scholarly journals Pedestrian exposure to black carbon and PM2.5 emissions in urban hot spots: new findings using mobile measurement techniques and flexible Bayesian regression models

2021 ◽  
Author(s):  
Honey Dawn Alas ◽  
Almond Stöcker ◽  
Nikolaus Umlauf ◽  
Oshada Senaweera ◽  
Sascha Pfeifer ◽  
...  
Keyword(s):  
Black Carbon ◽  
Urban Areas ◽  
Measurement Techniques ◽  
Bayesian Regression ◽  
Spatially Resolved ◽  
Pollutant Concentrations ◽  
New Findings ◽  
Mean And Variance ◽  
Instrument Measurement ◽  
Mass Concentrations

Abstract Background Data from extensive mobile measurements (MM) of air pollutants provide spatially resolved information on pedestrians’ exposure to particulate matter (black carbon (BC) and PM2.5 mass concentrations). Objective We present a distributional regression model in a Bayesian framework that estimates the effects of spatiotemporal factors on the pollutant concentrations influencing pedestrian exposure. Methods We modeled the mean and variance of the pollutant concentrations obtained from MM in two cities and extended commonly used lognormal models with a lognormal-normal convolution (logNNC) extension for BC to account for instrument measurement error. Results The logNNC extension significantly improved the BC model. From these model results, we found local sources and, hence, local mitigation efforts to improve air quality, have more impact on the ambient levels of BC mass concentrations than on the regulated PM2.5. Significance Firstly, this model (logNNC in bamlss package available in R) could be used for the statistical analysis of MM data from various study areas and pollutants with the potential for predicting pollutant concentrations in urban areas. Secondly, with respect to pedestrian exposure, it is crucial for BC mass concentration to be monitored and regulated in areas dominated by traffic-related air pollution.

scholarly journals Black carbon measurements in the boundary layer over western and northern Europe

2010 ◽  
Vol 10 (6) ◽  
pp. 13797-13853 ◽  
Author(s):  
G. R. McMeeking ◽  
T. Hamburger ◽  
D. Liu ◽  
M. Flynn ◽  
W. T. Morgan ◽  
...  
Keyword(s):  
Physical Properties ◽  
Black Carbon ◽  
Light Absorption ◽  
Urban Areas ◽  
Global Climate ◽  
Lower Troposphere ◽  
Climate Impacts ◽  
Air Mass ◽  
Lack Of Information ◽  
Mass Concentrations

Abstract. Europe is a densely populated region that is a significant global source of black carbon (BC) aerosol, but there is a lack of information regarding the physical properties and spatial/vertical distribution of BC in the region. We present the first aircraft observations of sub-micron BC aerosol concentrations and physical properties measured by a single particle soot photometer (SP2) in the lower troposphere over Europe. The observations spanned a region roughly bounded by 50° to 60° N and from 15° W to 30° E. The measurements, made between April and September 2008, showed that average BC mass concentrations ranged from about 300 ng m−3 near urban areas to approximately 50 ng m−3 in remote continental regions, lower than previous surface-based measurements. BC represented between 0.5 and 3% of the sub-micron aerosol mass. Black carbon mass size distributions were log-normally distributed and peaked at approximately 180 nm, but shifted to smaller diameters (~160 nm) near source regions. Black carbon was correlated with carbon monoxide (CO) but had different ratios to CO depending on location and air mass. Light absorption coefficients were measured by particle soot absorption photometers on two separate aircraft and showed similar geographic patterns to BC mass measured by the SP2, but differed by at least a factor of two compared to each other. We summarize the BC and light absorption measurements as a function of longitude and air mass age and also provide profiles of BC mass concentrations and size distribution statistics. Our results will help evaluate model-predicted regional BC concentrations and properties and determine regional and global climate impacts from BC due to atmospheric heating and surface dimming.

Representativeness and variability of PM2.5 mass concentrations and black carbon near traffic and urban background monitoring stations/Repräsentativität und Variabilität von PM2.5-Massenkonzentrationen und schwarzem Kohlenstoff in der Nähe von Verkehrs- und städtischen Luftgütemessstationen.

Gefahrstoffe ◽  
2019 ◽  
Vol 79 (06) ◽  
pp. 217-226
Author(s):  
H. D. Alas ◽  
S. Pfeifer ◽  
A. Wiesner ◽  
B. Wehner ◽  
K. Weinhold ◽  
...  
Keyword(s):  
Air Pollution ◽  
Black Carbon ◽  
Urban Areas ◽  
Mass Concentration ◽  
Spatial Distributions ◽  
Urban Background ◽  
Regular Monitoring ◽  
The City ◽  
Mass Concentrations ◽  
Monitoring Stations

Mobile measurements of PM2.5 and black carbon (BC) mass concentrations were performed near regular monitoring stations in order to gain deeper understanding of the drivers of pedestrian exposure to traffic-related air pollution. The following investigations have been done: A) Yearlong measurements in an area around a street canyon approximately 3 km airline distance from the city center of Leipzig showed that the spatial distributions of both pollutants are elevated during wintertime. The patterns of the BC mass concentration, however, consistently showed a strong influence from traffic emissions in the street, while the PM2.5 mass concentration was more dependent on the regional background and less on urban sources. B) Measurements in the city of Dresden near two regular monitoring stations, one at a roadside and one in urban background areas revealed differences between the two in terms of the BC mass concentrations, with slightly higher concentrations at the traffic area. However, no significant differences between the spatial distributions of PM2.5 mass concentrations were observed. The background measurements of the PM2.5 mass concentrations seem to be generally representative for the residential area. C) Measurements near a regular monitoring station located at a junction of the inner-city ring road of Leipzig showed that it is representative of its immediate vicinity in terms of BC mass concentrations. However, the PM2.5 mass concentration varied by a factor 2, reaching the highest levels near in the central tram station about 200 m away. The central tram station seems to significantly influence the PM2.5 mass concentration. These results of the three studies provide a better understanding of the variability of these two parameters in urban areas in Leipzig and Dresden, helping local policy makers to interpret better the measured air pollution.

scholarly journals Decreasing Trends of Particle Number and Black Carbon Mass Concentrations at 16 Observational Sites in Germany from 2009 to 2018

2019 ◽  
Author(s):  
Jia Sun ◽  
Wolfram Birmili ◽  
Markus Hermann ◽  
Thomas Tuch ◽  
Kay Weinhold ◽  
...  
Keyword(s):  
Time Series ◽  
Black Carbon ◽  
Urban Areas ◽  
Mass Concentration ◽  
Particle Number ◽  
Regional Scale ◽  
Particle Diameter ◽  
Anthropogenic Emissions ◽  
Mitigation Policies ◽  
Mass Concentrations

Abstract. Anthropogenic emissions are a dominant contributor to air pollution. Consequently, mitigation policies have attempted to reduce anthropogenic pollution emissions in Europe since the 1990s. To evaluate the effectiveness of these mitigation policies, the German Ultrafine Aerosol Network (GUAN) was established in 2008, focusing on black carbon and sub-micrometer aerosol particles, especially ultrafine particles. In this investigation, trends of the size-resolved particle number concentrations (PNC) and the equivalent black carbon (eBC) mass concentration over a 10-year period (2009–2018) were evaluated for 16 observational sites for different environments among GUAN. The trend analysis was done for both, the full-length time series and on subsets of the time series in order to test the reliability of the results. The results show generally decreasing trends of both, the PNCs for all size ranges as well as eBC mass concentrations in all environments, except PNC in 10–30 nm at regional background and mountain sites. The annual slope of the eBC mass concentration varies between −7.7 % and −1.8 % per year. The slopes of the PNCs varies from −6.3 % to 2.7 %, −7.0 % to −2.0 %, and −9.5 % to −1.5 % per year (only significant trends) for 10–30 nm, 30–200 nm, and 200–800 nm particle diameter, respectively. The regional Mann-Kendall test yielded regional-scale trends of eBC mass concentration, N[30–200] and N[200–800] of −3.8 %, −2.0 % and −2.4 %, respectively, indicating an overall decreasing trend for eBC mass concentration and sub-micrometer PNC (except N[10–30]) all over Germany. The most significant decrease was observed on working days and during daytime in urban areas, which implies a strong evidence of reduced anthropogenic emissions. For the seasonal trends, stronger reductions were observed in winter. Possible reasons for this reduction can be the increased average ambient temperatures and wind speed in winter, which resulted in less domestic heating and stronger dilution. In addition, decreased precipitation in summer also diminishes the decrease of the PNCs and eBC mass concentration. For the period of interest, there were no significant changes in long-range transport patterns. The most likely factors for the observed decreasing trends are declining anthropogenic emissions due to emission mitigation policies of the European Union.

scholarly journals Black carbon measurements in the boundary layer over western and northern Europe

2010 ◽  
Vol 10 (19) ◽  
pp. 9393-9414 ◽  
Author(s):  
G. R. McMeeking ◽  
T. Hamburger ◽  
D. Liu ◽  
M. Flynn ◽  
W. T. Morgan ◽  
...  
Keyword(s):  
Physical Properties ◽  
Black Carbon ◽  
Light Absorption ◽  
Urban Areas ◽  
Global Climate ◽  
Lower Troposphere ◽  
Climate Impacts ◽  
Air Mass ◽  
Lack Of Information ◽  
Mass Concentrations

Abstract. Europe is a densely populated region that is a significant global source of black carbon (BC) aerosol, but there is a lack of information regarding the physical properties and spatial/vertical distribution of rBC in the region. We present the first aircraft observations of sub-micron refractory BC (rBC) aerosol concentrations and physical properties measured by a single particle soot photometer (SP2) in the lower troposphere over Europe. The observations spanned a region roughly bounded by 50° to 60° N and from 15° W to 30° E. The measurements, made between April and September 2008, showed that average rBC mass concentrations ranged from about 300 ng m−3 near urban areas to approximately 50 ng m−3 in remote continental regions, lower than previous surface-based measurements. rBC represented between 0.5 and 3% of the sub-micron aerosol mass. Black carbon mass size distributions were log-normally distributed and peaked at approximately 180 nm, but shifted to smaller diameters (~160 nm) near source regions. rBC was correlated with carbon monoxide (CO) but had different ratios to CO depending on location and air mass. Light absorption coefficients were measured by particle soot absorption photometers on two separate aircraft and showed similar geographic patterns to rBC mass measured by the SP2. We summarize the rBC and light absorption measurements as a function of longitude and air mass age and also provide profiles of rBC mass concentrations and size distribution statistics. Our results will help evaluate model-predicted regional rBC concentrations and properties and determine regional and global climate impacts from rBC due to atmospheric heating and surface dimming.

scholarly journals Study of Temporal Variations of Equivalent Black Carbon in a Coastal City in Northwest Spain Using an Atmospheric Aerosol Data Management Software

2021 ◽  
Vol 11 (2) ◽  
pp. 516
Author(s):  
María Piñeiro-Iglesias ◽  
Javier Andrade-Garda ◽  
Sonia Suárez-Garaboa ◽  
Soledad Muniategui-Lorenzo ◽  
Purificación López-Mahía ◽  
...  
Keyword(s):  
Data Management ◽  
Black Carbon ◽  
Light Absorption ◽  
Atmospheric Aerosol ◽  
Urban Areas ◽  
Radiative Properties ◽  
Anthropogenic Sources ◽  
Biomass Combustion ◽  
Management Support ◽  
Diurnal Variability

Light-absorbing carbonaceous aerosols (including black carbon (BC)) pose serious health issues and play significant roles in atmospheric radiative properties. Two-year measurements (2015–2016) of aerosol light absorption, combined with measurements of sub-micrometric particles, were continuously conducted in A Coruña (northwest (NW) Spain) to determine their light absorption properties: absorption coefficients (σabs) and the absorption Ångström exponent (AAE). The mean and standard deviation of equivalent black carbon (eBC) during the period of study were 0.85 ± 0.83 µg m−3, which are lower than other values measured in urban areas of Spain and Europe. High eBC concentrations found in winter are associated with an increase in emissions from anthropogenic sources in combination with lower mixing layer heights and frequent stagnant conditions. The pronounced diurnal variability suggests a strong influence from local sources. AAE had an average value of 1.26 ± 0.22 which implies that both fossil fuel combustion and biomass burning influenced optical aerosol properties. This also highlights biomass combustion in suburban areas, where the use of wood for domestic heating is encouraged, as an important source of eBC. All data treatment was gathered using SCALA© as atmospheric aerosol data management support software program.

scholarly journals Assessing recent measurement techniques for quantifying black carbon concentration in snow

2012 ◽  
Vol 5 (3) ◽  
pp. 3771-3795 ◽  
Author(s):  
J. P. Schwarz ◽  
S. J. Doherty ◽  
F. Li ◽  
S. T. Ruggiero ◽  
C. E. Tanner ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Carbon Concentration ◽  
Mass Concentration ◽  
Measurement Techniques ◽  
Integrating Sphere ◽  
Recent Measurement ◽  
Atmospheric Sampling ◽  
Careful Assessment ◽  
Snow Samples

Abstract. We evaluate the performance of the Single Particle Soot Photometer (SP2) and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) in quantifying the concentration of refractory black carbon (BC) in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60%) than for atmospheric sampling (<30%). Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow tends to larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow and ice using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

scholarly journals Weekly patterns of México City's surface concentrations of CO, NO<sub>x</sub>, PM<sub>10</sub> and O<sub>3</sub> during 1986–2007

2008 ◽  
Vol 8 (17) ◽  
pp. 5313-5325 ◽  
Author(s):  
S. Stephens ◽  
S. Madronich ◽  
F. Wu ◽  
J. B. Olson ◽  
R. Ramos ◽  
...  
Keyword(s):  
Urban Areas ◽  
Distinct Pattern ◽  
Weekend Effect ◽  
The Past ◽  
Pollutant Concentrations ◽  
Photolysis Frequencies ◽  
Volatile Organic ◽  
The World ◽  
Urban Monitoring ◽  
Related Compounds

Abstract. Surface pollutant concentrations in México City show a distinct pattern of weekly variations similar to that observed in many other cities of the world. Measurements of the concentrations of carbon monoxide (CO), nitrogen oxides (NOx=NO+NO2), particulate matter smaller than 10 μm (PM10), and ozone (O3) collected hourly over 22 years (1986–2007) at 39 urban monitoring locations were analyzed. Morning concentrations of CO, NOx, and PM10 are lower on Saturdays and even more so on Sundays, compared to workdays (Monday–Friday), while afternoon O3 concentrations change minimally and are occasionally even higher. This weekend effect is empirical evidence that photochemical O3 production is NOx-inhibited, and to the extent that emissions of CO are proportional to those of reactive volatile organic compounds (VOCs), it is VOC-limited, at least in the urban areas for which the monitoring stations are representative. The VOC-limitation has increased in the past decade, due to decreases in the concentrations of CO (and presumably VOCs) and consequent decreases in the CO/NOx and VOC/NOx ratios. Enhancements of photolysis frequencies resulting from smaller weekend aerosol burdens are not negligible, but fall short of being an alternate explanation for the observed weekend effect. The strength of the weekend effect indicates that local radical termination occurs primarily via formation of nitric acid and other NOx-related compounds, some of which (e.g. peroxy acyl nitrates) can contribute to the regional NOx budget. While VOC emission reductions would be most effective in reducing local O3 production, NOx emission reduction may be more important for controlling regional oxidants.

scholarly journals Sources of black carbon aerosols in South Asia and surrounding regions during the Integrated Campaign for Aerosols, Gases and Radiation Budget (ICARB)

2015 ◽  
Vol 15 (10) ◽  
pp. 5415-5428 ◽  
Author(s):  
R. Kumar ◽  
M. C. Barth ◽  
V. S. Nair ◽  
G. G. Pfister ◽  
S. Suresh Babu ◽  
...  
Keyword(s):  
Spatial Variability ◽  
South Asia ◽  
Black Carbon ◽  
Biomass Burning ◽  
Regional Scale ◽  
Anthropogenic Sources ◽  
Radiation Budget ◽  
Anthropogenic Emissions ◽  
Spatial And Temporal Variability ◽  
Mass Concentrations

Abstract. This study examines differences in the surface black carbon (BC) aerosol loading between the Bay of Bengal (BoB) and the Arabian Sea (AS) and identifies dominant sources of BC in South Asia and surrounding regions during March–May 2006 (Integrated Campaign for Aerosols, Gases and Radiation Budget, ICARB) period. A total of 13 BC tracers are introduced in the Weather Research and Forecasting Model coupled with Chemistry to address these objectives. The model reproduced the temporal and spatial variability of BC distribution observed over the AS and the BoB during the ICARB ship cruise and captured spatial variability at the inland sites. In general, the model underestimates the observed BC mass concentrations. However, the model–observation discrepancy in this study is smaller compared to previous studies. Model results show that ICARB measurements were fairly well representative of the AS and the BoB during the pre-monsoon season. Elevated BC mass concentrations in the BoB are due to 5 times stronger influence of anthropogenic emissions on the BoB compared to the AS. Biomass burning in Burma also affects the BoB much more strongly than the AS. Results show that anthropogenic and biomass burning emissions, respectively, accounted for 60 and 37% of the average ± standard deviation (representing spatial and temporal variability) BC mass concentration (1341 ± 2353 ng m−3) in South Asia. BC emissions from residential (61%) and industrial (23%) sectors are the major anthropogenic sources, except in the Himalayas where vehicular emissions dominate. We find that regional-scale transport of anthropogenic emissions contributes up to 25% of BC mass concentrations in western and eastern India, suggesting that surface BC mass concentrations cannot be linked directly to the local emissions in different regions of South Asia.

scholarly journals Emission Factors of Black Carbon and Co-pollutants from Diesel Vehicles in Mexico City

2017 ◽  
Author(s):  
Miguel Zavala ◽  
Luisa T. Molina ◽  
Tara I. Yacovitch ◽  
Edward C. Fortner ◽  
Joseph R. Roscioli ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Developing Countries ◽  
Black Carbon ◽  
Mexico City ◽  
Urban Areas ◽  
Fine Particulate Matter ◽  
Emission Factors ◽  
Remote Sensing Technique ◽  
Driving Conditions ◽  
Comparison Of The Results

Abstract. Diesel-powered vehicles are intensively used in urban areas for transporting goods and people but can substantially contribute to high emissions of black carbon (BC), organic carbon (OC), and other gaseous pollutants. Strategies aimed at controlling mobile emissions sources thus have the potential to improve air quality as well as help mitigate impacts of air pollutants on climate, ecosystems, and human health. However, in developing countries there are limited data on the BC and OC emission characteristics of diesel-powered vehicles and thus there are large uncertainties in the estimation of the emission contributions from these sources. We measured BC, OC and other inorganic components of fine particulate matter (PM), as well as carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), ethane, acetylene, benzene, toluene, and C2-benzenes under real-world driving conditions of 20 diesel-powered vehicles encompassing multiple emission level technologies in Mexico City with the chasing technique using the Aerodyne mobile laboratory. Average BC emission factors ranged from 0.41–2.48 g/kg-fuel depending on vehicle type. The vehicles were also simultaneously measured using the cross-road remote sensing technique to obtain the emission factors of nitrogen oxide (NO), CO, total hydrocarbons, and fine PM, thus allowing the inter-comparison of the results from the two techniques. There is overall good agreement between the two techniques and both can identify high and low emitters but substantial differences were found in some of the vehicles, probably due to the ability of the chasing technique to capture a larger diversity of driving conditions in comparison to the remote sensing technique. A comparison of the results with the US-EPA MOVES-2014b model showed that the model underestimates CO, OC, and selected VOC species whereas there is better agreement for NOx and BC. Larger OC / BC ratios were found in comparison to ratios measured in California using the same technique, further demonstrating the need for using locally-obtained diesel-powered vehicle emission factors database in developing countries in order to reduce the uncertainty in the emissions estimates and to improve the evaluation of the effectiveness of emissions reduction measures.

scholarly journals Mixing state of refractory black carbon aerosol in the South Asian outflow over the northern Indian Ocean during winter

2020 ◽  
Author(s):  
Sobhan Kumar Kompalli ◽  
Surendran Nair Suresh Babu ◽  
Krishnaswamy Krishnamoorthy ◽  
Sreedharan Krishnakumari Satheesh ◽  
Mukunda M. Gogoi ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Black Carbon ◽  
South Asian ◽  
Arabian Sea ◽  
Equatorial Indian Ocean ◽  
Mixing State ◽  
Air Masses ◽  
Continental Outflow ◽  
Mass Concentrations

Abstract. Regional climatic implications of aerosol black carbon (BC) are well recognized over South Asia, which has a wide variety of anthropogenic sources in a large abundance. Significant uncertainties remain in its quantification due to lack of sufficient information on the microphysical properties (its concentration, size, and mixing state with other aerosol components), which determine the absorption potential of BC. Especially the information on mixing state of BC is extremely sparse over this region. In this study, first-ever observations of the size distribution and mixing state of individual refractory black carbon (rBC) particles in the south Asian outflow to Southeastern Arabian Sea, northern and equatorial Indian Ocean regions are presented based on measurements using a single particle soot photometer (SP2) aboard the ship cruise of the Integrated Campaign for Aerosols, gases, and Radiation Budget (ICARB-2018) during winter-2018 (16 January to 13 February). The results revealed significant spatial heterogeneity of BC characteristics. Highest rBC mass concentrations (~ 938 ± 293 ng m−3) with the highest relative coating thickness (RCT; the ratio of BC core to its coating diameters) of ~ 2.16 ± 0.19 are found over the Southeast Arabian Sea (SEAS) region, which is in the proximity of the continental outflow. As we move to farther oceanic regions, though the mass concentrations decreased by nearly half (~ 546 ± 80 ng m−3), BC still remained thickly coated (RCT ~ 2.05 ± 0.07). The air over the remote equatorial Indian Ocean, which received considerable marine air masses compared to the other regions, showed the lowest rBC mass concentrations (~ 206 ± 114 ng m−3), with a moderately thick coating (RCT ~ 1.73 ± 0.16). Even over oceanic regions far from the landmass, regions which received the outflow from more industrialized east coast/the Bay of Bengal had thicker coating (~ 104 nm) compared to regions that received outflow from the west coast/peninsular India (~ 86 nm). Although different regions of the ocean depicted contrasting concentrations and mixing state parameters due to varying extent and nature of the continental outflow as well as the atmospheric lifetime of air masses, the modal parameters of rBC mass-size distributions were similar over all the regions. The observed mono-modal distribution with mean mass median diameters (MMD) in the range of 0.19–0.20 μm suggested mixed sources of BC. The mean fraction of BC containing particles (FBC) varied in the range 0.20–0.28 (suggesting significant amounts of non-BC particles), whereas the bulk mixing ratio of coating mass to rBC mass was highest (8.77 ± 2.77) over the outflow regions compared to the remote ocean (4.29 ± 1.54) highlighting the role of outflow in providing condensable material for coating on rBC. These parameters, along with the information on size-resolved mixing state of BC cores, throw light on the role of sources and secondary processing of their complex mixtures for coating on BC under highly polluted conditions. Examination of the non-refractory sub-micrometre aerosol chemical composition obtained using the aerosol chemical speciation monitor (ACSM) suggested that the overall aerosol system was sulfate dominated over the far-oceanic regions. In contrast, organics were equally prominent adjacent to the coastal landmass. Association between the BC mixing state and aerosol chemical composition suggested that sulfate was the probable dominant coating material on rBC cores.

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