Dry deposition fluxes of NH4+-N and NO3--N at a rural site of Indo-Gangetic Plain, India.

2021 ◽  
Author(s):  
Moh Naseem ◽  
Umesh Kulshrestha
Keyword(s):  
Size Distribution ◽  
Dry Deposition ◽  
Major Ions ◽  
Dominant Mode ◽  
Dust Particles ◽  
Rural Site ◽  
Gangetic Plain ◽  
Strong Base ◽  
Deposition Fluxes ◽  
Indo Gangetic Plain

<p>The world’s acute reactive nitrogen (Nr) deposition is chronically eroding the biospheric integrity and undermining earth system’s resilience to be in an accommodatable state. The present study comprehensively attempts to decipher the dry depositions of atmospheric inorganic Nr along with other major ions through dustfall fluxes. Authentic atmospheric dust samples were collected by incorporating a surrogate-surface approach at an agriculturally intensive rural site in Indo-Gangetic plain of India over a year-long temporal scale from October 2017-September 2018. The mean (±Standard Error) dry deposition fluxes of NH<sub>4</sub><sup>+</sup>-N and NO<sub>3</sub><sup>-</sup>-N during the whole study period were observed as 0.41±0.09 kg ha<sup>-1</sup> yr<sup>-1 </sup>and 6.51±1.58 kg ha<sup>-1</sup> yr<sup>-1</sup>, respectively. The total percent ionic contribution to the dustfall flux was observed 2.95% and the descending order of their percent contribution in total ionic fluxes were observed as SO<sub>4</sub><sup>2- </sup>(31.46%) > Cl<sup>-</sup> (15.74%) > K<sup>+</sup> (15.04%) > Ca<sup>2+</sup> (13.97%) > Na<sup>+</sup> (10.23 %) > NO<sub>3</sub><sup>-</sup> (7.06%) > Mg<sup>2+</sup> (4.43%) > F<sup>-</sup>(1.62%) > NH<sub>4</sub><sup>+</sup> (0.44%). The relative dominance of NO<sub>3</sub><sup>-</sup>-N over NH<sub>4</sub><sup>+</sup>-N fluxes was maintained in all seasons during the whole monitoring period which could be attributed to the competitive exclusion of NH<sub>4</sub><sup>+</sup>-N from acid-base neutralization reactions by other strong base cations in dustfall. Size-distribution and morphological analysis of dust particles from Scanning Electron Microscope images signified the anthropogenic involvement in shaping the dominant mode of particle-size distribution in dust fall fluxes which culminated into the dominance of fine-mode fraction over course-mode in dustfall.</p>

scholarly journals Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

2013 ◽  
Vol 13 (8) ◽  
pp. 21801-21835
Author(s):  
K. Osada ◽  
S. Ura ◽  
M. Kagawa ◽  
M. Mikami ◽  
T. Y. Tanaka ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Mineral Dust ◽  
Temporal Variations ◽  
Dust Particles ◽  
Insoluble Residue ◽  
Spatial Distributions ◽  
Dust Deposition ◽  
Deposition Fluxes ◽  
Deposition Amount

Abstract. Data of temporal variations and spatial distributions of mineral dust deposition fluxes are very limited in terms of duration, location, and processes of deposition. To ascertain temporal variations and spatial distributions of mineral dust deposition by wet and dry processes, weekly deposition samples were obtained at Sapporo, Toyama, Nagoya, Tottori, Fukuoka, and Cape Hedo (Okinawa) in Japan during October 2008–December 2010 using automatic wet and dry separating samplers. Mineral dust weights in water-insoluble residue were estimated from Fe contents measured using an X-ray fluorescence analyzer. For wet deposition, highest and lowest annual dust fluxes were found at Toyama (9.6 g m−2 yr−1) and at Cape Hedo (1.7 g m−2 yr−1) as average values in 2009 and 2010. Higher wet deposition fluxes were observed at Toyama and Tottori, where frequent precipitation (>60% days per month) was observed during dusty seasons. For dry deposition among Toyama, Tottori, Fukuoka, and Cape Hedo, the highest and lowest annual dust fluxes were found respectively at Fukuoka (5.2 g m−2 yr−1) and at Cape Hedo (2.0 g m−2 yr−1) as average values in 2009 and 2010. Although the seasonal tendency of the monthly dry deposition amount roughly resembled that of monthly days of Kosa dust events, the monthly amount of dry deposition was not proportional to monthly days of the events. Comparison of dry deposition fluxes with vertical distribution of dust particles deduced from Lidar data and coarse particle concentrations suggested that the maximum dust layer height or thickness is an important factor for controlling the dry deposition amount after long-range transport of dust particles. Size distributions of refractory dust particles were obtained using four-stage filtration: >20, >10, >5, and >1 μm diameter. Weight fractions of the sum of >20 μm and 10–20 μm (giant fraction) were higher than 50% for most of the event samples. Irrespective of the deposition type, the giant dust fractions were decreasing generally with increasing distance from the source area, suggesting the selective depletion of larger giant particles during atmospheric transport. Because giant dust particles are an important mass fraction of dust accumulation, especially in the north Pacific where is known as a high-nutrient, low-chlorophyll (HNLC) region, the transport height of giant dust particles is an important factor for studying dust budgets in the atmosphere and their role in biogeochemical cycles.

scholarly journals Wet Deposition of Total Dissolved Nitrogen in Indo-Gangetic Plain (India)

2021 ◽  
Author(s):  
Manisha Mishra ◽  
Umesh Chandra Kulshrestha
Keyword(s):  
Wet Deposition ◽  
Animal Husbandry ◽  
Rural Site ◽  
Urban Site ◽  
Organic N ◽  
Major Influence ◽  
Limited Information ◽  
Monsoon Period ◽  
Gangetic Plain ◽  
Indo Gangetic Plain

Abstract Very limited information on the magnitude and environmental impacts of both inorganic as well as organic forms of Nitrogen (N) wet deposition is available in India. Molar concentrations of inorganic (NH4+ and NO3−) and organic N in rainwater were monitored at three different land-use sites in Indo-Gangetic Plain (IGP) during the monsoon period (June-September) of 2017. It has been observed that dissolved organic N (DON) contributed significantly to the total dissolved N (TDN) ranging from 5–60%. Dissolved inorganic N (DIN = NH4+ + NO3−) concentration was recorded as high as 221.0 µmol L− 1 at urban site to as low as 65.9 µmol L− 1 at the rural site. A similar pattern was also observed for DON. NH4+ contribution to TDN had the order: urban megacity (65%) > urban (70%) > rural (75%). Agriculture and animal husbandry are the primary sources of NH4+ emissions in the rural site. However, NO3− has shown a contrasting trend at these sites (25%, 15% and 8%, respectively). Wet deposition fluxes of atmospheric TDN was observed to be higher at urban sites. This can attributed to a variety of local sources such as vehicular emission, microbial emissions, biomass burning, human excreta due to higher population density, and transportation from surrounding areas, as observed from concentration weighted trajectories (CWT) model and cluster analysis. Upwind region of IGP has experienced major influence of air mass transported from agriculturally rich northwest part of India. However, both the downwind sites have experienced by-and-large the influence of south-westerly air-masses originated over the Arabian Sea. Study has found that the DON contributes significantly to TDN and need to be included for budget assessment in South Asia.

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 Study of MODIS derived AOD at three different locations in the Indo Gangetic Plain: Kanpur, Gandhi College and Nainital

2012 ◽  
Vol 30 (10) ◽  
pp. 1479-1493 ◽  
Author(s):  
P. Choudhry ◽  
A. Misra ◽  
S. N. Tripathi
Keyword(s):  
Indian Subcontinent ◽  
Rural Site ◽  
Urban Site ◽  
Gangetic Plain ◽  
Large Variability ◽  
Entire Area ◽  
Aerosol Model ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
A Site ◽  
Indo Gangetic Plain

Abstract. Moderate resolution imaging spectroradiometer (MODIS) sensors, onboard Terra and Aqua, have been observing the Earth since start of 2000 and mid 2002, respectively. The present study provides a comparison of Collection 5 (C005), aerosol optical depth (AOD) retrieved by MODIS, with AERONET-observed AOD over Kanpur (an urban site), Gandhi College (a rural site) and Nainital (a relatively clean site) in the Indo Gangetic Plain (IGP). The results show that at Kanpur, MODIS retrievals are well within the prelaunch uncertainty ± 0.05 ±0.15 τ, and a good correlation (R2 > 0.7 for both Terra and Aqua). Nainital also shows good retrieval (R2 > 0.8 for Terra and R2 > 0.68 for Aqua), as more than 66% of total collocations are within the prelaunch uncertainty. However, it is seen that there is significant overestimation in this case, especially in the months of winter. Gandhi College poses a challenge to MODIS retrieval, as here <57% of MODIS-retrieved AOD values lay within the prelaunch uncertainty and the correlation is very poor (R2 ~ 0.5 for Aqua and R2 ~ 0.4 for Terra); also there is persistent underestimation in this case. Small value of slope shows that assumed model results in underestimation, and large intercept values for the linear regression fit show that errors due to surface reflectance are high here. Our comparison shows that MODIS retrieval works well over Kanpur, and Nainital with winter as an exception. However, MODIS retrieval is poor for Gandhi College which is a rural area. The aerosol properties at Kanpur are currently used as representative of the entire subcontinent in the MODIS C005 algorithm, which is not an accurate assumption. The large variability in land use and climate over India makes it a site too complex for a single aerosol model to be used over the entire area. Therefore further study with as many sites as possible over the Indian subcontinent would help provide more realistic modeling for the Indian subcontinent.

scholarly journals Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

2014 ◽  
Vol 14 (2) ◽  
pp. 1107-1121 ◽  
Author(s):  
K. Osada ◽  
S. Ura ◽  
M. Kagawa ◽  
M. Mikami ◽  
T. Y. Tanaka ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Mineral Dust ◽  
Potential Temperature ◽  
Temporal Variations ◽  
Dust Particles ◽  
Spatial Distributions ◽  
Dust Deposition ◽  
Deposition Fluxes ◽  
Wet And Dry Deposition

Abstract. Recent ground networks and satellite remote-sensing observations have provided useful data related to spatial and vertical distributions of mineral dust particles in the atmosphere. However, measurements of temporal variations and spatial distributions of mineral dust deposition fluxes are limited in terms of their duration, location, and processes of deposition. To ascertain temporal variations and spatial distributions of mineral dust deposition using wet and dry processes, weekly deposition samples were obtained at Sapporo, Toyama, Nagoya, Tottori, Fukuoka, and Cape Hedo (Okinawa) in Japan during October 2008–December 2010 using automatic wet and dry separating samplers. Mineral dust weights in water-insoluble residue were estimated from Fe contents measured using an X-ray fluorescence analyser. Wet and dry deposition fluxes of mineral dusts were both high in spring and low in summer, showing similar seasonal variations to frequency of aeolian dust events (Kosa) in Japan. For wet deposition, highest and lowest annual dust fluxes were found at Toyama (9.6 g m−2 yr−1) and at Cape Hedo (1.7 g m−2 yr−1) as average values in 2009 and 2010. Higher wet deposition fluxes were observed at Toyama and Tottori, where frequent precipitation (> 60% days per month) was observed during dusty seasons. For dry deposition among Toyama, Tottori, Fukuoka, and Cape Hedo, the highest and lowest annual dust fluxes were found respectively at Fukuoka (5.2 g m−2 yr−1) and at Cape Hedo (2.0 g m−2 yr−1) as average values in 2009 and 2010. The average ratio of wet and dry deposition fluxes was the highest at Toyama (3.3) and the lowest at Hedo (0.82), showing a larger contribution of the dry process at western sites, probably because of the distance from desert source regions and because of the effectiveness of the wet process in the dusty season. Size distributions of refractory dust particles were obtained using four-stage filtration: > 20, > 10, > 5, and > 1 μm diameter. Weight fractions of the sum of > 20 μm and 10–20 μm (giant fraction) were higher than 50% for most of the event samples. Irrespective of the deposition type, the giant dust fractions generally decreased with increasing distance from the source area, suggesting the selective depletion of larger giant particles during atmospheric transport. Based on temporal variations of PMc (2.5 < D < 10 μm), ground-based lidar, backward air trajectories, and vertical profiles of potential temperatures, transport processes of dust particles are discussed for events with high-deposition and low-deposition flux with high PMc. Low dry dust depositions with high PMc concentrations were observed under stronger (5 K km−1) stratification of potential temperature with thinner and lower (< 2 km) dust distributions because the PMc fraction of dust particles only survived after depletion of giant dust particles by rapid gravitational settling at the time they reach Japan. In contrast, transport through a thicker (> 2 km) dust layer with weak vertical gradient of potential temperature carry more giant dust particles to Japan. Because giant dust particles are an important mass fraction of dust accumulation, especially in the North Pacific, which is known as a high-nutrient, low-chlorophyll (HNLC) region, the transport height and fraction of giant dust particles are important factors for studying dust budgets in the atmosphere and their role in biogeochemical cycles.

Sign in / Sign up

Export Citation Format

Share Document