scholarly journals Comparison of emission profile of black carbon and carbon monoxide over Eastern India: source apportionment and health risk impact

2021 ◽  
Author(s):  
Balram Ambade ◽  
Tapan Kumar Sankar ◽  
Lokesh K. Sahu ◽  
Sneha Gautam ◽  
Alok Sagar Gautam
Keyword(s):  
Carbon Monoxide ◽  
Health Risk ◽  
Black Carbon ◽  
Strong Positive Correlation ◽  
Eastern India ◽  
Gangetic Plain ◽  
Positive Correlation ◽  
Eastern State ◽  
School Aged Children ◽  
Indo Gangetic Plain

Abstract In the present study, black carbon (BC) mass concentration and carbon monoxide (CO) combination ratio were calculated simultaneously at two different cities (i.e.,Jamshedpur (JSR) and Kharagpur (KGP)) located in the eastern state of India. The analysis of GIOVANI NASA data indicates the highest concentrations of BC and CO in the Indo-Gangetic Plain (IGP) as well as the eastern part of India. The BC-CO relationship exhibited an excellent positive correlation (r2 = 0.65), while BC-PM2.5 showed a strong positive correlation (r2 > 0.96). On the other hand, the backward air trajectory showed pollutant transport mainly from India's northern part with some contributions from other countries likePakistan, Nepal, Bhutan etc. BC concentration overall health risk assessment was demonstrated as 6.27, 12.43, 11.22 and 25.60 in JSR and 2.02, 4.02, 3.63 and 8.28 in KGP, passive cigarettes comparable concerning the risk of lung cancer, low birth weight, cardiovascular mortality, and percentage lung function decrement of school-aged children.

scholarly journals Characterization of Black Carbon and Its Correlations with VOCs in the Northern Region of Hangzhou Bay in Shanghai, China

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 870
Author(s):  
Fangfang Wang ◽  
Jialuo Xu ◽  
Yinzhi Huang ◽  
Guangli Xiu
Keyword(s):  
Global Warming ◽  
Black Carbon ◽  
Northern Region ◽  
Hangzhou Bay ◽  
Industrial Park ◽  
Strong Positive Correlation ◽  
Incomplete Combustion ◽  
Positive Correlation ◽  
Industrial Parks ◽  
Haze Pollution

Ozone and PM2.5 (all particulate matter with diameter of 2.5 µm or smaller) are currently two disturbing environmental issues in most cities of China. Black carbon (BC), mainly from incomplete combustion, is one of the most important components of PM2.5 because it can absorb light and contribute to haze pollution and global warming. Meanwhile, volatile organic compounds (VOCs) have become a major air pollutant due to their association with haze, ozone (O3), global warming and human health by direct or indirect processes. In this study, one year-long observation campaign of BC, VOCs and other conventional air pollutants was conducted in the Northern Region of the Hangzhou Bay (NRHB) in Shanghai, China. The results indicated that higher concentration of BC mainly occurred in the autumn and winter, especially in December. In December, higher BC concentrations were found when the air mass came from northwest where there is an important local freeway, or southwest where some adjacent southwest chemical industrial parks are located. Different from the characteristics of BC in urban areas reported by previous studies, the diurnal variation of BC exhibited three peaks, two of which coincided with the morning and evening rush hours which are related to the heavy diesel traffic from a nearby freeway, and the third peak was often found late at night, around 2 am, which might be associated with abnormal emissions from an industrial park or marine traffic in the ocean waterway. BC had weakly negative correlation with O3 and NO, and a strongly positive correlation with PM2.5, SO2, NO2 and NOx, which implies that some incomplete combustion sources might occur in the nearby regions. With regard to VOCs, BC had a strong positive correlation with alkane, alkenes, alkynes, aromatic and non-sulfur VOCs, particularly with aromatic organic matter. Unlike the stronger correlation with aromatics in the morning rush hours, a stronger correlation between BC and alkenes and alkynes during the evening rush hour was observed. The relationships between BC and VOCs, particularly with some specific VOCs species related to the neighboring chemical industrial park, demonstrated that the contribution of the surrounding chemical industrial parks to BC should not be neglected.

scholarly journals Wintertime direct radiative effects due to black carbon (BC) over the Indo-Gangetic Plain as modelled with new BC emission inventories in CHIMERE

2021 ◽  
Vol 21 (10) ◽  
pp. 7671-7694
Author(s):  
Sanhita Ghosh ◽  
Shubha Verma ◽  
Jayanarayanan Kuttippurath ◽  
Laurent Menut
Keyword(s):  
Black Carbon ◽  
Transport Model ◽  
Eastern Coast ◽  
Emission Inventories ◽  
Surface Cooling ◽  
Gangetic Plain ◽  
Bottom Up ◽  
Bc Aerosols ◽  
Radiative Perturbation ◽  
Indo Gangetic Plain

Abstract. To reduce the uncertainty in climatic impacts induced by black carbon (BC) from global and regional aerosol–climate model simulations, it is a foremost requirement to improve the prediction of modelled BC distribution, specifically over the regions where the atmosphere is loaded with a large amount of BC, e.g. the Indo-Gangetic Plain (IGP) in the Indian subcontinent. Here we examine the wintertime direct radiative perturbation due to BC with an efficiently modelled BC distribution over the IGP in a high-resolution (0.1∘ × 0.1∘) chemical transport model, CHIMERE, implementing new BC emission inventories. The model efficiency in simulating the observed BC distribution was assessed by executing five simulations: Constrained and bottomup (bottomup includes Smog, Cmip, Edgar, and Pku). These simulations respectively implement the recently estimated India-based observationally constrained BC emissions (Constrainedemiss) and the latest bottom-up BC emissions (India-based: Smog-India; global: Coupled Model Intercomparison Project phase 6 – CMIP6, Emission Database for Global Atmospheric Research-V4 – EDGAR-V4, and Peking University BC Inventory – PKU). The mean BC emission flux from the five BC emission inventory databases was found to be considerably high (450–1000 kg km−2 yr−1) over most of the IGP, with this being the highest (> 2500 kg km−2 yr−1) over megacities (Kolkata and Delhi). A low estimated value of the normalised mean bias (NMB) and root mean square error (RMSE) from the Constrained estimated BC concentration (NMB: < 17 %) and aerosol optical depth due to BC (BC-AOD) (NMB: 11 %) indicated that simulations with Constrainedemiss BC emissions in CHIMERE could simulate the distribution of BC pollution over the IGP more efficiently than with bottom-up emissions. The high BC pollution covering the IGP region comprised a wintertime all-day (daytime) mean BC concentration and BC-AOD respectively in the range 14–25 µg m−3 (6–8 µg m−3) and 0.04–0.08 µg m−3 from the Constrained simulation. The simulated BC concentration and BC-AOD were inferred to be primarily sensitive to the change in BC emission strength over most of the IGP (including the megacity of Kolkata), but also to the transport of BC aerosols over megacity Delhi. Five main hotspot locations were identified in and around Delhi (northern IGP), Prayagraj–Allahabad–Varanasi (central IGP), Patna–Palamu (upper, lower, and mideastern IGP), and Kolkata (eastern IGP). The wintertime direct radiative perturbation due to BC aerosols from the Constrained simulation estimated the atmospheric radiative warming (+30 to +50 W m−2) to be about 50 %–70 % larger than the surface cooling. A widespread enhancement in atmospheric radiative warming due to BC by 2–3 times and a reduction in surface cooling by 10 %–20 %, with net warming at the top of the atmosphere (TOA) of 10–15 W m−2, were noticed compared to the atmosphere without BC, for which a net cooling at the TOA was exhibited. These perturbations were the strongest around megacities (Kolkata and Delhi), extended to the eastern coast, and were inferred to be 30 %–50% lower from the bottomup than the Constrained simulation.

scholarly journals Black Carbon physical and optical properties across northern India during pre-monsoon and monsoon seasons

2019 ◽  
Author(s):  
James Brooks ◽  
Dantong Liu ◽  
James D. Allan ◽  
Paul I. Williams ◽  
Jim Haywood ◽  
...  
Keyword(s):  
Physical Properties ◽  
Black Carbon ◽  
Mixing State ◽  
Atmospheric Measurements ◽  
Core Diameter ◽  
Gangetic Plain ◽  
North West ◽  
North East ◽  
Northern India ◽  
Indo Gangetic Plain

Abstract. Black carbon (BC) is known to have major impacts on both climate and human health, so is therefore of global importance, particularly so in regions close to large populations that have strong sources. The physical properties and mixing state of black carbon containing particles are important determinants in these effects but information is often lacking, particularly in some of the most important regions of the globe. Detailed analysis into the vertical and horizontal BC optical and physical properties across northern India has been carried out using airborne in-situ measurements. The size-resolved mixing state of BC-containing particles was characterised using a single particle soot photometer (SP2). The study focusses on the Indo-Gangetic Plain during the pre-monsoon and monsoon seasons. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights during the pre-monsoon (11th and 12th June) and monsoon (30th June to 11th July) seasons of 2016. Over the Indo-Gangetic Plain, BC mass concentrations were greater (1.95 µg/m3) compared to north-west India (1.50 µg/m3) and north-east India (0.70 µg/m3) during the pre-monsoon. Across northern India, two distinct BC modes were recorded; a mode of small BC particles (core diameter 

Evaluation of emission strength efficacy in simulating black carbon burden with CHIMERE: estimating wintertime radiative effect over Indo-Gangetic Plain

2020 ◽  
Author(s):  
Sanhita Ghosh ◽  
Shubha Verma ◽  
Jayanarayanan Kuttippurath
Keyword(s):  
Black Carbon ◽  
Transport Model ◽  
Indian Subcontinent ◽  
Chemical Transport ◽  
Climate Impacts ◽  
Eastern Coast ◽  
Spatial And Temporal Patterns ◽  
Gangetic Plain ◽  
Bc Aerosols ◽  
Indo Gangetic Plain

&lt;p&gt;Black carbon (BC) aerosols over the Indian subcontinent have been represented inadequately so-far in chemical transport models restricting the accurate assessment of BC-induced climate impacts. The divergence between simulated and measured BC concentration has specifically been reported to be large over the Indo-Gangetic Plain (IGP) during winter when a large BC burden is observed. In this study, we evaluate the BC transport simulations over the IGP in a high resolution (0.1&amp;#186; &amp;#215; 0.1&amp;#186; ) chemical transport model, CHIMERE. We examine the model efficiency to simulate the observed BC distribution executing five sets of simulation experiments: &lt;em&gt;Constrained &lt;/em&gt;and&lt;em&gt; bottomup&lt;/em&gt; (&lt;em&gt;Smog, Pku, Edgar, Cmip&lt;/em&gt;) implementing respectively, the recently estimated India-based constrained BC emission and the latest bottom-up BC emissions (India-based: Smog-India, and global: Coupled Model Intercomparison Project phase 6 (CMIP6), Emission Database for Global Atmospheric Research-V4 (EDGAR-V4) and Peking University BC Inventory (PKU)). The mean BC emission flux over most of the IGP from the five emission datasets is considerably high (450&amp;#8211;1000 kg km&lt;sup&gt;-2&lt;/sup&gt; y&lt;sup&gt;-1&lt;/sup&gt;) with a relatively low divergence obtained for the eastern and upper-mideastern IGP. Evaluation of BC transport simulations shows that the spatial and temporal gradient in the simulated BC concentration from the &lt;em&gt;Constrained &lt;/em&gt;was equivalent to that from the &lt;em&gt;bottomup&lt;/em&gt; and also to that from observations. This indicates that the spatial and temporal patterns of BC concentration are consistently simulated by the model processes. However, the efficacy to simulate BC distribution is commendable for the estimates from &lt;em&gt;Constrained&lt;/em&gt; for which the lowest normalised mean bias (NMB, &lt; 20%) is obtained in comparison to that from the &lt;em&gt;bottomup&lt;/em&gt; (37&amp;#8211;52%). 75&amp;#8211;100% of the observed all-day (daytime) mean BC concentration is simulated most of the times (&gt;80% of the number of stations data) for &lt;em&gt;Constrained&lt;/em&gt;, whereas, this being less frequent (&lt;50%) for the &lt;em&gt;Pku, Smog, Edgar&lt;/em&gt; and poor for &lt;em&gt;Cmip&lt;/em&gt;. The BC-AOD (0.04&amp;#8211;0.08) estimated from the &lt;em&gt;Constrained&lt;/em&gt; is 20&amp;#8211;50% higher than the &lt;em&gt;Pku&lt;/em&gt; and &lt;em&gt;Smog&lt;/em&gt;. Three main hotspot locations comprising of a large value of BC load are identified over the eastern, mideastern, and northern IGP. Assessment of the effect of BC burden on the wintertime radiative perturbation over the IGP shows that the presence of BC aerosols in the atmosphere enhances atmospheric heating by 2&amp;#8211;3 times more compared to that considering atmosphere without BC. Also, a net warming at the top of the atmosphere (TOA) by 10&amp;#8211;17 W m&lt;sup&gt;-&lt;/sup&gt;&lt;sup&gt;2&lt;/sup&gt; is noticed from the &lt;em&gt;Constrained&lt;/em&gt;, with the largest value estimated in and around megacities (Kolkata and Delhi) that extends to the eastern coast. This value is higher by 10&amp;#8211;20% than that from &lt;em&gt;Cmip&lt;/em&gt; over the IGP and by 2&amp;#8211;10% than that from &lt;em&gt;Smog&lt;/em&gt; over Delhi and eastern part of the IGP.&lt;/p&gt;

scholarly journals Correlation of black carbon aerosol and carbon monoxide in the high-altitude environment of Mt. Huang in Eastern China

2011 ◽  
Vol 11 (18) ◽  
pp. 9735-9747 ◽  
Author(s):  
X. L. Pan ◽  
Y. Kanaya ◽  
Z. F. Wang ◽  
Y. Liu ◽  
P. Pochanart ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
High Altitude ◽  
Black Carbon ◽  
Mass Concentration ◽  
Eastern China ◽  
Chemical Compositions ◽  
Strong Positive Correlation ◽  
Mixing Ratio ◽  
Air Masses ◽  
The Impact

Abstract. Understanding the relationship between black carbon (BC) and carbon monoxide (CO) will help improve BC emission inventories and the evaluation of global/regional climate forcing effects. In the present work, the BC (PM1) mass concentration and CO mixing ratio were continuously measured at a high-altitude background station on the summit of Mt. Huang (30.16° N, 118.26° E, 1840 m a.s.l.). Annual mean BC mass concentration was 1004.5 ± 895.5 ng m−3 with maxima in spring and autumn, and annual mean CO mixing ratio was 424.1 ± 159.2 ppbv. A large increase of CO was observed in the cold season, implying the contribution from the large-scale domestic coal/biofuel combustion for heating. The BC-CO relationship was found to show different seasonal features but strong positive correlation (R>0.8). In Mt. Huang area, the ΔBC/ΔCO ratio showed unimodal diurnal variations and had a maximum during the day (09:00–17:00 LST) and minimum at night (21:00–04:00 LST) in all seasons, indicating the impact of planetary boundary layer and the intrusion of clean air masses from the high troposphere. Back trajectory cluster analysis showed that the ΔBC/ΔCO ratio of plumes from the Eastern China (Jiangsu, Zhejiang provinces and Shanghai) was 8.8 ± 0.9 ng m−3 ppbv−1. Transportation and industry were deemed as controlling factors of the BC-CO relationship in this region. The ΔBC/ΔCO ratios for air masses from Northern China (Anhui, Henan, Shanxi and Shandong provinces) and southern China (Jiangxi, Fujian and Hunan provinces) were quite similar with mean values of 6.5 ± 0.4 and 6.5 ± 0.2 ng m−3 ppbv−1 respectively. The case studies combined with satellite observations demonstrated that the ΔBC/ΔCO ratio for biomass burning (BB) plumes were 10.3 ± 0.3 and 11.6 ± 0.5ng m−3 ppbv−1, significantly higher than those during non-BB impacted periods. The loss of BC during transport was also investigated on the basis of the ΔBC/ΔCO-RH (relative humidity) relationship along air mass pathways. The results showed that BC particles from Eastern China area was much more easily removed from atmosphere than other inland regions due to the higher RH along transport pathway, implying the importance of chemical compositions and mixing states on BC residence time in the atmosphere.

scholarly journals A global 3-D CTM evaluation of black carbon in the Tibetan Plateau

2014 ◽  
Vol 14 (13) ◽  
pp. 7091-7112 ◽  
Author(s):  
C. He ◽  
Q. B. Li ◽  
K. N. Liou ◽  
J. Zhang ◽  
L. Qi ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Black Carbon ◽  
Transport Model ◽  
The Tibetan Plateau ◽  
Emission Inventories ◽  
Chemical Transport Model ◽  
Central Plateau ◽  
Gangetic Plain ◽  
Rural Sites ◽  
Indo Gangetic Plain

Abstract. We systematically evaluate the black carbon (BC) simulations for 2006 over the Tibetan Plateau by a global 3-D chemical transport model (CTM) (GEOS-Chem) driven by GEOS-5 assimilated meteorological fields, using in situ measurements of BC in surface air, BC in snow, and BC absorption aerosol optical depth (AAOD). Using improved anthropogenic BC emission inventories for Asia that account for rapid technology renewal and energy consumption growth (Zhang et al., 2009; Lu et al., 2011) and improved global biomass burning emission inventories that account for small fires (van der Werf et al., 2010; Randerson et al., 2012), we find that model results of both BC in surface air and in snow are statistically in good agreement with observations (biases < 15%) away from urban centers. Model results capture the seasonal variations of the surface BC concentrations at rural sites in the Indo-Gangetic Plain, but the observed elevated values in winter are absent. Modeled surface-BC concentrations are within a factor of 2 of the observations at remote sites. Part of the discrepancy is explained by the deficiencies of the meteorological fields over the complex Tibetan terrain. We find that BC concentrations in snow computed from modeled BC deposition and GEOS-5 precipitation are spatiotemporally consistent with observations (r = 0.85). The computed BC concentrations in snow are a factor of 2–4 higher than the observations at several Himalayan sites because of excessive BC deposition. The BC concentrations in snow are biased low by a factor of 2 in the central plateau, which we attribute to the absence of snow aging in the CTM and strong local emissions unaccounted for in the emission inventories. Modeled BC AAOD is more than a factor of 2 lower than observations at most sites, particularly to the northwest of the plateau and along the southern slopes of the Himalayas in winter and spring, which is attributable in large part to underestimated emissions and the assumption of external mixing of BC aerosols in the model. We find that assuming a 50% increase of BC absorption associated with internal mixing reduces the bias in modeled BC AAOD by 57% in the Indo-Gangetic Plain and the northeastern plateau and to the northeast of the plateau, and by 16% along the southern slopes of the Himalayas and to the northwest of the plateau. Both surface BC concentration and AAOD are strongly sensitive to anthropogenic emissions (from China and India), while BC concentration in snow is especially responsive to the treatment of BC aerosol aging. We find that a finer model resolution (0.5° × 0.667° nested over Asia) reduces the bias in modeled surface-BC concentration from 15 to 2%. The large range and non-homogeneity of discrepancies between model results and observations of BC across the Tibetan Plateau undoubtedly undermine current assessments of the climatic and hydrological impact of BC in the region and thus warrant imperative needs for more extensive measurements of BC, including its concentration in surface air and snow, AAOD, vertical profile and deposition.

Limitation of the Use of the Absorption Angstrom Exponent for Source Apportionment of Equivalent Black Carbon: a Case Study from the North West Indo-Gangetic Plain

2015 ◽  
Vol 50 (2) ◽  
pp. 814-824 ◽  
Author(s):  
Saryu Garg ◽  
Boggarapu Praphulla Chandra ◽  
Vinayak Sinha ◽  
Roland Sarda-Esteve ◽  
Valerie Gros ◽  
...  
Keyword(s):  
Black Carbon ◽  
Source Apportionment ◽  
Gangetic Plain ◽  
North West ◽  
Angstrom Exponent ◽  
The North ◽  
Ångström Exponent ◽  
Indo Gangetic Plain ◽  
Ångstrom Exponent

scholarly journals Airborne in situ measurements of aerosol size distributions and black carbon across the Indo-Gangetic Plain during SWAAMI–RAWEX

2020 ◽  
Vol 20 (14) ◽  
pp. 8593-8610 ◽  
Author(s):  
Mukunda Madhab Gogoi ◽  
Venugopalan Nair Jayachandran ◽  
Aditya Vaishya ◽  
Surendran Nair Suresh Babu ◽  
Sreedharan Krishnakumari Satheesh ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Fraction ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Gangetic Plain ◽  
Airborne Measurements ◽  
Coarse Mode ◽  
Indo Gangetic Plain ◽  
Very High ◽  
Mass Concentrations

Abstract. During the combined South-West Asian Aerosol–Monsoon Interactions and Regional Aerosol Warming Experiment (SWAAMI–RAWEX), collocated airborne measurements of aerosol number–size distributions in the size (diameter) regime 0.5 to 20 µm and black carbon (BC) mass concentrations were made across the Indo-Gangetic Plain (IGP), for the first time, from three distinct locations, just prior to the onset of the Indian summer monsoon. These measurements provided an east–west transect of region-specific properties of aerosols as the environment transformed from mostly arid conditions of the western IGP (represented by Jodhpur, JDR) having dominance of natural aerosols to the central IGP (represented by Varanasi, VNS) having very high anthropogenic emissions, to the eastern IGP (represented by the coastal station Bhubaneswar, BBR) characterized by a mixture of the IGP outflow and marine aerosols. Despite these, the aerosol size distribution revealed an increase in coarse mode concentration and coarse mode mass fraction (fractional contribution to the total aerosol mass) with the increase in altitude across the entire IGP, especially above the well-mixed region. Consequently, both the mode radii and geometric mean radii of the size distributions showed an increase with altitude. However, near the surface and within the atmospheric boundary layer (ABL), the features were specific to the different subregions, with the highest coarse mode mass fraction (FMC∼72 %) in the western IGP and highest accumulation fraction in the central IGP with the eastern IGP in between. The elevated coarse mode fraction is attributed to mineral dust load arising from local production as well as due to advection from the west. This was further corroborated by data from the Cloud-Aerosol Transport System (CATS) on board the International Space Station (ISS), which also revealed that the vertical extent of dust aerosols reached as high as 5 km during this period. Mass concentrations of BC were moderate (∼1 µg m−3) with very little altitude variation up to 3.5 km, except over VNS where very high concentrations were seen near the surface and within the ABL. The BC-induced atmospheric heating rate was highest near the surface at VNS (∼0.81 K d−1), while showing an increasing pattern with altitude at BBR (∼0.35 K d−1 at the ceiling altitude).

scholarly journals Correlation of black carbon aerosol and carbon monoxide concentrations measured in the high-altitude environment of Mt. Huangshan, Eastern China

2011 ◽  
Vol 11 (2) ◽  
pp. 4447-4485 ◽  
Author(s):  
X. L. Pan ◽  
Y. Kanaya ◽  
Z. F. Wang ◽  
Y. Liu ◽  
P. Pochanart ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
High Altitude ◽  
Black Carbon ◽  
Urban Areas ◽  
Southern China ◽  
Eastern China ◽  
Back Trajectory ◽  
Strong Positive Correlation ◽  
Air Mass ◽  
Co Concentration

Abstract. Understanding the relationship between black carbon (BC) and carbon monoxide (CO) will help improve BC emission inventories and the evaluation of global/regional climate forcing effects. In the present work, the BC (PM1) and CO mixing ratio was continuously measured at a~high-altitude background station on the summit of Mt Huangshan between 2006 and 2009. Annual mean BC concentration was 654.6 ± 633.4 ng m−3 with maxima in spring and autumn, when biomass was burned over a large area in Eastern China. The yearly averaged CO concentration was 446.4 ± 167.6 ppbv, and the increase in the CO concentration was greatest in the cold season, implying that the large-scale domestic coal/biofuel combustion for heating has an effect. The BC–CO relationship was found to have different seasonal features but strong positive correlation (R > 0.8). Back trajectory cluster analysis showed that the ΔBC/ΔCO ratio of plumes from the Yangtze River Delta region was 6.58 ± 0.96 ng m−3 ppbv−1, which is consistent with result from INTEX-B emission inventory. The ΔBC/ΔCO ratios for air masses from Northern, Central Eastern and Southern China were 5.2 ± 0.63, 5.65 ± 0.58 and 5.21 ± 0.93 ng m−3 ppbv−1, respectively. Over the whole observation period, the ΔBC/ΔCO ratio had unimodal diurnal variations and had a maximum during the day (09:00–17:00 LST) and minimum at night (21:00–04:00 LST) in spring, summer, autumn and winter, indicating the effects of the intrusion of clean air mass from the high troposphere. The case study combined with measurements of urban PM10 concentrations and satellite observations demonstrated that the ΔBC/ΔCO ratio for a plume of burning biomass was 12.4 ng m−3 ppbv−1 and that for urban plumes in Eastern China was 5.3 ± 0.53 ng m−3 ppbv−1. Transportation and industry were deemed as controlling factors of the BC–CO relationship and major contributions to atmospheric BC and CO loadings in urban areas. The loss of BC during transportation was also investigated on the basis of the ΔBC/ΔCO–RH relationship along air mass pathways, and the results showed that 30–50% BC was lost when air mass traveled under higher RH conditions (>60%) for 2 days.

scholarly journals Vertical and horizontal distribution of sub-micron aerosol chemical composition and physical characteristics across Northern India, during the pre-monsoon and monsoon seasons

2018 ◽  
pp. 1-31
Author(s):  
James Brooks ◽  
James D. Allan ◽  
Paul I. Williams ◽  
Dantong Liu ◽  
Cathryn Fox ◽  
...  
Keyword(s):  
Black Carbon ◽  
Total Mass ◽  
Mass Concentration ◽  
Monsoon Season ◽  
Aerosol Layer ◽  
Gangetic Plain ◽  
Submicron Aerosol ◽  
Aerosol Mass ◽  
Indo Gangetic Plain ◽  
Mass Concentrations

<p><strong>Abstract.</strong> The vertical distribution in the physical and chemical properties of submicron aerosol has been characterised across northern India for the first time using airborne in-situ measurements. This study focusses primarily on the Indo-Gangetic Plain, a low-lying area in the north of India which commonly experiences high aerosol mass concentrations prior to the monsoon season. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights in the region during the 2016 pre-monsoon (11<sup>th</sup> and 12<sup>th</sup> June) and monsoon (30<sup>th</sup> June to 11<sup>th</sup> July) seasons.</p> <p> Inside the Indo-Gangetic Plain boundary layer, organic matter dominated the submicron aerosol mass (43&amp;thinsp;%) followed by sulphate (29&amp;thinsp;%), ammonium (14&amp;thinsp;%), nitrate (7&amp;thinsp;%) and black carbon (7&amp;thinsp;%). However, outside the Indo-Gangetic Plain, sulphate was the dominant species contributing 44&amp;thinsp;% to the total submicron aerosol mass in the boundary layer, followed by organic matter (30&amp;thinsp;%), ammonium (14&amp;thinsp;%), nitrate (6&amp;thinsp;%) and black carbon (6&amp;thinsp;%). Chlorine mass concentrations were negligible throughout the campaign. Black carbon mass concentrations were higher inside the Indo-Gangetic Plain (2&amp;thinsp;µg/m<sup>3</sup> std) compared to outside (1&amp;thinsp;µg/m<sup>3</sup> std). Nitrate appeared to be controlled by thermodynamic processes, with increased mass concentration in conditions of lower temperature and higher relative humidity. Increased mass and number concentrations were observed inside the Indo-Gangetic Plain and the aerosol was more absorbing in this region, whereas outside the Indo-Gangetic Plain the aerosol was larger in size and more scattering in nature, suggesting greater dust presence especially in northwest India. The aerosol composition remained largely similar as the monsoon season progressed, but the total aerosol mass concentrations decreased by ~&amp;thinsp;50&amp;thinsp;% as the rainfall arrived; the pre-monsoon average total mass concentration was 30&amp;thinsp;µg/m<sup>3</sup> std compared to a monsoon average total mass concentration of 10&amp;ndash;20&amp;thinsp;µg/m<sup>3</sup> std. However, this mass concentration decrease was less noteworthy (~&amp;thinsp;20&amp;ndash;30&amp;thinsp;%) over the Indo-Gangetic Plain, likely due to the strength of emission sources in this region. Decreases occurred in coarse mode aerosol, with the fine mode fraction increasing with monsoon arrival. In the aerosol vertical profile, inside the Indo-Gangetic Plain during the pre-monsoon, organic aerosol and absorbing aerosol species dominated in the lower atmosphere (<&amp;thinsp;1.5&amp;thinsp;km) with sulphate, dust and other scattering aerosol species enhanced in an elevated aerosol layer above 1.5&amp;thinsp;km with maximum aerosol height ~&amp;thinsp;6&amp;thinsp;km. As the monsoon progressed into this region, the elevated aerosol layer diminished, the aerosol maximum height reduced to ~&amp;thinsp;2&amp;thinsp;km and the total mass concentrations decreased by ~&amp;thinsp;50&amp;thinsp;%. The dust and sulphate-dominated aerosol layer aloft was removed upon monsoon arrival, highlighted by an increase in fine mode fraction throughout the profile.</p>

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