Chemical characterisation and source apportionment of PM₁ during massive loading at an urban location in Indo-Gangetic Plain: impact of local sources and long-range transport

Abstract

A B S T R A C TThis study assesses temporal variability and source contributions of PM 1 (particles with aerodynamic diameter 5 1.0 mm) samples (n051; November 2009ÁFebruary 2010) from an urban location at Kanpur (26.308N; 80.138E; 142 m above mean sea-level) in the Indo-Gangetic Plain (IGP). A study period from November to February is preferred owing to massive loading of particulate matter in entire IGP. PM 1 varies from 18 to 348 (Avg9SD: 113972) mg m (3 in this study. A total of 11 trace metals, five major elements and four water-soluble inorganic species (WSIS) have been measured. Mass fraction of total metals (ametals 0 tratrace ' major) centres at 18914 %, of which nearly 15 % is contributed by major elements. Furthermore, aWSIS contributes about 26 % to PM 1 mass concentration. Abundance pattern among assessed WSIS in this study follows the order: NH 4 ' :SO 4 2 ( ! NO 3 ( ! Cl ( . The K-to-PM 1 mass fraction (Avg: 2 %) in conjunction with air-mass back trajectories (AMBT) indicates that the prevailing north-westerly winds transport biomass burning derived pollutants from upwind IGP. A recent version of positive matrix factorisation (PMF 5.0) has been utilised to quantify the contribution of fine-mode aerosols from various sources. The contribution from each source is highly variable and shows a strong dependence on AMBT. Events with predominant contribution from biomass burning emission ( !70 %) indicate origin of air-masses from source region upwind in IGP. One of the most interesting features of our study relates to the observation that secondary aerosols (contributing as high as Â60 % to PM 1 loading) are predominantly derived from stationary combustion sources (NO 3 ( /SO 4 2 ( ratio: 0.3090.23). Thus, our study highlights a high concentration of PM 1 loading and atmospheric fog prevalent during wintertime can have a severe impact on atmospheric chemistry in the air-shed of IGP.

OM/OC Ratio of Polar and Non-Polar Organic Matter during Wintertime from Indo-Gangetic Plain: Implications to Regional-Scale Radiative Forcing

“…The average NO 3 − /SO 4 2− mass ratio < 1 can be attributed to predominant impact from stationary source/s (biomass burning, coal combustion and industrial emission), whereas the NO 3 − /SO 4 2− mass ratio ≥ 1 indicates predominant impact from mobile source (vehicular emissions) (Wu et al 2017). A recent study based on positive matrix factorization (PMF) has reported similar results with the NO 3 − /SO 4 2− mass ratio in IGP (Rajput et al 2016b).…”

“…9a) suggested that NH 4 + was in excess. In this context, previous studies have reported that excess NH 4 + can lead to uptake of NO 3 − in the particulate phase (Pathak et al 2009;Rajput et al 2016b). Furthermore, the NO 3 − /SO 4 2− average mass ratio was 0.71 ± 0.33 in this study (Fig.…”

Spatiotemporal variation of PM1 pollution in China

“…Unlike PM 2.5 and PM 10 , PM 1 originates almost entirely from two sources: direct emissions 97 during combustion process, and indirectly, from formation of particles in the air from gaseous 98 precursors (Rajput et al, 2016;Singhai et al, 2016). By contrast, PM 10 is mostly emitted by 99 mechanical processes, such as construction activities, or by wind re-suspension (of for 100 example loose soil).…”

Synergistic effect in absorption properties of brown carbon and elemental carbon over IGP during weak south-west monsoon

“…Concentration of K ? in aqueous extracts has been measured on an ionchromatograph (Metrohm) (Chakraborty and Gupta 2010;Gupta and Mandaria 2013;Rajput et al 2016b). To assess the quality control of data, blank filters (n = 4) were simultaneously processed and analyzed along with aerosol samples in the similar manner.…”

“…It should be noted that herein synergy represents the lensing effect between BrC (shell/coating) and EC (core) aerosols. The IGP is stretched from north-west to north-east region in India, which is considered as one of the most polluted and populated regions of the world (Kaul et al 2011;Rajput et al 2011Rajput et al , 2013Rajput et al , 2015Rajput et al , 2016b. This study was strategically conducted over central IGP during a monsoon season (July-September 2015) influenced by El Niño and PDO.…”