being emitted to the atmosphere per year

Ecological effects of acid rain Degradation of water quality Degradation of water quality Decrease in fish productivity Decrease in fish productivity Decrease in forest productivity Decrease in forest productivity Accelerated soil leaching Accelerated soil leaching

Less concern about effect of acid rain is usually caused by: data unavailability or only few data are available data unavailability or only few data are available – about chemical characteristic of precipitation – environmental degradation caused by changes of precipitation chemistry emission of SO x and NO x are thought as only causing less environmental effects emission of SO x and NO x are thought as only causing less environmental effects Why Ecological effects of acid rain are recognized

Research Initiative for IA ( If Required) Sites to be analyzed? Sites to be analyzed? Sampling methods? Time? Sampling methods? Time? Chemical analysis? Methods and pollutants/compounds to be analyzed? Chemical analysis? Methods and pollutants/compounds to be analyzed? Ecological analysis? Type of indicators and organism to be investigated? Ecological analysis? Type of indicators and organism to be investigated? Statistical methods? Statistical methods? Possible interpretation? Possible interpretation?

Acid Rain and Trees

Dissolution of Limestone and Marble

Dissolution of Marble

Stratospheric Ozone Stratosphere – volume of Earths atmosphere that extends from ~ 10 – 15 km altitude to an altitude of ~ 50 km; it contains about 90% of the atmospheres naturally occurring ozone How does stratospheric ozone benefit life on Earth?

Where is ozone the good guy ? trophosphere stratosphere

Ground-level Ozone Ozone (O 3 ) – a pale blue gas that near the Earths surface is a component of photochemical (light induced) smog E.G., NO x (nitrogen oxides) gases are released from vehicle exhaust; sunlight energy breaks the bond between the N and O atoms in the NO x compound Then O + O 2 O 3 Why should we care? LA smog

Ozone Depletion Over Northern Hemisphere Source: Data from NASA, Goddard Space Flight Center.

Stratospheric Ozone Ramifications of stratospheric ozone reduction? 1) Increase in skin cancers 2) Increase in eye disorders 3) Decrease in immune response 4) Decrease in plant productivity 5) Possible enhancement of Greenhouse Effect due to less plant productivity 6) Increase in ground-level ozone concentrations

The Montreal Protocol has reduced use of CFC s, but… Their long life span means that they will be in the stratosphere for a long time, still destroying ozone. However, the rate of increase of ozone depletion has slow, showing we are on the right track By the way, ozone holes are opening up in places other than Antarctica

Bibliography e.asp?a=73 /page.cfm?pageID=551

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