US EPA

191328 

Journal Article 

Effects of air pollution on agriculture : An issue of national concern 

Agrawal, M 

2005 

1 

National Academy Science Letters
ISSN: 0250-541X
EISSN: 2250-1754 

28 

3-4 

93-106 

WOS:000229009400005 

The problem of air pollution has attracted special attention in India due to tremendous increase in size of population, industrialization and urbanization since last few decades. The major air pollutants of concern are identified as sulphur dioxide, nitrogen dioxide, ozone and particulate matter. Thermal power plants and transport sector is the biggest contributor of air pollution in the country. Ambient air around large industrial sources and metropolitan cities has already shown pollutant levels above the standards set by Central Pollution Control Board. India. Experimental studies conducted at Varanasi situated in upper Gangetic plains of India have indicated significant losses of agricultural production at current ambient pollutant levels in urban, suburban and rural areas. The intensity of losses, however, depends upon the pollutant concentration, duration of exposure. climatic and edaphic factors, plant species and cultivars. Pollutants either affect the plants directly by causing visible injury or indirectly growth or yield reductions without visible injury. Reductions in leaf area, biomass, chlorophyll, ascorbic acid and N contents have often been observed for the crop species growing in polluted area. Field transect studies have shown significant negative correlations between air pollutant concentrations and net photosynthesis, biomass accumulation and yield of crop plants. Monocot plants are found to be more resistant than dicot plants. Leguminous plants and leafy vegetables are most sensitive to air pollutants among the crop plants. Winter crops showed relatively lower magnitude of yield losses at different sites than summer crops. Quality of seeds also varied between urban, suburban and rural sites. Variations in nutrient, metabolite and energy contents of seeds directly corresponded to the levels of air pollutants at different sites. At urban and suburban sites, the magnitude of response involved all pollutants, whereas at rural site ozone had more influence. Ozone seems to play a major role in yield loss as maximum reductions in yield and quality of seeds were recorded at sites showing highest 03 concentrations. Simulation experiments conducted in closed top or open top chambers have also confirmed the adverse impacts of individual pollutants on plants. National ambient air quality standards are mainly based on health impact, hence a revision of the same taking into account climatic conditions; type of vegetation and soil is urgently required to save crops from adverse impacts of air pollution. Economic evaluation of crop loss due to air pollution is an important need of the future to secure food for growing population of the country. Long-term studies are required all along the country to identify the high and low risk zones of air pollution in different regions to develop control policy for reducing adversities of air pollution on vegetation. 

air pollution; agriculture; vegetation