scholarly journals Non-methane hydrocarbon (NMHC) fingerprints of major urban and agricultural emission sources for use in source apportionment studies

2020 ◽  
Vol 20 (20) ◽  
pp. 12133-12152
Author(s):  
Ashish Kumar ◽  
Vinayak Sinha ◽  
Muhammed Shabin ◽  
Haseeb Hakkim ◽  
Bernard Bonsang ◽  
...  
Keyword(s):  
South Asia ◽  
Source Apportionment ◽  
Emission Sources ◽  
Vehicular Emissions ◽  
Liquefied Petroleum Gas ◽  
Multiple Sources ◽  
Formation Potential ◽  
Fire Emissions ◽  
Chemical Tracers ◽  
Evaporative Emissions

Abstract. In complex atmospheric emission environments such as urban agglomerates, multiple sources control the ambient chemical composition driving air quality and regional climate. In contrast to pristine sites, where reliance on single or a few chemical tracers is often adequate for resolving pollution plumes and source influences, the comprehensive chemical fingerprinting of sources using non-methane hydrocarbons (NMHCs) and the identification of suitable tracer molecules and emission ratios becomes necessary. Here, we characterise and present chemical fingerprints of some major urban and agricultural emission sources active in South Asia, such as paddy stubble burning, garbage burning, idling vehicular exhaust and evaporative fuel emissions. A total of 121 whole air samples were actively collected from the different emission sources in passivated air sampling steel canisters and then analysed for 49 NMHCs (22 alkanes, 16 aromatics, 10 alkenes and one alkyne) using thermal desorption gas chromatography flame ionisation detection. Several new insights were obtained. Propane was found to be present in paddy stubble fire emissions (8 %), and therefore, for an environment impacted by crop residue fires, the use of propane as a fugitive liquefied petroleum gas (LPG) emission tracer must be done with caution. Propene was found to be ∼ 1.6 times greater (by weight) than ethene in smouldering paddy fires. Compositional differences were observed between evaporative emissions of domestic LPG and commercial LPG, which are used in South Asia. While the domestic LPG vapours had more propane (40 ± 6 %) than n-butane (19 ± 2 %), the converse was true for commercial LPG vapours (7 ± 6 % and 37 ± 4 %, respectively). Isoprene was identified as a new tracer for distinguishing paddy stubble and garbage burning in the absence of isoprene emissions at night from biogenic sources. Analyses of source-specific inter-NMHC molar ratios revealed that toluene/benzene ratios can be used to distinguish among paddy stubble fire emissions in the flaming (0.38 ± 0.11) and smouldering stages (1.40 ± 0.10), garbage burning flaming (0.26 ± 0.07) and smouldering emissions (0.59 ± 0.16), and traffic emissions (3.54 ± 0.21), whereas i-pentane ∕ n-pentane can be used to distinguish biomass burning emissions (0.06–1.46) from the petrol-dominated traffic and fossil fuel emissions (2.83–4.13). i-butane ∕ n-butane ratios were similar (0.20–0.30) for many sources and could be used as a tracer for photochemical ageing. In agreement with previous studies, i-pentane, propane and acetylene were identified as suitable chemical tracers for petrol vehicular and evaporative emissions, LPG evaporative and vehicular emissions and flaming-stage biomass fires, respectively. The secondary pollutant formation potential and human health impact of the sources was also assessed in terms of their hydroxyl radical (OH) reactivity (s−1), ozone formation potential (OFP; gO3/gNMHC) and fractional benzene, toluene, ethylbenzene and xylenes (BTEX) content. Petrol vehicular emissions, paddy stubble fires and garbage fires were found to have a higher pollution potential (at ≥95 % confidence interval) relative to the other sources studied in this work. Thus, many results of this study provide a new foundational framework for quantitative source apportionment studies in complex emission environments.

scholarly journals Non methane hydrocarbon (NMHC) fingerprints of major urban and agricultural emission sources active in South Asia for use in source apportionment studies

2020 ◽  
Author(s):  
Ashish Kumar ◽  
Vinayak Sinha ◽  
Muhammed Shabin ◽  
Haseeb Hakkim ◽  
Bernard Bonsang ◽  
...  
Keyword(s):  
South Asia ◽  
Source Apportionment ◽  
Ambient Air ◽  
Exhaust Emissions ◽  
Emission Sources ◽  
Formation Potential ◽  
Fire Emissions ◽  
Chemical Tracers ◽  
Evaporative Emissions ◽  
Vehicular Exhaust

Abstract. In complex atmospheric emission environments such as urban agglomerates, multiple sources control the ambient chemical composition driving air quality and regional climate. In contrast to pristine sites, where reliance on single or few chemical tracers is often adequate to resolve pollution plumes and source influences, comprehensive chemical fingerprinting of sources using non-methane hydrocarbons and identification of suitable tracer molecule/molecules and emission ratios is necessary. Here, we characterize and present chemical fingerprints of some major urban and agricultural emission sources active in South Asia such as paddy stubble burning, garbage burning, idling vehicular exhaust and evaporative fuel emissions. Whole air samples were collected actively from the emission sources in passivated air sampling steel canisters and then analyzed for 49 NMHCs (22 alkanes, 16 aromatics, 10 alkene and 1 alkyne) using thermal desorption gas chromatography flame ionisation detection (TD-GC-FID). Based on the measured source profiles, chemical tracers were identified for distinguishing varied emission sources and also for use in PMF source apportionment models. Thus, we were able to identify chemical tracers such as i-pentane for petrol vehicular exhaust and evaporative emissions, propane for LPG evaporative and LPG vehicular exhaust emissions, and acetylene for the biomass fires during the flaming stage. Furthermore, we observed propane to be a major NMHC emission (8 %) from paddy stubble fires and therefore in an emission environment impacted by crop residue fires, use of propane as a fugitive LPG emission tracer requires caution. Isoprene was identified as a potential tracer for distinguishing paddy stubble and garbage burning in the absence of isoprene emissions at night from biogenic sources. Diesel vehicular exhaust comprised of > 50 % alkenes and alkyne by mass composition while diesel evaporative emissions were enriched in C5–C8 alkanes and aromatics. The secondary pollutant formation potential and human health impact of the sources was also assessed in terms of their OH reactivity (s−1), ozone formation potential (OFP, gO3/gNMHC) and fractional BTEX content. Petrol vehicular exhaust emissions, paddy stubble fires and garbage fires were identified as the most polluting among the sources studied in this work. Source specific inter-NMHC molar ratios which are often employed for identifying ambient air pollution emission plumes and assessing photochemical ageing were also examined. Toluene / benzene (T / B) ratios were a good tracer for distinguishing the paddy stubble fire emissions in flaming (0.42) and smoldering stages (1.39), garbage burning emissions (0.21–0.32) and traffic emissions (3.54). While i-butane / n-butane ratios were found to be similar (0.20–0.30) for many sources, i-pentane / n-pentane ratios were useful for distinguishing biomass burning emissions (0.09–0.70) from the traffic/fossil fuel emissions (1.55–8.77). The results of this study provide a new foundational framework for quantitative source apportionment studies in complex emission environments such as South Asia.

scholarly journals Reactive oxygen species associated with water-soluble PM2.5 in the southeastern United States: spatiotemporal trends and source apportionment

2014 ◽  
Vol 14 (13) ◽  
pp. 19625-19672 ◽  
Author(s):  
V. Verma ◽  
T. Fang ◽  
H. Guo ◽  
L. King ◽  
J. T. Bates ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Particulate Matter ◽  
Source Apportionment ◽  
Biomass Burning ◽  
Reactive Oxygen ◽  
Water Soluble ◽  
Ros Generation ◽  
Emission Sources ◽  
Vehicular Emissions ◽  
Oxygen Species

Abstract. We assess the potential of the water-soluble fraction of atmospheric fine aerosols in the southeastern US to generate reactive oxygen species (ROS) and identify major ROS-associated emission sources. ROS-generation potential of particles was quantified by the dithiothreitol (DTT) assay and involved analysis of fine particulate matter (PM) extracted from high-volume quartz filters (23 h integrated samples) collected at various sites in different environmental settings in the southeast, including three urban Atlanta sites, in addition to a rural site. Paired sampling was conducted with one fixed site in Atlanta (Jefferson Street), representative of the urban environment, with the others rotating among different sites, for ~250 days between June 2012 and September 2013 (N = 483). A simple linear regression between the DTT activity and aerosol chemical components revealed strong associations between PM ROS generation potential and secondary organic aerosol (WSOC) in summer, and biomass burning markers in winter. Redox-active metals were also correlated with the DTT activity, but mostly at urban and roadside sites. Positive matrix factorization (PMF) was applied to apportion the relative contribution of various sources to the ROS generation potential of water-soluble PM2.5 in urban Atlanta. PMF showed that vehicular emissions contribute uniformly throughout the year (12 to 25%), while secondary oxidation processes dominated the DTT activity in summer (46%) and biomass burning in winter (47%). Mineral dust was significant only during drier periods (~12% in summer and fall). Source apportionment by chemical mass balance (CMB) was reasonably consistent with PMF, but with higher contribution from vehicular emissions (32%). Given the spatially large data set of PM sampled over an extended period, the study reconciles the results from previous work that showed only region- or season-specific aerosol components or sources contributing to PM ROS activity, possibly due to smaller sample sizes. Our results indicate that the ability to generate ROS is a generic property of fine PM to which almost all major emission sources contribute to variable extents. The ubiquitous nature of the ROS generation property of ambient particulate matter suggests widespread population exposures to aerosol components that have the ability to catalyze the production of oxidants in vivo.

scholarly journals Emission factor, relative ozone formation potential and relative carcinogenic risk assessment of VOCs emitted from manufacturing industries

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Hsi-Hsien Yang ◽  
Sunil Kumar Gupta ◽  
Narayan Babu Dhital
Keyword(s):  
Acrylic Resin ◽  
Carcinogenic Risk ◽  
Manufacturing Industries ◽  
Emission Sources ◽  
Ozone Formation ◽  
Stencil Printing ◽  
Voc Emission ◽  
Formation Potential ◽  
Ozone Formation Potential ◽  
Level I

AbstractManufacturing industries are one of the important emission sectors of anthropogenic volatile organic compounds (VOCs). In this study, VOC emission factors, relative ozone formation potential (ROFP) and relative carcinogenic risk (RCR) were estimated for manufacturing industries (n = 13) located in central Taiwan. Emission samples were collected in stainless steel canisters and were analyzed with a system of gas chromatography-mass spectroscopy. Higher emission factors of total VOCs (∑VOCs) were observed for stencil printing (423 mg-VOC kg− 1) compared to other emission industries. Alkanes constituted the most prominent group of VOCs for steel foundry (42%), aluminum foundry (25%) and synthetic resin industries (25%). Oxygenated VOCs were the most abundant group in the organic solvent (80%), polyester resin (80%) and polyurethane (75%) industries. Moreover, emissions from acrylic resin manufacturing had a major contribution from aromatic compounds (> 95%). Toluene was the topmost compound in terms of its contribution to ∑VOCs in plastic tape manufacturing (44%), aluminum foundry (40%), steel foundry (12%), plastic coating (64%) and stencil printing (35%). Analysis of ozone formation potentials showed that the metal product and machinery acrylic resin manufacturing and stencil printing had a higher normalized relative ozone formation potential (ROFP) index and belonged to Level-I emission sources. However, in terms of the relative carcinogenic risk (RCR), integrated iron and steel manufacturing had the highest normalized RCR index that belonged to level-I emission sources. Level-I represents the most important VOC emission sources. This study provides a reactivity- and carcinogenicity-based approach to identify high-priority VOC emission sources. The results of this study would help formulate emission reduction policies and strategies for manufacturing industries.

scholarly journals Year-round radiocarbon-based source apportionment of carbonaceous aerosols at two background sites in South Asia

2012 ◽  
Vol 117 (D10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Rebecca J. Sheesley ◽  
Elena Kirillova ◽  
August Andersson ◽  
Martin Kruså ◽  
P. S. Praveen ◽  
...  
Keyword(s):  
South Asia ◽  
Source Apportionment ◽  
Carbonaceous Aerosols

scholarly journals Towards monitoring localized CO<sub>2</sub> emissions from space: co-located regional CO<sub>2</sub> and NO<sub>2</sub> enhancements observed by the OCO-2 and S5P satellites

2019 ◽  
Author(s):  
Maximilian Reuter ◽  
Michael Buchwitz ◽  
Oliver Schneising ◽  
Sven Krautwurst ◽  
Christopher W. O'Dell ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Power Plants ◽  
Fossil Fuels ◽  
Open Data ◽  
Point Sources ◽  
Background Concentration ◽  
Multiple Sources ◽  
Cross Sectional ◽  
Fire Emissions ◽  
Dry Air

Abstract. Despite its key role for climate change, large uncertainties persist in our knowledge of the anthropogenic emissions of carbon dioxide (CO2) and no global observing system exists allowing to monitor emissions from localized CO2 sources with sufficient accuracy. The Orbiting Carbon Observatory-2 (OCO-2) satellite can retrieve the column-average dry-air mole fractions of CO2 (XCO2). However, regional column-average enhancements of individual point sources are usually small compared to the background concentration and its natural variability. This makes the unambiguous identification and quantification of anthropogenic emission plume signals challenging. NO2 is co-emitted with CO2 when fossil fuels are combusted at high temperatures. It has a short lifetime of the order of hours so that NO2 columns often exceed background levels by orders of magnitude near sources making it a suitable tracer of recently emitted CO2. Based on six case studies (Moscow, Russia; Lipetsk, Russia; Baghdad, Iraq; Medupi and Matimba power plants, South Africa; Australian wildfires; and Nanjing, China), we demonstrate the usefulness of simultaneous satellite observations of NO2 and the column-average dry-air mole fraction of CO2 (XCO2). For this purpose, we analyze co-located regional enhancements of XCO2 observed by OCO-2 and NO2 observed by the Sentinel-5 Precursor (S5P) satellite and estimate the CO2 plume's cross-sectional fluxes. We take advantage of the nearly simultaneous NO2 measurements with S5P's wide swath by identifying the source of the observed XCO2 enhancements, excluding interference with remote upwind sources, allowing to adjust the wind direction, and by constraining the shape of the CO2 plumes. We compare the inferred cross-sectional fluxes with the Emissions Database for Global Atmospheric Research (EDGAR), the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC), and, in the case of the Australian wildfires, with the Global Fire Emissions Database (GFED). The inferred cross-sectional fluxes range from 32 Mt CO2/a to 158 Mt CO2/a with uncertainties (1σ) between 23 % and 72 %. For the majority of analyzed emission sources, the estimated cross-sectional fluxes agree within their uncertainty with either EDGAR or ODIAC or lie in between them. We assess the contribution of multiple sources of uncertainty and find that the dominating contributions are related to the computation of the effective wind speed normal to the plume's cross-section. The planned European Copernicus anthropogenic CO2 monitoring mission (CO2M) will not only provide precise measurements with high spatial resolution but also imaging capabilities with a wider swath of simultaneous XCO2 and NO2 observations. Such a mission, in particular as a constellation of satellites, will deliver CO2 emission estimates from localized sources at an unprecedented frequency and level of accuracy.

scholarly journals Reactive oxygen species associated with water-soluble PM<sub>2.5</sub> in the southeastern United States: spatiotemporal trends and source apportionment

2014 ◽  
Vol 14 (23) ◽  
pp. 12915-12930 ◽  
Author(s):  
V. Verma ◽  
T. Fang ◽  
H. Guo ◽  
L. King ◽  
J. T. Bates ◽  
...  
Keyword(s):  
United States ◽  
Reactive Oxygen Species ◽  
Source Apportionment ◽  
Biomass Burning ◽  
Southeastern United States ◽  
Reactive Oxygen ◽  
Water Soluble ◽  
Ros Generation ◽  
Vehicular Emissions ◽  
Oxygen Species

Abstract. We assess the potential of the water-soluble fraction of atmospheric fine aerosols in the southeastern United States to generate reactive oxygen species (ROS) and identify major ROS-associated emission sources. ROS-generation potential of particles was quantified by the dithiothreitol (DTT) assay and involved analysis of fine particulate matter (PM) extracted from high-volume quartz filters (23 h integrated samples) collected at various sites in different environmental settings in the southeast, including three urban-Atlanta sites, in addition to a rural site. Paired sampling was conducted with one fixed site in Atlanta (Jefferson Street), representative of the urban environment, with the others rotating among different sites, for ~250 days between June 2012 and September 2013 (N=483). A simple linear regression between the DTT activity and aerosol chemical components revealed strong associations between PM ROS-generation potential and secondary organic aerosol (WSOC – water-soluble organic carbon) in summer, and biomass burning markers in winter. Redox-active metals were also somewhat correlated with the DTT activity, but mostly at urban and roadside sites. Positive matrix factorization (PMF) was applied to apportion the relative contribution of various sources to the ROS-generation potential of water-soluble PM2.5 in urban Atlanta. PMF showed that vehicular emissions contribute uniformly throughout the year (12–25%), while secondary oxidation processes dominated the DTT activity in summer (46%) and biomass burning in winter (47%). Road dust was significant only during drier periods (~12% in summer and fall). Source apportionment by chemical mass balance (CMB) was reasonably consistent with PMF, but with higher contribution from vehicular emissions (32%). Given the spatially large data set of PM sampled over an extended period, the study reconciles the results from previous work that showed only region- or season-specific aerosol components or sources contributing to PM ROS activity, possibly due to smaller sample sizes. The ubiquitous nature of the major sources of PM-associated ROS suggests widespread population exposures to aerosol components that have the ability to catalyze the production of oxidants in vivo.

scholarly journals Towards monitoring localized CO<sub>2</sub> emissions from space: co-located regional CO<sub>2</sub> and NO<sub>2</sub> enhancements observed by the OCO-2 and S5P satellites

2019 ◽  
Vol 19 (14) ◽  
pp. 9371-9383 ◽  
Author(s):  
Maximilian Reuter ◽  
Michael Buchwitz ◽  
Oliver Schneising ◽  
Sven Krautwurst ◽  
Christopher W. O'Dell ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Power Plants ◽  
Fossil Fuels ◽  
Open Data ◽  
Point Sources ◽  
Measurement Noise ◽  
Background Concentration ◽  
Multiple Sources ◽  
Cross Sectional ◽  
Fire Emissions

Abstract. Despite its key role in climate change, large uncertainties persist in our knowledge of the anthropogenic emissions of carbon dioxide (CO2) and no global observing system exists that allows us to monitor emissions from localized CO2 sources with sufficient accuracy. The Orbiting Carbon Observatory-2 (OCO-2) satellite allows retrievals of the column-average dry-air mole fractions of CO2 (XCO2). However, regional column-average enhancements of individual point sources are usually small, compared to the background concentration and its natural variability, and often not much larger than the satellite's measurement noise. This makes the unambiguous identification and quantification of anthropogenic emission plume signals challenging. NO2 is co-emitted with CO2 when fossil fuels are combusted at high temperatures. It has a short lifetime on the order of hours so that NO2 columns often greatly exceed background and noise levels of modern satellite sensors near sources, which makes it a suitable tracer of recently emitted CO2. Based on six case studies (Moscow, Russia; Lipetsk, Russia; Baghdad, Iraq; Medupi and Matimba power plants, South Africa; Australian wildfires; and Nanjing, China), we demonstrate the usefulness of simultaneous satellite observations of NO2 and XCO2. For this purpose, we analyze co-located regional enhancements of XCO2 observed by OCO-2 and NO2 from the Sentinel-5 Precursor (S5P) satellite and estimate the CO2 plume's cross-sectional fluxes. We take advantage of the nearly simultaneous NO2 measurements with S5P's wide swath and small measurement noise by identifying the source of the observed XCO2 enhancements, excluding interference with remote upwind sources, allowing us to adjust the wind direction, and by constraining the shape of the CO2 plumes. We compare the inferred cross-sectional fluxes with the Emissions Database for Global Atmospheric Research (EDGAR), the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC), and, in the case of the Australian wildfires, with the Global Fire Emissions Database (GFED). The inferred cross-sectional fluxes range from 31 MtCO2 a−1 to 153 MtCO2 a−1 with uncertainties (1σ) between 23 % and 72 %. For the majority of analyzed emission sources, the estimated cross-sectional fluxes agree, within their uncertainty, with either EDGAR or ODIAC or lie somewhere between them. We assess the contribution of multiple sources of uncertainty and find that the dominating contributions are related to the computation of the effective wind speed normal to the plume's cross section. The flux uncertainties are expected to be reduced by the planned European Copernicus anthropogenic CO2 monitoring mission (CO2M), which will provide not only precise measurements with high spatial resolution but also imaging capabilities with a wider swath of simultaneous XCO2 and NO2 observations. Such a mission, particularly if performed by a constellation of satellites, will deliver CO2 emission estimates from localized sources at an unprecedented frequency and level of accuracy.

scholarly journals Are contributions of emissions to ozone a matter of scale? – A study using MECO(n) (MESSy v2.50)

2019 ◽  
Author(s):  
Mariano Mertens ◽  
Astrid Kerkweg ◽  
Volker Grewe ◽  
Patrick Jöckel ◽  
Robert Sausen
Keyword(s):  
Source Apportionment ◽  
Emission Inventory ◽  
Climate Model ◽  
Ground Level ◽  
Emission Sources ◽  
Emission Inventories ◽  
Anthropogenic Emission ◽  
Model Resolution ◽  
Ground Level Ozone ◽  
Transport Emissions

Abstract. Anthropogenic and natural emissions influence the tropospheric ozone budget, thereby affecting air-quality and climate. To study the influence of different emission sources on the ozone budget, often source apportionment studies with a tagged tracer approach are performed. Studies investigating air quality issues usually rely on regional models with a high spatial resolution, while studies focusing on climate related questions often use coarsely resolved global models. It is well known that simulated ozone concentrations depend on the resolution of the model and the resolution of the emission inventory. Whether the contributions simulated by source apportionment approaches also depend on the model resolution, however, is still unclear. Therefore, this study is a first attempt to analyse the impact of the model, the model resolution, and the emission inventory resolution on simulated ozone contributions diagnosed with a tagging method. The differences of the ozone contributions caused by these factors are compared with differences which arise due to different emission inventories. To do so we apply the MECO(n) model system which on-line couples a global chemistry-climate model with a regional chemistry-climate model equipped with a tagging scheme for source apportionment. The results of the global model (300 km resolution) are compared with the results of the regional model at 50 km (Europe) and 12 km (Germany) resolution. Averaged over Europe the simulated contributions of land transport emissions to ground-level ozone differ by 10 % at maximum. For other anthropogenic emission sources the differences are in the same order of magnitude, while the contribution of stratospheric ozone to ground level ozone differs by up to 30 % on average. This suggests that ozone contributions of anthropogenic emission sources averaged on continental scale are rather robust with respect to different models, model and emission inventory resolutions. On regional scale, however, we quantified differences of the contribution of land transport emissions to ozone of up to 20 %. Depending on the region the largest differences are either caused by inter model differences, or differences of the anthropogenic emission inventories. Clearly, the results strongly depend on the compared models and emission inventories and cannot necessarily be generalised, however we show how the inclusion of source apportionment methods can help in analysing inter-model differences.

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