Health Impacts
Air pollution has become a major concern in India in recent years as large parts of the Indian urban population is exposed to some of the highest pollutant levels in the world. All air pollutants are known or suspected to have harmful effects on human health and the environment. These pollutants are principally the products of combustion from industries or from motor vehicle traffic. In India, World Bank estimated 40,000 premature deaths in 1991 and Centre for Science and Environment estimated 52,000 premature deaths in 1995 due to SPM levels in ambient air. Specially, Calcutta, Delhi, Mumbai, Kanpur & Ahmedabad indicated very high numbers of premature deaths and have shown increasing trends when compared with 1991 figures. With that, nearly 2.5 crore sick cases were reported in 1995 in comparison to 1.9 crores in 1991. The burden of air pollution is suggested by the fact that every year in Delhi nearly 18600 people die prematurely because of exposure to particulate matter. (Pachauri and Sridharan (1998)). In the United States particulate have the greatest influence on daily deaths among persons 65 and older. In Delhi, they have the greatest impact in the 15 to 44 age group. (Alberini, Sharma, Simon, Cropper). Teri (1998) estimated the incidence of mortality and morbidity in different groups in India due to exposure to PM10 which indicated 2.5 million premature deaths. The prevalence of cancer is about 4.1% amongst all the disease indicating the effects of air pollution on urban population (CPCB 2000c)
Visibility Reduction
Visibility impairment is one of the major problems concerned with air pollution in major cities or industrial areas where the particulate matter concentration is quite high. Visibility impairment is basically the haze that obscures what we see, and is caused by the presence of tiny particles in the air. These particles cause light to be scattered or absorbed, thereby reducing visibility. The principal cause of visibility impairment is fine particles, primarily sulphates, but also nitrates, organics, and elemental carbon and crustal matter. Particles between 0.1 and one micrometers in size are most effective at scattering light, in addition to being of greatest concern for human health.
Vegetation Impacts
Gaseous air pollutants are found to affect crop plants detrimentally through direct visible injury, and/or effects on growth and yield (invisible injury), and through subtle physiological, chemical or anatomical changes.
Building or Material Damage
Deterioration of marble of Taj is the present example of the damaging effect of air pollution on the materials. The impacts of air pollution on structures and materials differ widely depending on the material. The major issue with respect to stone is the soiling and deterioration of limestone. Building exteriors and statues constructed of limestone materials are susceptible to particulate matter in urban smoke, which soils the structure, and to acid rain, which chemically attacks and deteriorates limestone. The major issue with respect to metals is corrosion of the surface, or the deterioration of the surface and loss of material due to oxidation of the metal (rust is an example of this).