Levels and sources of organic compounds in fine ambient aerosols over National Capital Region of India

Abstract

The study presents the spatial and temporal variation of fine ambient aerosols (PM) over National Capital Region (NCR), India, during January to June 2016. The investigation includes three sampling sites, one in Delhi and two in the adjoining states of Delhi (Uttar Pradesh and Haryana), across NCR, India. The average PM concentration was highest for Delhi (128.5 ± 51.5 μg m) and lowest for Mahendragarh, Haryana (74.5 ± 28.7 μg m), during the study period. Seasonal variation was similar for all the sites with highest concentration during winter and lowest in summer. PM samples were analysed for organic compounds using gas chromatograph (GC). The concentration of three organic compound classes, n-alkanes (C11-C35), polycyclic aromatic hydrocarbons (PAHs), and phthalates, present in PM samples has been reported. Diagnostic ratios for n-alkanes demonstrated that biogenic emissions were dominant over Mahendragarh while major contributions were observed from petrogenic emissions over Delhi and Modinagar, Uttar Pradesh. Molecular diagnostic ratios were calculated to distinguish between different sources of PAHs, which revealed that the fossil fuel combustion (diesel and gasoline emissions), traffic emissions, and biomass burning are the major source contributors. Health risk associated with human exposure of phthalates and PAHs was also assessed as daily intake (DI, ng kg day) and lung cancer risk, respectively. Backward trajectory analysis explained the local, regional, and long-range transport routes of PM for all sites. Principal component analysis (PCA) results summarized that the vehicular emissions, biomass burning, and plastic burning were the major sources of the PAHs and phthalates over the sampling sites.

In situ Ozone Production is highly sensitive to Volatile Organic Compounds in the Indian Megacity of Delhi

“…Alkanes were the predominant VOC class contributing to the total measured VOC mass concentration (42 %), consistent with previous observations at the site (Shivani et al, 2018), followed by alcohols (18 %), aromatics (17.8 %) and carbonyls (13.9 %). The percentage contributions of each VOC class to total measured VOCs, along with mean mass concentrations of the top 10 contributors, are presented in figure 5.…”

Identification of Carbonaceous Species and FTIR Profiling of PM2.5 Aerosols for Source Estimation in Old Delhi Region of India

“…The filters (QFFs) were routinely desiccated for 24 h before and after sample loading, and stored at – 27 °C till analysis. The sampling protocol, data quality assurance, and control measures were adopted from the previous work [ 3 , 4 , 37 , 38 , 42 – 46 ]. Four representative samples in each month ( n = 4) of the study period were selected for FTIR and OC–EC analyses.…”

Gridded distribution of total suspended particulate matter (TSP) and their chemical characterization over Delhi during winter

“…Principle components to be retained were decided by examining the screen plot and percent of the variance. PCs that have eigenvalue > 1 divide the data into groups and were considered for further analysis for source identi cation (Hazarilka et al 2015;Shivani et al 2018). Factor 1 (PC1) contained high loading of Mg, Fe, K, Al, Na, Cl, Ca, Ti, and OC with 32.4% of variance which indicates the major contribution of crustal/soil dust as these are soil-related crustal elements (Jain et al 2017;Srivastava and Jain.…”