Study of urban air quality in Kolkata for source identification and estimation of ozone, carbonyls, NOx and VOC emissions

Volatile Organic Compounds or VOCs play an important role in tropospheric chemistry by affecting the OH radical concentration, production of organic acids and photochemical oxidants. In order to develop efficient air pollution abatement strategies, it is important to know the sources and fate of VOCs, specially in the South-East Asian region where high level of solar irradiation favours photochemical ozone production. Individual compounds of non-methane hydrocarbons (NMHC) have different effects on ozone formation due to their different reaction rates and pathways. It is therefore important to identify the profiles of different VOCs in the atmosphere and their emission source for development of control programme. Central Pollution Control Board (CPCB) has carried out a study through NEERI to measure the levels of Ozone, VOCs including carbonyls in ambient air in the metropolitan city of Kolkata. The report presents findings of the study and recommendations for actions to be taken including the strategy for mitigation of VOCs.