Remarkably High Oxidative Potential of Atmospheric PM2.5 Coming from a Large-Scale Paddy-Residue Burning over the Northwestern Indo-Gangetic Plain

Abstract. The large-scale emissions of airborne particulates from burning of agricultural residues particularly over the upper Indo-Gangetic Plain (IGP) have often been associated with frequent formation of haze, adverse health impacts, modification in aerosol climatology and thereby aerosols impact on regional climate. In this study, short-term variations in aerosol climatology during extreme biomass burning emissions over IGP, and thereby to regional climate were investigated. Size-segregated particulate concentration was initially measured and submicron particles (PM1.1) were found to dominate particulate mass within the fine mode (PM2.1). Particulate bound water-soluble ions were mainly secondary in nature, primarily composed of sulfate and nitrate. There was evidence of gaseous NH3 dominating neutralization of acidic aerosol species (SO42−) in submicron particles, in contrast to crustal dominating neutralization in coarser particulates. Variation in black carbon mass ratio was found to be influenced by local sources, while sudden increase in concentration was consistent with high Delta-C, referring to biogenic emissions. Influence of biomass burning emissions were established using specific organic (levoglucosan), inorganic (K+ and NH4+) and satellite (UV Aerosol Index, UVAI) tracers. Levoglucosan was the most abundant within submicron particles (649±177 ng m−3), with a very high ratio (>50) against other anhydrosugars, indicating exclusive emissions from burning of agriculture residues. Temporal variations of all the tracers were consistent, while NH4+ was more closely associated to levoglucosan. Spatio-temporal distribution of aerosol and few trace gases (CO and NO2) were evaluated using both space-borne active and passive sensors, and a significant increase in columnar aerosol loading (AOD: 0.98) was evident during extreme biomass burning emissions, with presence of absorbing aerosols (UVAI > 1.5) having low aerosol layer height (~1.5 km). A strong intraseasonality in aerosol cross-sectional altitudinal profile was even noted from CALIPSO, referring dominance of smoke and polluted continental aerosols across IGP. Possible transport mechanism of biomass smoke was established using cluster analysis and concentration weighted of air mass back-trajectories. Short-wave aerosol radiative forcing (ARF) was further simulated considering intraseasonality in aerosol properties, which resulted in considerable increase of atmospheric ARF (135 Wm−2) and heating rate (4.3 K day−1) during extreme biomass burning emissions compared to non-dominating one (56 Wm−2, 1.8 K day−1). We therefore conclude that influence of biomass burning emissions on regional aerosol climatology must need to be studied in much finer scale to improve parameterization of aerosol/-climate model across the region.

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Oxidative potential of ambient fine aerosol over a semi-urban site in the Indo-Gangetic Plain

Atmospheric Environment ◽

10.1016/j.atmosenv.2017.12.004 ◽

2018 ◽

Vol 175 ◽

pp. 127-134 ◽

Cited By ~ 21

Author(s):

Anil Patel ◽

Neeraj Rastogi

Keyword(s):

Urban Site ◽

Oxidative Potential ◽

Gangetic Plain ◽

Fine Aerosol ◽

Indo Gangetic Plain

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Temporal Trends in Atmospheric PM2.5, PM10, Elemental Carbon, Organic Carbon, Water-Soluble Organic Carbon, and Optical Properties: Impact of Biomass Burning Emissions in The Indo-Gangetic Plain

Environmental Science & Technology ◽

10.1021/es202857w ◽

2012 ◽

Vol 46 (2) ◽

pp. 686-695 ◽

Cited By ~ 108

Author(s):

Kirpa Ram ◽

M. M. Sarin ◽

S. N. Tripathi

Keyword(s):

Optical Properties ◽

Organic Carbon ◽

Elemental Carbon ◽

Temporal Trends ◽

Water Soluble ◽

Gangetic Plain ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon ◽

Indo Gangetic Plain ◽

Atmospheric Pm2.5

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Particulate Oxidative Potential (OP) Associated with Fireworks Activity during Diwali at a site in the Indo-Gangetic Plain

10.21203/rs.3.rs-843806/v1 ◽

2021 ◽

Author(s):

Anita Lakhani ◽

Isha Goyal ◽

Puneet Kumar Verma ◽

Kandikonda Maharaj Kumari

Keyword(s):

Hazard Index ◽

Chemical Species ◽

Positive Association ◽

Ambient Air ◽

Ros Generation ◽

Oxidative Potential ◽

Gangetic Plain ◽

Diwali Festival ◽

A Site ◽

Indo Gangetic Plain

Abstract The potential of the atmospheric fine aerosols (PM2.5) to generate reactive oxygen species (ROS) during firework activity in Diwali festival was assessed by the dithiothreitol (DTT) assay at a site in the Indo-Gangetic Plain, India. The 12-h mean PM2.5 was found to be 262.9 ±150.7 µg m-3 during the study period which was 4.4 times exceeded the NAAQS limits. Firework activity was also characterized by increased levels of gaseous pollutants (NOx, SO2, CO and O3), and trace metal concentrations like Ba, Pb, Cu, Fe, Mg, K, Al and Mn. Elevated PM2.5-NOx slope for fireworks including traffic emissions suggested significant contribution of fireworks. The highest value of PM ROS activity, volume-based DTT value was 1.37 nmol min-1 m-3 and mass-based DTT value was 11.77 pmol min-1 μg-1, found in the next morning of Diwali, suggesting stronger PM associated ROS activity due to fireworks. A positive association was found between redox-active metals like Cd, Cr, Cu, Ni, and V and DTT activity that could be due to the ability of these metals to catalyze ROS generation in ambient air, while Ba, Be and Se in atmosphere as major constituents of firecrackers were also strongly associated with DTT activity. The ozone levels were strongly correlated (r2 = 0.87) with DTTv activity during daytime due to photochemical activities including chemical species associated with fireworks responsible for forming tropospheric O3. Comparison of the daily DTTv activity and hazard index (HI) suggests that the HI may be a poor metric to measure the health effects by which PM exposure can induce deterioration in human health.

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Aerosol chemistry, transport, and climatic implications during extreme biomass burning emissions over the Indo-Gangetic Plain

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-14197-2018 ◽

2018 ◽

Vol 18 (19) ◽

pp. 14197-14215 ◽

Cited By ~ 26

Author(s):

Nandita Singh ◽

Tirthankar Banerjee ◽

Made P. Raju ◽

Karine Deboudt ◽

Meytar Sorek-Hamer ◽

...

Keyword(s):

Biomass Burning ◽

Radiative Forcing ◽

Large Scale ◽

Water Soluble ◽

Submicron Particles ◽

Aerosol Layer ◽

Aerosol Chemistry ◽

Short Term ◽

Gangetic Plain ◽

Indo Gangetic Plain

Abstract. The large-scale emissions of airborne particulates from burning of agricultural residues particularly over the upper Indo-Gangetic Plain (IGP) have often been associated with frequent formation of haze, adverse health impacts, and modification in aerosol climatology and thereby aerosol impact on regional climate. In this study, short-term variations in aerosol climatology during extreme biomass burning emissions over the IGP were investigated. Size-segregated particulate concentration was initially measured and submicron particles (PM1.1) were found to dominate particulate mass within the fine mode (PM2.1). Particulate-bound water-soluble ions were mainly secondary in nature and primarily composed of sulfate and nitrate. There was evidence of gaseous NH3 dominating neutralization of acidic aerosol species (SO42-) in submicron particles, in contrast to crustal-dominating neutralization in coarser particulates. Diurnal variation in black carbon (BC) mass ratio was primarily influenced by regional meteorology, while gradual increase in BC concentration was consistent with the increase in Delta-C, referring to biomass burning emissions. The influence of biomass burning emissions was established using specific organic (levoglucosan), inorganic (K+ and NH4+), and satellite-based (UV aerosol index, UVAI) tracers. Levoglucosan was the most abundant species within submicron particles (649±177 ng m−3), with a very high ratio (> 50) to other anhydrosugars, indicating exclusive emissions from burning of agriculture residues. Spatiotemporal distribution of aerosol and a few trace gases (CO and NO2) was evaluated using both spaceborne active and passive sensors. A significant increase in columnar aerosol loading (aerosol optical depth, AOD: 0.98) was evident, with the presence of absorbing aerosols (UVAI > 1.5) having low aerosol layer height (∼ 1.5 km). A strong intraseasonality in the aerosol cross-sectional altitudinal profile was even noted from CALIPSO, referring to the dominance of smoke and polluted continental aerosols across the IGP. A possible transport mechanism of biomass smoke was established using cluster analysis and concentration-weighted air mass back trajectories. Short-wave aerosol radiative forcing (ARF) was further simulated considering intraseasonality in aerosol properties, which resulted in a considerable increase in atmospheric ARF (135 W m−2) and heating rate (4.3 K day−1) during extreme biomass burning emissions compared to the non-dominating period (56 W m−2, 1.8 K day−1). Our analysis will be useful to improve understanding of short-term variation in aerosol chemistry over the IGP and to reduce uncertainties in regional aerosol–climate models.

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Deposition of light-absorbing particles in glacier snow of the Sunderdhunga Valley, the southern forefront of Central Himalaya

10.5194/acp-2020-1059 ◽

2020 ◽

Author(s):

Jonas Svensson ◽

Johan Ström ◽

Henri Honkonen ◽

Eija Asmi ◽

Nathaniel B. Dkhar ◽

...

Keyword(s):

Large Scale ◽

Anthropogenic Activities ◽

Central Himalaya ◽

Snow Layer ◽

Gangetic Plain ◽

Central Himalayas ◽

Indo Gangetic Plain ◽

The Himalaya ◽

Very High ◽

Fractional Absorption

Abstract. Anthropogenic activities on the Indo-Gangetic Plain emit vast amounts of light-absorbing particles (LAP) into the atmosphere, modifying the atmospheric radiation scheme. With transport to the nearby Himalayan mountains and deposition to its surfaces the particles contribute to glacier and snowmelt via darkening of the highly reflective snow. The Central Himalayas have been identified as a region where LAP are especially pronounced in glacier snow, but still remain a region where measurements of LAP in the snow are scarce. Here we study the deposition of LAP in five snow pits sampled in 2016 (and one from 2015) from two glaciers in the Sunderdhunga valley, state of Uttarakhand, India, Central Himalaya. The snow pits display a distinct melt layer interleaved by younger snow above, and older snow below. The LAP exhibit a large vertical distribution in these different snow layers. For the analyzed elemental carbon (EC), the younger snow layers in the different pits show similarities, and can be characterized by a deposition constant of about 50 µg m−2 mm−1 while the old snow layers also indicate similar values, and can be described with deposition constant of roughly 150 µg m−2 mm−1. The melt layer, contrarily, display no similar trends between the pits. Instead, it is characterized by very high amounts of LAP, and differ in orders of magnitude for concentration between the pits. The melt layer is likely a result of strong melting that took place during the summers of 2015 and 2016. The mineral dust fractional absorption is slightly below 50 % for the young and old snow layer, whereas in the melt layer is the dominating light absorbing constituent, thus, highlighting the importance of dust in the region. Our results indicate the problems with complex topography in the Himalaya, but nonetheless, can be useful in large-scale assessments of LAP in Himalayan snow.

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Deposition of light-absorbing particles in glacier snow of the Sunderdhunga Valley, the southern forefront of the central Himalayas

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-2931-2021 ◽

2021 ◽

Vol 21 (4) ◽

pp. 2931-2943

Author(s):

Jonas Svensson ◽

Johan Ström ◽

Henri Honkanen ◽

Eija Asmi ◽

Nathaniel B. Dkhar ◽

...

Keyword(s):

Large Scale ◽

Elemental Carbon ◽

Snow Water Equivalent ◽

Anthropogenic Activities ◽

Gangetic Plain ◽

Central Himalayas ◽

Snow Water ◽

Indo Gangetic Plain ◽

Very High ◽

Fractional Absorption

Abstract. Anthropogenic activities on the Indo-Gangetic Plain emit vast amounts of light-absorbing particles (LAPs) into the atmosphere, modifying the atmospheric radiation state. With transport to the nearby Himalayas and deposition to its surfaces the particles contribute to glacier melt and snowmelt via darkening of the highly reflective snow. The central Himalayas have been identified as a region where LAPs are especially pronounced in glacier snow but still remain a region where measurements of LAPs in the snow are scarce. Here we study the deposition of LAPs in five snow pits sampled in 2016 (and one from 2015) within 1 km from each other from two glaciers in the Sunderdhunga Valley, in the state of Uttarakhand, India, in the central Himalayas. The snow pits display a distinct enriched LAP layer interleaved by younger snow above and older snow below. The LAPs exhibit a distinct vertical distribution in these different snow layers. For the analyzed elemental carbon (EC), the younger snow layers in the different pits show similarities, which can be characterized by a deposition constant of about 50 µg m−2 mm−1 snow water equivalent (SWE), while the old-snow layers also indicate similar values, described by a deposition constant of roughly 150 µg m−2 mm−1 SWE. The enriched LAP layer, contrarily, displays no similar trends between the pits. Instead, it is characterized by very high amounts of LAPs and differ in orders of magnitude for concentration between the pits. The enriched LAP layer is likely a result of strong melting that took place during the summers of 2015 and 2016, as well as possible lateral transport of LAPs. The mineral dust fractional absorption is slightly below 50 % for the young- and old-snow layers, whereas it is the dominating light-absorbing constituent in the enriched LAP layer, thus, highlighting the importance of dust in the region. Our results indicate the problems with complex topography in the Himalayas but, nonetheless, can be useful in large-scale assessments of LAPs in Himalayan snow.

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Growth in mid-monsoon dry phases over the Indian region: prevailing influence of anthropogenic aerosols

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-12325-2019 ◽

2019 ◽

Vol 19 (19) ◽

pp. 12325-12341 ◽

Cited By ~ 1

Author(s):

Rohit Chakraborty ◽

Bijay Kumar Guha ◽

Shamitaksha Talukdar ◽

Madineni Venkat Ratnam ◽

Animesh Maitra

Keyword(s):

Large Scale ◽

Potential Evapotranspiration ◽

Southern Oscillation ◽

Monsoon Season ◽

Anthropogenic Aerosols ◽

Gangetic Plain ◽

Rcp 8.5 ◽

Urbanized Region ◽

Indo Gangetic Plain

Abstract. A detailed investigation on the potentially drought-prone regions over India is presented in this study based on the balance between precipitation and potential evapotranspiration (PET) during the southwest Asian mid-monsoon season. We introduce a parameter named dry day frequency (DDF) which is found suitable to present the drought index (DI) in mid-monsoon season, hence strongly associated with the possibility of drought occurrences. The present study investigates the probable aspects which influence the DDF over these regions, revealing that the abundance of anthropogenic aerosols especially over urbanized locations has a prevailing role in the growth of DDF during the last few decades. The prominent increasing trend in DDF over Lucknow (26.84∘ N, 80.94∘ E), a densely populated urban location situated in the Indo-Gangetic Plain, strongly reflects the dominant association of anthropogenic aerosols with the increasing dry phase occurrences. Increase in DDF (∼90 %) during the last 60 years is observed over this urban area compared to a broader region in its surroundings. In addition, periodic impacts of large-scale phenomena like ENSO (El Niño–Southern Oscillation) or SSN (sunspot number) become weaker when the study location is downscaled towards an urbanized region. Finally, when long-term projections of DDF are drawn using the high urbanization scenario of RCP 8.5, a huge rise in dry days is seen during mid-July to mid-September (reaching up to 50 dry days by the year 2100 over Lucknow), which will be a crucial concern for policymakers in future.

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