scholarly journals An integrated assessment of the impacts of PM2.5 and black carbon particles on the air quality of a large Brazilian city

2021 ◽  
Author(s):  
Lars Gidhagen ◽  
Patricia Krecl ◽  
Admir Créso Targino ◽  
Gabriela Polezer ◽  
Ricardo H. M. Godoi ◽  
...  
Keyword(s):  
Air Quality ◽  
Black Carbon ◽  
Dispersion Model ◽  
Open Data ◽  
Integrated Approach ◽  
Biomass Combustion ◽  
Dispersion Modeling ◽  
Urban Background ◽  
In Situ Data ◽  
The City

AbstractData on airborne fine particle (PM2.5) emissions and concentrations in cities are valuable for traffic and air quality managers, urban planners, health practitioners, researchers, and ultimately for legislators and decision makers. Emissions and ambient concentrations of PM2.5 and black carbon (BC) were assessed in the city of Curitiba, southern Brazil. The methodology combined a month-long monitoring campaign with both fixed and mobile instruments, development of emission inventories, and dispersion model simulations on different scales. The mean urban background PM2.5 concentrations during the campaign were 7.3 μg m−3 in Curitiba city center, but three- to fourfold higher (25.3 μg m-3) in a residential area on the city’s outskirts, indicating the presence of local sources, possibly linked to biomass combustion. BC concentrations seemed to be more uniformly distributed over the city, with mean urban background concentrations around 2 μg m−3, half of which due to local traffic emissions. Higher mean BC concentrations (3–5 μg m-3) were found along busy roads. The dispersion modeling also showed high PM2.5 and BC concentrations along the heavily transited ring road. However, the lack of in situ data over these peripheral areas prevented the verification of the model output. The vehicular emission factors for PM2.5 and BC from the literature were found not to be suitable for Curitiba’s fleet and needed to be adjusted. The integrated approach of this study can be implemented in other cities, as long as an open data policy and a close cooperation among regional, municipal authorities and academia can be achieved.

scholarly journals Experimental and model assessment of PM<sub>2.5</sub> and BC emissions and concentrations in a Brazilian city – the Curitiba case study

2018 ◽  
Author(s):  
Lars Gidhagen ◽  
Patricia Krecl ◽  
Admir Créso Targino ◽  
Gabriela Polezer ◽  
Ricardo H. M. Godoi ◽  
...  
Keyword(s):  
Fine Particles ◽  
Open Data ◽  
Integrated Approach ◽  
Industrial Area ◽  
Dispersion Modeling ◽  
Model Assessment ◽  
Wood Combustion ◽  
Urban Background ◽  
In Situ Data ◽  
The City

Abstract. Data on airborne fine particle emissions and concentrations in cities are valuable to traffic and air quality managers, urban planners and landscape architects, health practitioners, researchers, and ultimately to legislators and decision makers. This study aimed at determining the emissions and ambient concentrations of black carbon (BC) and fine particles (PM2.5) in the city of Curitiba, southern Brazil. The methodology applied combined a month-long monitoring campaign that included both fixed and mobile instruments, the development of emission inventories, and the dispersion simulation from the regional down to the street scale. The mean urban background PM2.5 concentrations during the campaign were below 10 µg m−3 in Curitiba city center, but two- to three-fold higher in a residential area, indicating the presence of unidentified local sources, possibly linked to wood combustion. Mean BC concentrations seemed to be more uniformly distributed over the city, with urban background levels around 2 µg m−3, which rose to about 5 µg m−3 in heavily trafficked street canyons. The dispersion modeling also showed high PM2.5 and BC concentrations along the heavily transited ring road and over the industrial area southwest of Curitiba. However, the lack of in situ data over this area prevented the corroboration of the model outputs. The integrated approach used in this study can be implemented in other Brazilian cities as long as an open data policy and a close cooperation between municipal authorities and academia can be achieved.

scholarly journals Development of the city-scale chemistry transport model CityChem-EPISODE and its application to the city of Hamburg

2018 ◽  
Author(s):  
Matthias Karl
Keyword(s):  
Air Quality ◽  
Urban Area ◽  
Transport Model ◽  
Dispersion Model ◽  
Temporal Correlation ◽  
Urban Atmosphere ◽  
Aerosol Formation ◽  
Urban Background ◽  
New Model ◽  
The City

Abstract. This paper describes the City-scale Chemistry (CityChem) extension of the urban dispersion model EPISODE with the aim to enable chemistry/transport simulations of multiple reactive pollutants on urban scales. The new model is called CityChem-EPISODE. The primary focus is on the simulation of urban ozone concentrations. Ozone is produced in photochemical reaction cycles involving nitrogen oxides (NOx) and volatile organic compounds (VOC) emitted by various anthropogenic activities in the urban area. The performance of the new model was evaluated with a series of synthetic tests and with a first application to the air quality situation in the city of Hamburg, Germany. The model performs fairly well for ozone in terms of temporal correlation and bias at the air quality monitoring stations in Hamburg. In summer afternoons, when photochemical activity is highest, modelled median ozone at an inner-city urban background station was about 30 % lower than the observed median ozone. Inaccuracy of the computed photolysis frequency of nitrogen dioxide (NO2) is the most probable explanation for this. CityChem-EPISODE reproduces the spatial variation of annual mean NO2 concentrations between urban background, traffic and industrial stations. However, the temporal correlation between modelled and observed hourly NO2 concentrations is weak for some of the stations. For daily mean PM10, the performance of CityChem-EPISODE is moderate due to low temporal correlation. The low correlation is linked to uncertainties in the seasonal cycle of the anthropogenic particulate matter (PM) emissions within the urban area. Missing emissions from domestic heating might be an explanation for the too low modelled PM10 in winter months. Four areas of need for improvement have been identified: (1) dry and wet deposition fluxes; (2) treatment of photochemistry in the urban atmosphere; (3) formation of secondary inorganic aerosol (SIA); and (4) formation of biogenic and anthropogenic secondary organic aerosol (SOA). The inclusion of secondary aerosol formation will allow for a better sectorial attribution of observed PM levels. Envisaged applications of the CityChem-EPISODE model are urban air quality studies, environmental impact assessment, sensitivity analysis of sector-specific emission and the assessment of local and regional emission abatement policy options.

scholarly journals GEOSTATISTICS FOR AIR QUALITY MAPPING: CASE OF BAGUIO CITY, PHILIPPINES

2019 ◽  
Vol XLII-4/W19 ◽  
pp. 353-359
Author(s):  
R. V. Ramos ◽  
A. C. Blanco
Keyword(s):  
Air Quality ◽  
Dispersion Model ◽  
Atmospheric Dispersion ◽  
Spatial Variations ◽  
Dispersion Modeling ◽  
Dispersion Models ◽  
Night Time ◽  
Smoothing Factor ◽  
Pollutant Concentrations ◽  
Atmospheric Dispersion Models

Abstract. Mapping of air quality are often based on ground measurements using gravimetric and air portable sensors, remote sensing methods and atmospheric dispersion models. In this study, Geographic Information Systems (GIS) and geostatistical techniques are employed to evaluate coarse particulate matter (PM10) concentrations observed in the Central Business District of Baguio City, Philippines. Baguio City has been reported as one of the most polluted cities in the country and several studies have already been conducted in monitoring its air quality. The datasets utilized in this study are based on hourly simulations from a Gaussian-based atmospheric dispersion model that considers the impacts of vehicular emissions. Dispersion modeling results, i.e., PM10 concentrations at 20-meter interval, show that high values range from 135 to 422 μg/mm3. The pollutant concentrations are evident within 40 meters from the roads. Spatial variations and PM10 estimates at unsampled locations are determined using Ordinary Kriging. Geostatistical modeling estimates are evaluated based on recommended values for mean error (ME), root mean square error (RMSE) and standardized errors. Optimal predictors for pollutant concentrations at 5-meter interval include 2 to 5 search neighbors and variable smoothing factor for night-time datasets while 2 to 10 search neighbors and smoothing factors 0.3 to 0.5 were used for daytime datasets. Results from several interpolation tests indicate small ME (0.0003 to 0.0008 μg/m3) and average standardized errors (4.24 to 8.67 μg/m3). RMSE ranged from 2.95 to 5.43 μg/m3, which are approximately 2 to 3% of the maximum pollutant concentrations in the area. The methodology presented in this paper may be integrated with atmospheric dispersion models in refining estimates of pollutant concentrations, in generating surface representations, and in understanding the spatial variations of the outputs from the model simulations.

scholarly journals On the application and grid-size sensitivity of the urban dispersion model CAIRDIO for the simulation of a real city and realistic meteorology

2021 ◽  
Author(s):  
Michael Weger ◽  
Bernd Heinold ◽  
Alfred Wiedensohler ◽  
Maik Merkel
Keyword(s):  
Air Quality ◽  
Dispersion Model ◽  
Gray Zone ◽  
Grid Spacing ◽  
Mesoscale Simulation ◽  
Urban Dispersion ◽  
Street Canyons ◽  
Urban Background ◽  
Diurnal Variability ◽  
Horizontal Grid

Abstract. There is a gap between the need for city-wide air-quality simulations considering the intra-urban variability and mircoscale dispersion features and the computational capacities that conventional urban microscale models require. This gap can be bridged by targeting model applications on the gray zone situated between the mesoscale and large-eddy scale. The urban dispersion model CAIRDIO is a new contribution to the class of computational-fluid dynamics models operating in this scale range. It uses a diffuse-obstacle boundary method to represent buildings as physical obstacles at gray-zone resolutions in the order of tens of meters. The main objective of this approach is to find an acceptable compromise between computationally inexpensive grid sizes for spatially comprehensive applications and the required accuracy in the description of building and boundary-layer effects. For this purpose, CAIRDIO is applied in dispersion simulation of black carbon and particulate matter for an entire mid-size city using an uniform horizontal resolution of 40 m in this paper. For evaluation, the simulation results are compared with measurements from 5 operational air monitoring stations, which are representative for the urban background and high-traffic roads, respectively. Moreover, the comparison includes the mesoscale host simulation, which provides the boundary conditions. The temporal variability of the concentration measurements at the background sites was largely influenced only by the characteristics of the mixing layer. As a consequence, the model results were not significantly dependent on spatial resolution, so that the mesoscale simulation also performed reasonably well. At the traffic sites, however, concentrations were in addition markedly influenced by the proximity to road-traffic sources and the surrounding building environment. Here, the mesoscale simulation indiscriminately reproduced almost the same urban-background profiles, which resulted in a large positive model bias. On the other hand, the CAIRDIO simulation was able to respond to the significantly amplified diurnal variability with its pronounced rush-hour peaks. This resulted in a consistent improvement of the model deviation to mea- surements compared to the mesoscale simulation. Nevertheless, discrepancies to measurements remain in the 40 m-CAIRDIO simulation, e.g., an underestimation of peak concentrations at two traffic sites inside narrow street canyons. To further research resolution sensitivity, the horizontal grid spacing of locally nested CAIRDIO domains is refined down to 5 m. While for the street canyons the representation of peak concentrations can be improved using horizontal grid spacings of up to 10 m, no further improvements beyond this resolution can be observed. This suggests that the too low peak concentrations with the default grid spacing of 40 m result from an inadequate representation of the traffic emissions inside narrow street canyons. If the total gain in accuracy due to the grid refinements is put in relation to the remaining model error, the improvements are only modest. In conclusion, the proposed gray-scale modeling is a promising downscaling approach for urban air-quality applications. Nevertheless, the results also show that aspects other than the actual resolution of flow patterns and numerical effects can determine the simulations at the urban microscale.

scholarly journals The Eulerian urban dispersion model EPISODE. Part II: Extensions to the source dispersion and photochemistry for EPISODE-CityChem v1.2 and its application to the city of Hamburg

2019 ◽  
Author(s):  
Matthias Karl ◽  
Sam-Erik Walker ◽  
Sverre Solberg ◽  
Martin O. P. Ramacher
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Dispersion Model ◽  
Model Performance ◽  
Pollutant Dispersion ◽  
Lower Latitude ◽  
Urban Dispersion ◽  
Grid Model ◽  
The City

Abstract. This paper describes the CityChem extension of the Eulerian urban dispersion model EPISODE. The development of the CityChem extension was driven by the need to apply the model in lower latitude cities with higher insolation than in northern European cities. The CityChem extension offers a more advanced treatment of the photochemistry in urban areas and entails specific developments within the sub-grid components for a more accurate representation of the dispersion in the proximity of urban emission sources. The WMPP (WORM Meteorological Pre-Processor) is used in the point source sub-grid model to calculate the wind speed at plume height. The simplified street canyon model (SSCM) is used in the line source sub-grid model to calculate pollutant dispersion in street canyons. The EPISODE-CityChem model integrates the CityChem extension in EPISODE, with the capability of simulating photochemistry and dispersion of multiple reactive pollutants within urban areas. The main focus of the model is the simulation of the complex atmospheric chemistry involved in the photochemical production of ozone in urban areas. EPISODE-CityChem was evaluated with a series of tests and with a first application to the air quality situation in the city of Hamburg, Germany. A performance analysis with the FAIRMODE DELTA Tool for the air quality in Hamburg showed that the model fulfils the model performance objectives for NO2 (hourly), O3 (daily max. of the 8-h running mean) and PM10 (daily mean) set forth in the Air Quality Directive, qualifying the model for use in policy applications. Observed levels of annual mean ozone at the five urban background stations in Hamburg are captured by the model within 15 %. Envisaged applications of the EPISODE-CityChem model are urban air quality studies, emission control scenarios in relation to traffic restrictions and the source attribution of sector-specific emissions to observed levels of air pollutants at urban monitoring stations.

scholarly journals High Contribution of Biomass Combustion to PM2.5 in the City Centre of Naples (Italy)

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 451 ◽  
Author(s):  
Carmina Sirignano ◽  
Angelo Riccio ◽  
Elena Chianese ◽  
Haiyan Ni ◽  
Katrin Zenker ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Fossil Fuel ◽  
Total Carbon ◽  
Carbonaceous Aerosol ◽  
City Centre ◽  
Biomass Combustion ◽  
Policy Makers ◽  
The City ◽  
Fossil Fuel Emissions

A better knowledge of the local and regional sources of the atmospheric particulate matter provides policy makers with the proper awareness when acting to improve air quality, in order to protect public health. A source apportionment study of the carbonaceous aerosol in Naples (Italy) is presented here, in order to improve this understanding in a vulnerable urban area. The aim of this study is quantifying directly fossil and non-fossil contributions to carbonaceous aerosol, by means of radiocarbon measurements. This is the first time that such an approach is implemented in this area. Fine particles with diameter ≤ 2.5 µm (PM2.5) were collected daily on top of a building in the city center, from November 2016 until January 2017. The carbonaceous aerosol was separated into organic carbon (OC) and elemental carbon (EC), by a two-step thermal desorption method. Subsequent radiocarbon analysis enabled the partitioning of the major sources of carbonaceous aerosol into fossil and non-fossil ones by applying radiocarbon isotopic mass balance. The PM2.5 concentration was on average 29 ± 3 µg⁄m3 (mean ± standard error; n = 18), with a maximum of 68.6 ± 0.7 µg⁄m3 on a day when air masses back-trajectories suggest a local origin and stagnant airflow conditions in the region. The carbonaceous component accounts for roughly half of the PM2.5 mass. Fossil fuel emissions are a minor source of OC (23%), but the dominant source of EC (66%), which is directly emitted during combustion processes. However, overall only 30% of the total carbon is of fossil origin, accounting for 14% of PM2.5 mass. Surprisingly, a comparable contribution is due to primary biomass burning carbon, which accounts in total for 15% of PM2.5 mass. Traffic pollution, the main cause of fossil fuel emissions in urban areas, is a significant, but not the predominant source of carbonaceous particle concentration. These findings support the conclusion of a predominant contribution from non-fossil sources to the carbon in airborne particulate matter, which policy makers should take into account when planning mitigation strategies to improve urban air quality.

scholarly journals Comparison of measured residential black carbon levels outdoors and indoors with fixed-site monitoring data and with dispersion modelling

2020 ◽  
Author(s):  
Olena Gruzieva ◽  
Antonios Georgelis ◽  
Niklas Andersson ◽  
Tom Bellander ◽  
Christer Johansson ◽  
...  
Keyword(s):  
Time Series ◽  
Black Carbon ◽  
Health Effects ◽  
Dispersion Model ◽  
Monitoring Data ◽  
Dispersion Modelling ◽  
Night Time ◽  
Urban Background ◽  
Site Monitoring

AbstractEpidemiologic studies on health effects of air pollution usually rely on time-series of ambient monitoring data or on spatially modelled levels. Little is known how well these estimate residential outdoor and indoor levels. We investigated the agreement of measured residential black carbon (BC) levels outdoors and indoors with fixed-site monitoring data and with levels calculated using a Gaussian dispersion model. One-week residential outdoor and indoor BC measurements were conducted for 15 families living in central Stockholm. Time-series from urban background and street-level monitors were compared to these measurements. The observed weekly concentrations were also standardized to reflect annual averages, using urban background levels, and compared spatially to long-term levels as estimated by dispersion modelling. Weekly average outdoor BC level was 472 ng/m3 (range 261–797 ng/m3). The corresponding fixed-site urban background and street levels were 313 and 1039 ng/m3, respectively. Urban background variation explained 50% of the temporal variation in residential outdoor levels averaged over 24 h. Modelled residential long-term outdoor levels were on average comparable with the standardized measured home outdoor levels, and explained 49% of the spatial variability. The median indoor/outdoor ratio across all addresses was 0.79, with no difference between day and night time. Common exposure estimation approaches in the epidemiology of health effects related to BC displayed high validity for residencies in central Stockholm. Urban background monitored levels explained half of the outdoor day-to-day variability at residential addresses. Long-term dispersion modelling explained half of the spatial differences in outdoor levels. Indoor BC concentrations tended to be somewhat lower than outdoor levels.

scholarly journals Input-Adaptive Proxy for Black Carbon as a Virtual Sensor

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 182 ◽  
Author(s):  
Pak Lun Fung ◽  
Martha A. Zaidan ◽  
Salla Sillanpää ◽  
Anu Kousa ◽  
Jarkko V. Niemi ◽  
...  
Keyword(s):  
Air Quality ◽  
Missing Data ◽  
Black Carbon ◽  
Street Canyon ◽  
Ordinary Least Squares ◽  
Coefficient Of Determination ◽  
Data Set ◽  
Virtual Sensor ◽  
Urban Background ◽  
Input Variables

Missing data has been a challenge in air quality measurement. In this study, we develop an input-adaptive proxy, which selects input variables of other air quality variables based on their correlation coefficients with the output variable. The proxy uses ordinary least squares regression model with robust optimization and limits the input variables to a maximum of three to avoid overfitting. The adaptive proxy learns from the data set and generates the best model evaluated by adjusted coefficient of determination (adjR2). In case of missing data in the input variables, the proposed adaptive proxy then uses the second-best model until all the missing data gaps are filled up. We estimated black carbon (BC) concentration by using the input-adaptive proxy in two sites in Helsinki, which respectively represent street canyon and urban background scenario, as a case study. Accumulation mode, traffic counts, nitrogen dioxide and lung deposited surface area are found as input variables in models with the top rank. In contrast to traditional proxy, which gives 20–80% of data, the input-adaptive proxy manages to give full continuous BC estimation. The newly developed adaptive proxy also gives generally accurate BC (street canyon: adjR2 = 0.86–0.94; urban background: adjR2 = 0.74–0.91) depending on different seasons and day of the week. Due to its flexibility and reliability, the adaptive proxy can be further extend to estimate other air quality parameters. It can also act as an air quality virtual sensor in support with on-site measurements in the future.

scholarly journals Comparison of measurements of peroxyacyl nitrates and primary carbonaceous aerosol concentrations in Mexico City determined in 1997 and 2003

2007 ◽  
Vol 7 (9) ◽  
pp. 2277-2285 ◽  
Author(s):  
N. A. Marley ◽  
J. S. Gaffney ◽  
R. Ramos-Villegas ◽  
B. Cárdenas González
Keyword(s):  
Air Quality ◽  
Black Carbon ◽  
Mexico City ◽  
Elemental Carbon ◽  
Control Strategies ◽  
Ambient Air ◽  
Daily Maximum ◽  
Atmospheric Measurements ◽  
Important Species ◽  
The City

Abstract. The concentrations of peroxyacetyl nitrate (PAN) in ambient air can be a good indicator of air quality and the effectiveness of control strategies for reducing ozone levels in urban areas. As PAN is formed by the oxidation of reactive hydrocarbons in the presence of nitrogen dioxide (NO2), it is a direct measure of the peroxyacyl radical levels produced from reactive organic emissions in the urban air shed. Carbon soot, known as black carbon (BC) or elemental carbon (EC), is a primary atmospheric aerosol species and is a good indicator of the levels of combustion emissions, particularly from diesel engines, in major cities. Mexico City is the second largest megacity in the world and has long suffered from poor air quality. Reported here are atmospheric measurements of PAN and BC obtained in Mexico City during the Mexico Megacity 2003 field study. These results are compared with measurements obtained earlier during the Investigación sobre Materia Particulada y Deterioro Atmosférico – Aerosol and Visibility Research (IMADA-AVER) campaign in 1997 to obtain an estimate of the changes in emissions in Mexico City and the effectiveness of control strategies adopted during that time. Concentrations of PAN in 1997 reached a maximum of 34 ppb with an average daily maximum of 15 ppb. The PAN levels recorded in 2003 were quite different, with an average daily maximum of 3 ppb. This dramatic reduction in PAN levels observed in 2003 indicate that reactive hydrocarbon emissions have been reduced in the city due to controls on olefins in liquefied petroleum gas (LPG) and also due to the significant number of newer vehicles with catalytic converters that have replaced older higher emission vehicles. In contrast, black/elemental carbon levels were similar in 1997 and 2003 indicating little improvement likely due to the lack of controls on diesel vehicles in the city. Thus, while air quality and ozone production have improved, Mexico City and other megacities continue to be a major source of black carbon aerosols, which can be an important species in determining regional radiative balance and climate.

scholarly journals Comparison of measurements of peroxyacyl nitrates and primary carbonaceous aerosol concentrations in Mexico City determined in 1997 and 2003

2007 ◽  
Vol 7 (1) ◽  
pp. 1421-1448 ◽  
Author(s):  
N. A. Marley ◽  
J. S. Gaffney ◽  
R. Ramos-Villegas ◽  
B. Cárdenas González
Keyword(s):  
Air Quality ◽  
Black Carbon ◽  
Mexico City ◽  
Elemental Carbon ◽  
Control Strategies ◽  
Ambient Air ◽  
Daily Maximum ◽  
Atmospheric Measurements ◽  
Important Species ◽  
The City

Abstract. Peroxyacetyl nitrate (PAN) concentrations in ambient air can be a good indicator of air quality and the effectiveness of control strategies for reducing ozone levels in urban areas. As PAN is formed by the oxidation of reactive hydrocarbons in the presence of nitrogen dioxide (NO2), it is a direct measure of the peroxyacyl radical levels produced from reactive organic emissions in the urban air shed. Carbon soot, known as black carbon or elemental carbon, is a primary atmospheric aerosol species and is a good indicator of the levels of combustion emissions, particularly from diesel engines, in major cities. Mexico City is the second largest megacity in the world and has long suffered from poor air quality. Reported here are atmospheric measurements of PAN and black carbon obtained in Mexico City during the Mexico Megacity 2003 field study. These results are compared with measurements obtained earlier during the Investigación sobre Materia Particulada y Deterioro Atmosférico – Aerosol and Visibility Research (IMADA-AVER) campaign in 1997 to obtain an estimate of the changes in emissions in Mexico City and the effectiveness of control strategies adopted during that time. Concentrations of PAN in 1997 reached a maximum of 34 ppb with an average daily maximum of 15 ppb. The PAN levels recorded in 2003 were quite different, with an average daily maximum of 3 ppb. This dramatic reduction in PAN levels observed in 2003 indicate that reactive hydrocarbon emissions have been reduced in the city due to controls on olefins in liquefied petroleum gas (LPG) and also due to the significant number of newer vehicles with catalytic converters that have replaced older higher emission vehicles. In contrast, black/elemental carbon levels were similar in 1997 and 2003 indicating little improvement likely due to the lack of controls on diesel vehicles in the city. Thus, while air quality and ozone production has improved, Mexico City and other megacities continue to be a major source of black carbon aerosols, which can be an important species in determining regional radiative balance and climate.

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