Chemical characterization, source apportionment and transport pathways of PM2.5 and PM10 over Indo Gangetic Plain of India

Abstract

The present work depicts the spatial and temporal variations in chemical characteristics and sources of PM2.5 and PM10 over Indo Gangetic Plain (IGP) of India from January 2015 to December 2016. PM2.5 and PM10 samples were collected at three typical urban sites of Delhi, Varanasi, and Kolkata of IGP, India and characterized to evaluate their chemical components. The average concentrations of PM2.5 at Delhi, Varanasi, and Kolkata were 135 ± 64, 99 ± 33, and 116 ± 38 μg m−3, respectively. Whereas the average concentrations of PM10 over Delhi, Varanasi, and Kolkata were 242 ± 95, 257 ± 90, and 179 ± 77 μg m−3, respectively. Source apportionment was carried out using the three receptor models i.e. Principal Component Analysis-Absolute Principal Component Score (PCA-APCS), UNMIX, and Positive Matrix Factorization (PMF), implemented on the same data sets to obtain the conjointly validated results. All the models identified that vehicular emissions, secondary aerosols, biomass burning, and soil dust were the dominant sources of PM2.5 and PM10 over IGP, India. Hybrid receptor models revealed the presence of strong local emission sources as well as traversing of pollutants from the parts of Pakistan, Punjab, Haryana, Rajasthan, Uttar Pradesh, Bihar, and Bangladesh.