A diverse range of sources like, domestic, industries and vehicles contribute to the airborne particulate matter observed in the urban atmosphere. Impact of growing number of vehicles, with a compounded annual growth rate of 15%, on air quality is evident.
The particles in gasoline and diesel vehicle exhaust carry distinctive combinations of certain chemical compounds. The prominence of their chemical signature in ambient particulate matter is thus a qualitative but direct indication of gasoline and diesel vehicles' relative importance as sources of emissions.
The vehicle emission profiles generated, by PM characterization together with the ambient particulate matter speciation data, could be a realistic input to the source apportionment study for identification of sources of air pollution.
As no data was available on PM10 emission profiles for vehicles plying in Indian cities, the need was felt to develop the vehicle exhaust profiles and estimate contribution of mobile sources in urban environment. This project was therefore aimed at development of vehicle source profiles for Indian vehicles to use in receptor model for source apportionment study.
A comprehensive data base on PM10 source profiles was generated on Indian vehicles comprising of two and three wheelers, cars, LCV, HCV from 1991 to post 2005 vintage with Gasoline/Diesel fuel as per applicable test methods.
The composite profiles for gasoline and diesel vehicle exhaust were prepared through detailed chemical speciation of vehicle exhaust particulate matter in ions, elements, carbon fractions and polycyclic aromatic hydrocarbons (PAHs).
Complete characterization of gasoline and diesel particulate matter from different categories and vintages of vehicles is presented in this paper. Higher fraction of elemental carbon was observed in diesel vehicles than in gasoline vehicle exhaust. However, % share of average organic carbon, % share of PAHs and ions in PM was observed to be higher in case of gasoline exhaust than in diesel exhaust.