Atmospheric abundance of HULIS during wintertime in Indo-Gangetic Plain: impact of biomass burning emissions

2018 ◽  
Vol 75 (4) ◽  
pp. 385-398 ◽  
Author(s):  
Varun Kumar ◽  
Prashant Rajput ◽  
Anubha Goel
2021 ◽  
Vol 21 (21) ◽  
pp. 16427-16452
Author(s):  
Shohei Nomura ◽  
Manish Naja ◽  
M. Kawser Ahmed ◽  
Hitoshi Mukai ◽  
Yukio Terao ◽  
...  

Abstract. Emissions of greenhouse gases (GHGs) from the Indian subcontinent have increased during the last 20 years along with rapid economic growth; however, there remains a paucity of GHG measurements for policy-relevant research. In northern India and Bangladesh, agricultural activities are considered to play an important role in GHG concentrations in the atmosphere. We performed weekly air sampling at Nainital (NTL) in northern India and Comilla (CLA) in Bangladesh from 2006 and 2012, respectively. Air samples were analyzed for dry-air gas mole fractions of CO2, CH4, CO, H2, N2O, and SF6 and carbon and oxygen isotopic ratios of CO2 (δ13C-CO2 and δ18O-CO2). Regional characteristics of these components over the Indo-Gangetic Plain are discussed compared to data from other Indian sites and Mauna Loa, Hawaii (MLO), which is representative of marine background air. We found that the CO2 mole fraction at CLA had two seasonal minima in February–March and September, corresponding to crop cultivation activities that depend on regional climatic conditions. Although NTL had only one clear minimum in September, the carbon isotopic signature suggested that photosynthetic CO2 absorption by crops cultivated in each season contributes differently to lower CO2 mole fractions at both sites. The CH4 mole fraction of NTL and CLA in August–October showed high values (i.e., sometimes over 4000 ppb at CLA), mainly due to the influence of CH4 emissions from the paddy fields. High CH4 mole fractions sustained over months at CLA were a characteristic feature on the Indo-Gangetic Plain, which were affected by both the local emission and air mass transport. The CO mole fractions at NTL were also high and showed peaks in May and October, while CLA had much higher peaks in October–March due to the influence of human activities such as emissions from biomass burning and brick production. The N2O mole fractions at NTL and CLA increased in June–August and November–February, which coincided with the application of nitrogen fertilizer and the burning of biomass such as the harvest residues and dung for domestic cooking. Based on H2 seasonal variation at both sites, it appeared that the emissions in this region were related to biomass burning in addition to production from the reaction of OH and CH4. The SF6 mole fraction was similar to that at MLO, suggesting that there were few anthropogenic SF6 emission sources in the district. The variability of the CO2 growth rate at NTL was different from the variability in the CO2 growth rate at MLO, which is more closely linked to the El Niño–Southern Oscillation (ENSO). In addition, the growth rates of the CH4 and SF6 mole fractions at NTL showed an anticorrelation with those at MLO, indicating that the frequency of southerly air masses strongly influenced these mole fractions. These findings showed that rather large regional climatic conditions considerably controlled interannual variations in GHGs, δ13C-CO2, and δ18O-CO2 through changes in precipitation and air mass.


2019 ◽  
Vol 19 (1) ◽  
pp. 163-180 ◽  
Author(s):  
Abhinandan Ghosh ◽  
Arindam Roy ◽  
Abhijit Chatterjee ◽  
Sanat K. Das ◽  
Sanjay K. Ghosh ◽  
...  

2017 ◽  
Author(s):  
Xin Wan ◽  
Shichang Kang ◽  
Quanlian Li ◽  
Dipesh Rupakheti ◽  
Qianggong Zhang ◽  
...  

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.


2017 ◽  
Vol 17 (14) ◽  
pp. 8867-8885 ◽  
Author(s):  
Xin Wan ◽  
Shichang Kang ◽  
Quanlian Li ◽  
Dipesh Rupakheti ◽  
Qianggong Zhang ◽  
...  

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.


2018 ◽  
Author(s):  
Nandita Singh ◽  
Tirthankar Banerjee ◽  
Made P. Raju ◽  
Karine Deboudt ◽  
Meytar Sorek-Hamer ◽  
...  

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.


2014 ◽  
Vol 14 (12) ◽  
pp. 5921-5941 ◽  
Author(s):  
V. Sinha ◽  
V. Kumar ◽  
C. Sarkar

Abstract. One seventh of the world's population lives in the Indo-Gangetic Plain (IGP) and the fertile region sustains agricultural food crop production for much of South Asia, yet it remains one of the most under-studied regions of the world in terms of atmospheric composition and chemistry. In particular, the emissions and chemistry of volatile organic compounds (VOCs) that form surface ozone and secondary organic aerosol through photochemical reactions involving nitrogen oxides are not well understood. In this study, ambient levels of VOCs such as methanol, acetone, acetaldehyde, acetonitrile and isoprene were measured for the first time in the IGP. A new atmospheric chemistry facility that combines India's first high-sensitivity proton transfer reaction mass spectrometer, an ambient air quality station and a meteorological station, was used to quantify in situ levels of several VOCs and air pollutants in May 2012 at a suburban site in Mohali (northwest IGP). Westerly winds arriving at high wind speeds (5–20 m s−1) in the pre-monsoon season at the site were conducive for chemical characterization of regional emission signatures. Average levels of VOCs and air pollutants in May~2012 ranged from 1.2 to 2.7 nmol mol−1 for aromatic VOCs, 5.9 to 37.5 nmol mol−1 for the oxygenated VOCs, 1.4 nmol mol−1 for acetonitrile, 1.9 nmol mol−1 for isoprene, 567 nmol mol−1 for carbon monoxide, 57.8 nmol mol−1 for ozone, 11.5 nmol mol−1 for nitrogen oxides, 7.3 nmol mol−1 for sulfur dioxide, 104 μg m−3 for PM2.5 and 276 μg m−3 for PM10. By analyzing the one-minute in situ data with meteorological parameters and applying chemical tracers (e.g., acetonitrile for biomass burning) and inter-VOC correlations, we were able to constrain major emission source activities on both temporal and diel scales. Wheat residue burning caused massive increases (> 3 times the baseline values) for all the measured VOCs and primary pollutants. Other forms of biomass burning at night were also a significant source of oxygenated VOCs and isoprene (r2 with acetonitrile ≥0.5 for nighttime data), which is remarkable in terms of atmospheric chemistry implications. Surface ozone exceeded the 8 h national ambient air quality limit of 100 μg O3 m−3 (~50 ppbv) on a daily basis, except for 17 May 2012, when a severe dust storm event (PM2.5 > 800 μg m−3; PM10 > 2700 μg m−3) characterized by long-range transport from the west impacted the site. The novel data set and results point to the occurrence of high primary emissions of reactive VOCs. They also highlight the urgent need for establishing more comprehensive observational facilities in the IGP to constrain the spatial and seasonal variability of atmospheric chemical constituents. Such efforts will enable a mechanistic-level understanding of the in situ chemical processes controlling the formation of surface ozone, a necessary step for effective ozone mitigation and improvement of the regional air quality.


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