Estimation of Carbonaceous Emission Impact on Urban Soil-Dust in Delhi

It is well established that mineral dust is responsible for high levels of particulates in the air over North India. Mixing of dust with anthropogenic air pollutants influences the optical properties of the atmosphere affecting the visibility, biogeochemistry, local climate and air quality. Strong interaction of carbonaceous aerosols with mineral dust further facilitates such phenomenon. Carbonaceous components such as organic carbon (OC) and elemental carbon (EC) play significant role in regional and global climate by altering the radiation budget of the surface, whereas carbonate carbon (CC) helps in buffering the atmospheric acidity. In order to investigate such interactions, this paper presents the concentrations of different carbonaceous components in atmospheric dust and soil at three sites in the National Capital Region of Delhi. Results showed that high levels of carbonaceous components and their spatial distribution had close correspondence with local anthropogenic activities such as vehicular emission, biomass burning, crustal components from exposed land surfaces, construction activities, etc. High OC and EC enrichment in dust as compared to soil have suggested their abundance in urban dust due to the significant interaction of atmospheric dust with urban anthropogenic emissions of EC and OC. The estimation of carbonaceous fractions in soil and dust filter samples had high accuracy due to matrix match standard was developed to quantify the content. Recovery of 98% was achieved for a synthetic mixture of charcoal and carbonate representing the matrix of real samples. The study demonstrated that abundance of carbonaceous components in atmospheric dust is an effective indicator of pollution from increased human activities in urban areas.