Influence of agricultural activities on atmospheric pollution during post-monsoon harvesting seasons at a rural location of Indo-Gangetic Plain

2021 ◽  
pp. 148903
Author(s):  
Tanbir Singh ◽  
Khaiwal Ravindra ◽  
Gufran Beig ◽  
Suman Mor
Keyword(s):  
Atmospheric Pollution ◽  
Agricultural Activities ◽  
Gangetic Plain ◽  
Rural Location ◽  
Post Monsoon ◽  
Indo Gangetic Plain

Aerosol acidity and its neutralization in the eastern Indo-Gangetic Plain: implications for water-soluble organic carbon

2020 ◽  
Author(s):  
Bijay Sharma ◽  
Anuraag J. Polana ◽  
Prashant Rawat ◽  
Sayantan Sarkar
Keyword(s):  
Receptor Site ◽  
Water Soluble ◽  
Dual Function ◽  
Gangetic Plain ◽  
Desert Dust ◽  
Post Monsoon ◽  
Aerosol Acidity ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Indo Gangetic Plain

<p>Aerosol acidity plays an important role in influencing precipitation pH, which has impacts on the environment as well as human health. It also has significance in shaping aerosol chemistry, including the catalytic formation of water-soluble organic carbon (WSOC), which in turn affects the hygroscopicity of aerosols. Past studies on aerosol acidity in the Indian subcontinent, mostly conducted in biomass burning (BB) source regions in the northwestern and central Indo-Gangetic Plain (IGP) and in western India, have identified Ca<sup>2+</sup> and Mg<sup>2+</sup> sourced from desert dust to be the predominant neutralizing agents. However, the prevalence of desert dust decreases progressively along the IGP corridor and is potentially rendered insignificant in the eastern IGP (eIGP). As such, there exists a critical weakness in our understanding of the processes governing aerosol acidity and its neutralization in the eIGP. To address this, the present study reports the seasonal variability of ionic species, WSOC and associated aerosol acidity in ambient PM<sub>2.5</sub> from a rural receptor site in the eIGP. To this end, a total of 88 PM<sub>2.5</sub> samples collected during the summer, post-monsoon and winter seasons of 2018 were analyzed for SO<sub>4</sub><sup>2-</sup>, NO<sub>3</sub><sup>-</sup>, Cl<sup>-</sup>, Na<sup>+</sup>, NH<sub>4</sub><sup>+</sup>, K<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, F<sup>-</sup>, PO<sub>4</sub><sup>3-</sup> and WSOC, followed by estimation of strong acidity. Across all seasons, the aerosol phase was dominated by SO<sub>4</sub><sup>2-</sup>, NH<sub>4</sub><sup>+</sup> and NO<sub>3</sub><sup>-</sup>, with values increasing by factors of 1.8-1.9, 1.4-2.9 and 1.8-11, respectively, for the regional BB-dominated post-monsoon and winter seasons as compared to summer. Significant positive Cl<sup>-</sup> depletion in summer pointed towards the influx of marine air while negative depletion in post-monsoon and winter suggested a BB source, which was further supported by concentration-weighted trajectory analysis. The averaged pH of the aerosol extract decreased progressively from summer (5.5±0.4) to winter (4.5±0.2). NH<sub>4</sub><sup>+</sup> was observed to be the major acid-neutralizing agent across all seasons, with dust-derived Ca<sup>2+</sup> and Mg<sup>2+</sup> playing only minor roles. In general, WSOC formation is known to be catalyzed by the presence of excess acidity; however, during winter, it appeared that the regional transport of organic acids in the BB plume contributed to aerosol acidity at this receptor site (r=0.92; p<0.01 for WSOC and H<sup>+</sup>). BB-derived K<sup>+</sup> appeared to perform a dual function of neutralizing acidity as well as producing it via reactions with WSOC during atmospheric transport. The wintertime acidity was also strongly governed by aerosol NO<sub>3</sub><sup>-</sup> sourced from BB emissions and possibly accentuated via nighttime atmospheric chemistry at lower ambient temperatures, resulting in the formation of haze. These observations of the NO<sub>3</sub><sup>-</sup> and WSOC-driven wintertime acidity, the dual function of K<sup>+</sup> and the dominant role of NH<sub>4</sub><sup>+</sup> in neutralization points to complex atmospheric processing of the IGP outflow during its transport to the eastern end of the corridor, which warrants further investigation.</p>

Variation in carbonaceous and ionic species at a rural receptor location in the eastern Indo-Gangetic Plain

2021 ◽  
Author(s):  
Bijay Sharma ◽  
Anurag J. Polana ◽  
Jingying Mao ◽  
Shiguo Jia ◽  
Sayantan Sarkar
Keyword(s):  
Organic Carbon ◽  
Forest Fires ◽  
Ionic Species ◽  
Water Soluble ◽  
Photochemical Oxidation ◽  
Carbonaceous Aerosol ◽  
Charge Ratio ◽  
Gangetic Plain ◽  
Post Monsoon ◽  
Indo Gangetic Plain

<p>The Indo-Gangetic Plain (IGP) is one of the world’s most populated river basins housing more than 700 million people. Apart from being a major source region of aerosols, the IGP is affected by transported aerosols from the Thar Desert, forest-fires and open burning of crop waste from central India. Studies have been carried out to understand the aerosol chemical composition and optical properties in source regions of IGP but knowledge is severely lacking for receptor locations viz. eastern IGP (eIGP). To address this, the present study reports the seasonal variability of carbonaceous and ionic species in ambient PM<sub>2.5</sub> from a rural receptor location (Mohanpur, West Bengal) along with insights on aerosol acidity, its neutralization and potential source regimes. A total of 88 PM<sub>2.5</sub> samples collected during the summer, post-monsoon and winter seasons of 2018 were analyzed for SO<sub>4</sub><sup>2-</sup>, NO<sub>3</sub><sup>-</sup>, Cl<sup>-</sup>, Na<sup>+</sup>, NH<sub>4</sub><sup>+</sup>, K<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, F<sup>-</sup>,<sup></sup>PO<sub>4</sub><sup>3-</sup>, water-soluble organic carbon (WSOC), organic carbon (OC) and elemental carbon (EC) fractions. Sulfate, nitrate and ammonium (SNA) were the dominating ionic species throughout the seasons (67-86% out of the total ionic species measured). Significant positive Cl<sup>-</sup> depletion in summer (49±20%) pointed towards influx of marine air while negative depletion in post-monsoon and winter suggested a biomass burning (BB) source, which was further supported by concentration-weighted trajectory analysis. Strong acidity was found to be highest during post-monsoon (141±76 nmol m<sup>-3</sup>), followed by winter (117±36 nmol m<sup>-3</sup>) and summer (40±14 nmol m<sup>-3</sup>) with significant differences between summer and the other seasons. Neutralization factor (N<sub>f</sub>) and equivalent charge ratio of cation to anion (R<sub>C/A</sub>) revealed that summertime aerosols were neutral in nature while those of post-monsoon and winter were comparatively acidic with NH<sub>4</sub><sup>+</sup> being the major neutralizing agent throughout the seasons. Correlations between WSOC and OC fractions (OC1, OC2, OC3 and OC4) suggested secondary formation of summertime WSOC (WSOC vs OC3: r=0.48, p<0.05) via photochemical oxidation of volatile organic carbons (VOCs) while that of post-monsoon (WSOC vs OC1, OC2, OC3: r=0.45-0.62, <em>p</em><0.05) and winter (WSOC vs OC1, OC2, OC3: r=0.58-0.68, <em>p</em><0.05), both primary and secondary pathways seem important. To elucidate the role of BB, we looked into the two components of EC i.e., char-EC (EC1-PC) and soot-EC (EC2+EC3). The percent contribution of char-EC to EC was 65±17%, 90±10% and 98±1% during summer, post-monsoon and winter, respectively. Along with this, char-EC/soot-EC ratios of 2.3±1.8, 17.6±16.4 and 50.3±18.6 during summer, post-monsoon and winter, respectively, and significant correlations of the same with the BB-tracer K<sup>+</sup> (post-monsoon: r=0.78, <em>p</em><0.001; winter: r=0.64, <em>p</em><0.01) indicated the importance of BB emissions in constraining carbonaceous aerosol profiles during post-monsoon and winter.</p>

scholarly journals Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: Influence of biomass burning

2017 ◽  
Author(s):  
Xin Wan ◽  
Shichang Kang ◽  
Quanlian Li ◽  
Dipesh Rupakheti ◽  
Qianggong Zhang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Vanillic Acid ◽  
Monsoon Season ◽  
Syringic Acid ◽  
Rural Site ◽  
Aerosol Composition ◽  
Gangetic Plain ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
Indo Gangetic Plain

Abstract. To better understand the characteristics of biomass burning in the northern Indo-Gangetic Plain (IGP), total suspended particles were collected in a rural site, Lumbini, Nepal during April 2013 to March 2014 and analyzed for the biomass burning tracers (i.e., levoglucosan, mannosan, vanillic acid, etc.). The annual average concentration of levoglucosan was 734 ± 1043 ng m−3 with the maximum seasonal mean concentration during post-monsoon season (2206 ± 1753 ng m−3), followed by winter (1161 ± 1347 ng m−3), pre-monsoon (771 ± 524 ng m−3) and minimum concentration during monsoon season (212 ± 279 ng m−3). The other biomass burning tracers (mannosan, galactosan, p-hydroxybenzoic acid, vanillic acid, syringic acid, and dehydroabietic acid) also showed the similar seasonal variations. There were good correlations among levoglucosan, organic carbon (OC) and elemental carbon (EC), indicating significant impact of biomass burning activities on carbonaceous aerosol loading throughout the year in Lumbini area. According to the characteristic ratios: levoglucosan / mannosan (Lev / Man) and syringic acid / vanillic acid (Syr / Van), we deduced that the high abundances of biomass burning products during non-monsoon seasons were mainly caused by the burning of crop residues and hardwood while the softwood had less contribution. Based on the diagnostic tracer ratio (i.e., Lev / OC), the OC derived from biomass burning constituted large fraction of total OC, especially during post-monsoon season. By analyzing the MODIS fire spot product and five-day air-mass back trajectories, we further demonstrated that organic aerosol composition was not only related to the local agricultural activities and residential biomass usage, but was also impacted by the regional emissions. During the post-monsoon season, the emissions from rice residue burning in western India and eastern Pakistan could impact particulate air pollution in Lumbini and surrounding regions in southern Nepal. Therefore, our finding is meaningful and has a great importance for adopting the appropriate mitigation measures, not only at the local level but also by involving different regions and nations, to reduce the biomass burning emissions in the broader IGP region nations.

scholarly journals Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: influence of biomass burning

2017 ◽  
Vol 17 (14) ◽  
pp. 8867-8885 ◽  
Author(s):  
Xin Wan ◽  
Shichang Kang ◽  
Quanlian Li ◽  
Dipesh Rupakheti ◽  
Qianggong Zhang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Vanillic Acid ◽  
Monsoon Season ◽  
Rural Site ◽  
Aerosol Composition ◽  
Gangetic Plain ◽  
Minimum Concentration ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
Indo Gangetic Plain

Abstract. To better understand the characteristics of biomass burning in the northern Indo-Gangetic Plain (IGP), total suspended particles were collected in a rural site, Lumbini, Nepal, during April 2013 to March 2014 and analyzed for the biomass burning tracers (i.e., levoglucosan, mannosan, vanillic acid). The annual average concentration of levoglucosan was 734 ± 1043 ng m−3 with the maximum seasonal mean concentration during post-monsoon season (2206 ± 1753 ng m−3), followed by winter (1161 ± 1347 ng m−3), pre-monsoon (771 ± 524 ng m−3) and minimum concentration during monsoon season (212 ± 279 ng m−3). The other biomass burning tracers (mannosan, galactosan, p-hydroxybenzoic acid, vanillic acid, syringic acid and dehydroabietic acid) also showed the similar seasonal variations. There were good correlations among levoglucosan, organic carbon (OC) and elemental carbon (EC), indicating significant impact of biomass burning activities on carbonaceous aerosol loading throughout the year in Lumbini area. According to the characteristic ratios, levoglucosan ∕ mannosan (lev ∕ man) and syringic acid ∕ vanillic acid (syr ∕ van), we deduced that the high abundances of biomass burning products during non-monsoon seasons were mainly caused by the burning of crop residues and hardwood while the softwood had less contribution. Based on the diagnostic tracer ratio (i.e., lev ∕ OC), the OC derived from biomass burning constituted large fraction of total OC, especially during post-monsoon season. By analyzing the MODIS fire spot product and 5-day air-mass back trajectories, we further demonstrated that organic aerosol composition was not only related to the local agricultural activities and residential biomass usage but also impacted by the regional emissions. During the post-monsoon season, the emissions from rice residue burning in western India and eastern Pakistan could impact particulate air pollution in Lumbini and surrounding regions in southern Nepal. Therefore, our finding is meaningful and has a great importance for adopting the appropriate mitigation measures, not only at the local level but also by involving different regions and nations, to reduce the biomass burning emissions in the broader IGP region nations.

scholarly journals Seasonal distribution and drivers of surface fine particulate matter and organic aerosol over the Indo-Gangetic Plain

2021 ◽  
Vol 21 (14) ◽  
pp. 10881-10909
Author(s):  
Caterina Mogno ◽  
Paul I. Palmer ◽  
Christoph Knote ◽  
Fei Yao ◽  
Timothy J. Wallington
Keyword(s):  
Particulate Matter ◽  
Monsoon Season ◽  
Fine Particulate Matter ◽  
Organic Aerosol ◽  
Substantial Contribution ◽  
Agricultural Crop ◽  
Gangetic Plain ◽  
Post Monsoon ◽  
Fine Particulate ◽  
Indo Gangetic Plain

Abstract. The Indo-Gangetic Plain (IGP) is home to 9 % of the global population and is responsible for a large fraction of agricultural crop production in Pakistan, India, and Bangladesh. Levels of fine particulate matter (mean diameter <2.5 µm, PM2.5) across the IGP often exceed human health recommendations, making cities across the IGP among the most polluted in the world. Seasonal changes in the physical environment over the IGP are dominated by the large-scale south Asian monsoon system that dictates the timing of agricultural planting and harvesting. We use the WRF-Chem model to study the seasonal anthropogenic, pyrogenic, and biogenic influences on fine particulate matter and its constituent organic aerosol (OA) over the IGP that straddles Pakistan, India, and Bangladesh during 2017–2018. We find that surface air quality during pre-monsoon (March–May) and monsoon (June–September) seasons is better than during post-monsoon (October–December) and winter (January–February) seasons, but all seasonal mean values of PM2.5 still exceed the recommended levels, so that air pollution is a year-round problem. Anthropogenic emissions influence the magnitude and distribution of PM2.5 and OA throughout the year, especially over urban sites, while pyrogenic emissions result in localised contributions over the central and upper parts of IGP in all non-monsoonal seasons, with the highest impact during post-monsoon seasons that correspond to the post-harvest season in the agricultural calendar. Biogenic emissions play an important role in the magnitude and distribution of PM2.5 and OA during the monsoon season, and they show a substantial contribution to secondary OA (SOA), particularly over the lower IGP. We find that the OA contribution to PM2.5 is significant in all four seasons (17 %–30 %), with primary OA generally representing the larger fractional contribution. We find that the volatility distribution of SOA is driven mainly by the mean total OA loading and the washout of aerosols and gas-phase aerosol precursors that result in SOA being less volatile during the pre-monsoon and monsoon season than during the post-monsoon and winter seasons.

scholarly journals High aerosol loading over mega city Delhi in the western Indo-Gangetic plain : Optical characteristics

MAUSAM ◽  
2021 ◽  
Vol 67 (3) ◽  
pp. 609-618
Author(s):  
S. D. ATTRI ◽  
V. K. SONI ◽  
S. TIWARI ◽  
A. K. SRIVASTAVA ◽  
SHANI TIWARI ◽  
...  
Keyword(s):  
North India ◽  
Winter Period ◽  
Gangetic Plain ◽  
Large Variability ◽  
Angstrom Exponent ◽  
Aerosol Loading ◽  
Post Monsoon ◽  
Ångström Exponent ◽  
Indo Gangetic Plain ◽  
Ångstrom Exponent

Measurements of aerosol optical properties were carried out at an urban mega city Delhi, which is situated in the western Indo-Gangetic Plain (IGP) region in north India using an automatic sun/sky radiometer during 2006-2008. The present study revealed high aerosol loading over the station, which could be due to its topography surrounded by different natural and anthropogenic emission sources, and may have major implications towards health, air quality and climate system. Results show a large variability in AOD during the study period, with nearly equal values during winter (0.67 ± 0.06) and summer (0.71 ± 0.11). The Ångström exponent (AE) values were found to be relatively higher during winter (1.19 ± 0.07, suggests dominance of fine-mode aerosols) and lower during summer (0.74±0.06, suggests dominance of coarse-mode aerosols). A slight decrease in single scattering albedo (SSA) was observed during the study period, with a mean value of ~0.9. SSA was found to be about 0.93 during post-monsoon and 0.96 during the winter period whereas during summer and monsoon, SSA was about 0.95. The estimated monthly absorption Ångström exponent (AAE) values over the station varied from 0.11 to 1.87, which were found to be less than 1.0 by ~55% time (mostly during winter and monsoon), and greater than 1.0 by ~45% time (mostly during summer and post-monsoon).

Radiative forcing of atmospheric brown clouds over the Indo-Gangetic Plain

2021 ◽  
Author(s):  
Manish Jangid ◽  
Amit Mishra
Keyword(s):  
Optical Depth ◽  
Radiative Forcing ◽  
Water Cycle ◽  
Monsoon Season ◽  
Regional Climate ◽  
Winter Season ◽  
Gangetic Plain ◽  
Post Monsoon ◽  
Using Data ◽  
Indo Gangetic Plain

&lt;p&gt;Atmospheric brown clouds (ABCs) are a dense and extensive pollution layer and have significant implications on air quality, agriculture, water cycle, and regional climate. The objective of the present study is to observe seasonal and spatial variations in the occurrence of ABCs and its radiative effects. The Indo-Gangetic plain (IGP) is the most populated region of India, which is an extended region in the foothills of the Himalayas. The IGP is one of the ABCs hotspots over the globe. The frequency of ABCs occurrences and radiative forcing were calculated using data from seven ground-based remote sensors situated across the IGP. We have used total ~ 5000 days of Level-2 aerosol measurements from seven AERosol Robotic NETwork (AERONET) stations (Karachi, Lahore, Jaipur, New Delhi, Kanpur, Gandhi college and Dhaka University) for three seasons (Pre-monsoon, Post-monsoon, and Winter) during 2000-2019. An algorithm based on the optical properties of aerosols is used to defined extreme pollution events (ABCs days) for each site. Our results show more frequent occurrences of ABCs over the region in the pre-monsoon out of all three seasons. However, spatial variation is found in all seasons, like maximum frequency of ABCs over western IGP region in post-monsoon and minimum is at eastern IGP region in the winter season. Further, we have used the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model to calculate radiative forcing during ABCs days on all sites of study. Aerosol optical depth (AOD) and absorption optical depth (AAOD) was used to calculate radiative forcing over the IGP region. Radiative forcing of ABCs is negative at both the surface (SRF) and top of the atmosphere (TOA), whereas it is positive in the atmosphere (ATM). In magnitude, it was found minimum in the pre-monsoon season at TOA. However, other seasons have specific features over specific locations, for example, in the winter season, radiative forcing is maximum over Kolkata at TOA, SRF, and ATM, which are -13.81 W/m&lt;sup&gt;2&lt;/sup&gt;, -50.90 W/m&lt;sup&gt;2&lt;/sup&gt;, and +37.09 W/m&lt;sup&gt;2&lt;/sup&gt; respectively. In the pre-monsoon season, radiative forcing is maximum at Delhi (-9.59 W/m&lt;sup&gt;2&lt;/sup&gt;) at TOA. In post-monsoon season radiative forcing maximum at Gandhi-college (-11.30 W/m&lt;sup&gt;2&lt;/sup&gt;) at TOA. This ground observation is also compared with Modern Era Retrospective analysis and Research and Applications-2 (MEERA 2) modal data. These results indicate the cooling effect of ABCs at the surface and TOA over the IGP region throughout the period.&lt;/p&gt;

Impact of Global Warming on Wetlands: A Case Study of Lucknow District

2017 ◽  
Vol 9 (01) ◽  
pp. 25-29
Author(s):  
Kashif Imdad ◽  
Agha Mansoor Khan
Keyword(s):  
Global Warming ◽  
Critical Role ◽  
Climatic Data ◽  
Agricultural Activities ◽  
Exponential Rate ◽  
Gangetic Plain ◽  
Imminent Threat ◽  
Indo Gangetic Plain ◽  
Topographical Maps

Wetlands are one of most productive environments and provide a wide variety of benefits. They are important repositories of biodiversity and play a critical role in the health, livelihood and economic prospects for the nearby rural population. Wetlands are under imminent threat by nature in form of global warming and by civilization in form of encroachments and reclamation of wetlands for farming and settlement. Along Indo-Gangetic plain wetlands have receded more than half of its size in last 50 years. Present paper attempts to analyse impact of climate change on wetlands of Lucknow. Methodology included analysis of temporal mapping of wetlands using Survey of India topographical maps (SOI) and satellite data, climatic data of area and ground verification for encroachment impacts. Results indicate that wetland of Lucknow are receding with exponential rate attributing to Global Warming, encroachment by human for settlement and agricultural activities.

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