Variability in VOC concentrations in an urban area of Delhi.

The variability of pollutants is an important factor in determining human exposure to the chemicals. This study presents the result of investigation of variability of Volatile organic compounds (VOCs) in urban area of Delhi, capital of India. Fifteen locations, in five categories namely residential, commercial, industrial, traffic intersections and petrol pump were monitored for one year every month during peak hours in morning and evening. Measurement focused on target VOCs as defined by USEPA. Variability was divided into measurement, spatial, temporal and temporal-spatial interaction components. Temporal component along with temporal-spatial interaction were found to be the major contributors to the variability of measured VOC concentrations. Need of continuous monitoring to capture short-term peak concentration and averages is evident.