which pollution holds the highest priority among all the manmade problems?
Answers
Answer:
Environmental issues change from place to place and time to time. The issues include local as well as global issues. The understanding of issues is necessary to find solution. Air pollution issues have changed over a period of time. Issues like atmospheric brown cloud, climate change, hazardous air pollutants, black/muddy snow which are hardly discussed few decades back have now gaining importance. This chapter elaborates major issues due to air pollution.
Pollution’ is originated from Latin word ‘Pollutus’ which means ‘foul or unclear’. Air pollution can be defined as ‘Atmospheric condition in which substances is present at concentrations higher than their normal ambient levels to produce significant effects on humans, animals, vegetation or materials’ (Seinfeld 1986).
Air composition
The air we breathe is most important natural resource which allows us to survive. The composition of air around us keeps changing continuously due to both natural as well as man made emissions into the atmosphere. Earth’s atmosphere is a layer of gases retained by the gravity. On an average, as shown in Fig. 1.1 dry air consists of 78.09 % of nitrogen, 20.95 % of oxygen, 0.93 % of argon and 0.039 % of carbon dioxide by volume. Minor constituents such as methane (CH4), Ozone (O3), Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Nitrous Oxide (N2O), Carbon Monoxide (CO), Ammonia (NH3) etc. are also present having very low mixing ratios. These constituents do vary place to place due to change in atmospheric conditions. The air constituents over the sea will not be same as at the shore; sea shore air may not have same concentrations of the constituents as desert air. Sea shore air will be dominated by water vapour where as desert air will have more suspended dust. Similarly, the thick Amazon forest will have more water vapour and volatile organic compounds whereas he air above solid waste dumping site is likely to have more methane and ammonia.
Explanation:
Air Pollution :-
Air pollution can be defined as 'Atmospheric condition in which substances is present at concentrations higher than their normal ambient levels to produce significant effects on humans, animals, vegetation or materials' (Seinfeld 1986).