Volatile Organic Compounds (VOCs) in Ambient Air - A Case Study at the Vicinity of Fuel Filling Stations in New Delhi, India

Volatile Organic Compounds (VOCs) present in ambient air are potentially toxic among the air pollutants. They are present in the urban atmosphere due to both exhaust emissions from vehicles and evaporative emissions at fuel filling stations. The present study aims to provide an indication of ambient levels of benzene, a carcinogenic VOC in the immediate vicinity of petrol filling stations in Delhi & National Capital Region (NCR). The monitoring of benzene is conducted across the vicinity of petrol stations to ascertain the effect of outside pollutant concentration on forecourt area. Continuous monitoring of benzene was achieved by an air quality monitoring facility stationed across the selected locations at four selected fuel filling stations. It was observed that the average concentrations of benzene measured during the study ranged between 2.28 ppb - 9.43 ppb. The study also reveals few peaks in the benzene level during heavy traffic count and these values were higher than the limiting value of 1.56 ppb as prescribed by NAAQS (National Ambient Air Quality Standard) of India. The temporal variation in the concentration of benzene depicts high levels during busy traffic intersection and comparatively low values during non-peak hours. It can be concluded that thorough source apportionment studies must be undertaken before the implementation of superior technologies i.e., control measure techniques like Vapor Recovery Systems, On-baord Re-fuelling Vapor Recovery etc.