Volatile organic compounds in ambient air of Mumbai—India

Volatile organic compounds (VOCs) are a major group of air pollutants which play a critical role in atmospheric chemistry. These contribute to toxic oxidants which are harmful to ecosystem, human health and atmosphere. The variability of pollutants is an important factor in determining human exposure to these chemicals. Data on levels of VOCs in developing countries, including India, are lacking. The present work deals with the estimation of target VOCs at 15 locations of five categories in Mumbai. The categories are residential, industrial, commercial, traffic intersections and petrol refueling stations. The monitoring was carried out during peak hours in the morning and evening, once every month, during May 2001 to April 2002. The study focused on target VOCs as defined by USEPA. Concentrations of benzene, at all the locations, were found to be much above the guidelines values prescribed by World Health Organization (WHO) for ambient air quality. All other VOCs were observed to be below the WHO guideline values. The results show that levels of VOCs in Mumbai were high. There is need for a regular monitoring schedule of VOCs in the urban environment. Variability studies are important to assess the exposure potential of pollutants which are an important parameter for health impact studies. This study also presents the variability of VOCs in the urban area of Mumbai. Variability was divided into measurement spatial, temporal and temporal–spatial interaction components. The temporal component along with temporal–spatial interaction component were the major contributors to variability. VOCs associated with mobile source emissions and emissions from marine source were found to be distributed uniformly in the urban atmosphere in Mumbai. the need for continuous monitoring, to capture short term peak concentrations and averages, is evident