The public is generally aware of air pollution because of media coverage of acid-rain, damaged lakes and mercury-contaminated fish, but is less aware of its effects on terrestrial ecosystems. In some ways the terrestrial effects are more subtle because many soils are well buffered against acid inputs and the long life span of many terrestrial plants,means that biological community changes play out in slow motion. Terrestrial researchers have tended to focus on microbial and geochemical effects in the soil as indicators of ecosystem sensitivity; with a few exceptions, effects on the plant and animal communities have received less research attention.

Some sources of air pollution are: burning of fossil fuels like wood which releases CO2, emissions from automobiles like CO and hydrocarbon, agricultural activities which involves spraying of pesticides, explosives used in wars like bombs, emissions from industries and emissions of gas from active volcanoes.

Some effects of air pollution on plants are chlorosis and even death of cells and tissue caused by SO2, damage of leafy vegetables such as lettuce and spinach by fluorides and peroxyacetyle nitrates, reduction in crop yield by oxides of nitrogen, smog bleaches and blaze foliage of important leafy plants, hydrocarbons cause premature yellowing and fall of leaves and discoloration of sepals and petals, smoke and dust cover the leaf and reduce photosynthetic capacity of plants.

On the other hand, the effect of air pollutants on animals and man are as follows; Ozone has been reported to produce chromosomal aberrations.SO3, CO and NO2 diffuse into blood stream and reduce oxygen transport. CO damages cardiovascular system.Ozone causes pulmonary congestion. Smoking of tobacco causes cancerous growth in lungs etc. As a result, while much is known about deposition, accumulation and mechanisms of damage of air pollutants in terrestrial systems, less is known about thresholds of impact on biota, in particular the ultimate threshold of death for an organism. Regardless of this, evidence from many terrestrial ecosystems indicates that the significance, severity and scope of this threat is worthy of conservation.

In general, the biogeochemical impacts of Sulphur and Nitrogen on ecosystems depend upon their mobility in the canopy and soils to which they are deposited. If the anions (negatively charged ions) they form (sulfate and nitrate) are leached through the canopy, rather than being retained, they can strip the foliage and soils of valuable nutrient cations (positively charged ions) such as calcium and magnesium. Accumulation of Nitrogen in terrestrial ecosystems can cause shifts in species composition as Nitrogen-loving species outcompete those species better adapted to less fertile soils. Nitrogen accumulation may also lead to a condition known as Nitrogen saturation, in which overabundance of these key nutrient results in a cascade of impacts on microbial and plant production and Nitrogen cycling. Ozone is a well-studied pollutant known to be toxic to plants and animals. In plants, Ozone appears to affect membrane function, leading to reduction in photosynthesis, slower growth and in severe cases, death. In animals, Ozone effects have mainly been studied in humans, where it damages lung tissue and exacerbates respiratory problems such as asthma. Mercury is known to accumulate in soils, but effects research has primarily focused on aquatic ecosystems where anaerobic conditions facilitate the production of the highly toxic form called methyl-mercury.




CONTROL OF AIR POLLUTION

The height of chimneys should be increased to the highest possible level to reduce pollution at ground level. Nuclear explosions should be restricted. Trees should be planted by the roadside, riverbanks, parks and open places as they keep the environment fresh. Pollution control laws should be strictly enforced.



Name: Shehu Nathaniel Adams & Dr. Daudu O.A. Yusuf

Level: 500

Department: Biological Sciences

School: Federal University of Technology Minna,

Niger state.

08076777877