scholarly journals Evaluation of the impact of wood combustion on benzo(a)pyrene concentrations, using ambient air measurements and dispersion modelling in Helsinki, Finland

2016 ◽  
Author(s):  
Heidi Hellén ◽  
Leena Kangas ◽  
Anu Kousa ◽  
Mika Vestenius ◽  
Kimmo Teinilä ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Ambient Air ◽  
Local Source ◽  
Dispersion Modelling ◽  
Wood Combustion ◽  
Annual Average ◽  
Target Value ◽  
Detached House ◽  
Ambient Air Measurements ◽  
Helsinki Metropolitan Area

Abstract. Even though emission inventories indicate that wood combustion is a major source of PAHs, estimating its impacts on PAH concentration in ambient air is challenging. In this study effect of local small-scale wood combustion on the benzo(a)pyrene (BaP) concentrations in ambient air in the Helsinki metropolitan area in Finland was evaluated, using ambient air measurements, emission estimates and dispersion modelling. Measurements were conducted at 12 different locations during a period from 2007 to 2015. The spatial distributions of annual average benzo(a)pyrene concentrations originated from wood combustion were predicted for four years: 2008, 2011, 2013 and 2014. According to both the measurements and the dispersion modelling, the European Union target value for the annual average BaP concentrations (1 ng m−3) was clearly exceeded in part of the suburban detached house areas. However, over most of the other urban areas, including the centre of Helsinki, the concentrations were below the target value. The measured BaP concentrations were highly correlated with the measured levoglucosan concentrations at suburban detached house areas. In street canyons, the measured concentrations of BaP were at the same level as urban background, being clearly lower than those in suburban detached house areas. The predicted annual average concentrations agreed fairly well with the measured concentrations. Both measurements and modelling clearly indicated that wood combustion was the main local source of ambient air BaP in the Helsinki metropolitan area.

scholarly journals Evaluation of the impact of wood combustion on benzo[<i>a</i>]pyrene (BaP) concentrations; ambient measurements and dispersion modeling in Helsinki, Finland

2017 ◽  
Vol 17 (5) ◽  
pp. 3475-3487 ◽  
Author(s):  
Heidi Hellén ◽  
Leena Kangas ◽  
Anu Kousa ◽  
Mika Vestenius ◽  
Kimmo Teinilä ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Ambient Air ◽  
Local Source ◽  
Small Scale ◽  
Dispersion Modeling ◽  
Wood Combustion ◽  
Annual Average ◽  
Target Value ◽  
Detached House ◽  
Helsinki Metropolitan Area

Abstract. Even though emission inventories indicate that wood combustion is a major source of polycyclic aromatic hydrocarbons (PAHs), estimating its impacts on PAH concentration in ambient air remains challenging. In this study the effect of local small-scale wood combustion on the benzo[a]pyrene (BaP) concentrations in ambient air in the Helsinki metropolitan area in Finland is evaluated, using ambient air measurements, emission estimates, and dispersion modeling. The measurements were conducted at 12 different locations during the period from 2007 to 2015. The spatial distributions of annual average BaP concentrations originating from wood combustion were predicted for four of those years: 2008, 2011, 2013, and 2014. According to both the measurements and the dispersion modeling, the European Union target value for the annual average BaP concentrations (1 ng m−3) was clearly exceeded in certain suburban detached-house areas. However, in most of the other urban areas, including the center of Helsinki, the concentrations were below the target value. The measured BaP concentrations highly correlated with the measured levoglucosan concentrations in the suburban detached-house areas. In street canyons, the measured concentrations of BaP were at the same level as those in the urban background, clearly lower than those in suburban detached-house areas. The predicted annual average concentrations matched with the measured concentrations fairly well. Both the measurements and the modeling clearly indicated that wood combustion was the main local source of ambient air BaP in the Helsinki metropolitan area.

scholarly journals Spatiotemporal variation and trends of equivalent black carbon in the Helsinki metropolitan area in Finland

2020 ◽  
Author(s):  
Krista Luoma ◽  
Jarkko V. Niemi ◽  
Aku Helin ◽  
Minna Aurela ◽  
Hilkka Timonen ◽  
...  
Keyword(s):  
Time Series ◽  
Black Carbon ◽  
Metropolitan Area ◽  
Cold Season ◽  
Air Pollution Control ◽  
Wood Combustion ◽  
Urban Background ◽  
Regional Background ◽  
Different Types ◽  
Helsinki Metropolitan Area

Abstract. In this study, we present results of 12 years of black carbon (BC) measurements at 14 different measurement sites around the Helsinki metropolitan area (HMA) and at one background site outside the HMA. The main local sources of BC in the HMA are traffic, and residential wood combustion in fireplaces and sauna stoves. All the BC measurements were conducted optically and therefore we refer to the measured BC as equivalent BC (eBC). Measurement stations were located at different types of environments that represented traffic environment (six sites), detached housing area (five sites), urban background (two sites), and regional background (two sites). The measurements of eBC were conducted during 2007–2018; however, the time period and the length of the time series varied from site to site. As expected, the largest annual mean eBC concentrations were measured at the traffic sites (0.67–2.64 μg m−3) and the lowest at the regional background sites (0.16–0.29 μg m−3). The annual mean eBC concentrations at the detached housing sites varied in the range of 0.64–0.80 μg m−3 and the annual mean eBC concentrations at the urban background sites varied in the range of 0.42–0.68 μg m−3. The clearest seasonal variation was observed at the detached housing sites, where the residential wood combustion increased the eBC concentrations during the cold season. Traffic rates and wood burning influenced the diurnal and weekly variations of eBC concentration in different types of environments. The dependency was not so clear for the other air pollutants, which were here NOx and mass of particles smaller than 2.5 μm (PM2.5). At four sites, which had at least four-year-long time series available, we observed that the eBC concentrations had statistically significant decreasing trends, which varied in the range of −10.4–−5.9 % yr−1. Compared to the trends determined at the urban and regional background sites, the absolute trends decreased the fastest at the traffic sites and especially during the morning rush hour. The relative long-term trends of eBC and NOx were similar to each other, and their concentrations decreased more rapidly than the concentration of PM2.5. The results indicate that especially the emissions from traffic have decreased in the HMA during the last decade. This shows that air pollution control, new emission standards and newer fleet of vehicles really have an effect in the air quality.

scholarly journals Spatiotemporal variation and trends in equivalent black carbon in the Helsinki metropolitan area in Finland

2021 ◽  
Vol 21 (2) ◽  
pp. 1173-1189
Author(s):  
Krista Luoma ◽  
Jarkko V. Niemi ◽  
Minna Aurela ◽  
Pak Lun Fung ◽  
Aku Helin ◽  
...  
Keyword(s):  
Time Series ◽  
Air Quality ◽  
Black Carbon ◽  
Metropolitan Area ◽  
Air Pollution Control ◽  
Wood Combustion ◽  
Urban Background ◽  
Regional Background ◽  
Local Sources ◽  
Helsinki Metropolitan Area

Abstract. In this study, we present results from 12 years of black carbon (BC) measurements at 14 sites around the Helsinki metropolitan area (HMA) and at one background site outside the HMA. The main local sources of BC in the HMA are traffic and residential wood combustion in fireplaces and sauna stoves. All BC measurements were conducted optically, and therefore we refer to the measured BC as equivalent BC (eBC). Measurement stations were located in different environments that represented traffic environment, detached housing area, urban background, and regional background. The measurements of eBC were conducted from 2007 through 2018; however, the times and the lengths of the time series varied at each site. The largest annual mean eBC concentrations were measured at the traffic sites (from 0.67 to 2.64 µg m−3) and the lowest at the regional background sites (from 0.16 to 0.48 µg m−3). The annual mean eBC concentrations at the detached housing and urban background sites varied from 0.64 to 0.80 µg m−3 and from 0.42 to 0.68 µg m−3, respectively. The clearest seasonal variation was observed at the detached housing sites where residential wood combustion increased the eBC concentrations during the cold season. Diurnal variation in eBC concentration in different urban environments depended clearly on the local sources that were traffic and residential wood combustion. The dependency was not as clear for the typically measured air quality parameters, which were here NOx concentration and mass concentration of particles smaller that 2.5 µm in diameter (PM2.5). At four sites which had at least a 4-year-long time series available, the eBC concentrations had statistically significant decreasing trends that varied from −10.4 % yr−1 to −5.9 % yr−1. Compared to trends determined at urban and regional background sites, the absolute trends decreased fastest at traffic sites, especially during the morning rush hour. Relative long-term trends in eBC and NOx were similar, and their concentrations decreased more rapidly than that of PM2.5. The results indicated that especially emissions from traffic have decreased in the HMA during the last decade. This shows that air pollution control, new emission standards, and a newer fleet of vehicles had an effect on air quality.

scholarly journals The influence of residential wood combustion on the concentrations of PM<sub>2.5</sub> in four Nordic cities

2020 ◽  
Vol 20 (7) ◽  
pp. 4333-4365 ◽  
Author(s):  
Jaakko Kukkonen ◽  
Susana López-Aparicio ◽  
David Segersson ◽  
Camilla Geels ◽  
Leena Kangas ◽  
...  
Keyword(s):  
Air Quality ◽  
Atmospheric Dispersion ◽  
Ambient Air ◽  
City Centre ◽  
Wood Combustion ◽  
Annual Average ◽  
Suburban Areas ◽  
Extensive Evaluation ◽  
Urban Concentration ◽  
The City

Abstract. Residential wood combustion (RWC) is an important contributor to air quality in numerous regions worldwide. This study is the first extensive evaluation of the influence of RWC on ambient air quality in several Nordic cities. We have analysed the emissions and concentrations of PM2.5 in cities within four Nordic countries: in the metropolitan areas of Copenhagen, Oslo, and Helsinki and in the city of Umeå. We have evaluated the emissions for the relevant urban source categories and modelled atmospheric dispersion on regional and urban scales. The emission inventories for RWC were based on local surveys, the amount of wood combusted, combustion technologies and other relevant factors. The accuracy of the predicted concentrations was evaluated based on urban concentration measurements. The predicted annual average concentrations ranged spatially from 4 to 7 µg m−3 (2011), from 6 to 10 µg m−3 (2013), from 4 to more than 13 µg m−3 (2013) and from 9 to more than 13 µg m−3 (2014), in Umeå, Helsinki, Oslo and Copenhagen, respectively. The higher concentrations in Copenhagen were mainly caused by the relatively high regionally and continentally transported background contributions. The annual average fractions of PM2.5 concentrations attributed to RWC within the considered urban regions ranged spatially from 0 % to 15 %, from 0 % to 20 %, from 8 % to 22 % and from 0 % to 60 % in Helsinki, Copenhagen, Umeå and Oslo, respectively. In particular, the contributions of RWC in central Oslo were larger than 40 % as annual averages. In Oslo, wood combustion was used mainly for the heating of larger blocks of flats. In contrast, in Helsinki, RWC was solely used in smaller detached houses. In Copenhagen and Helsinki, the highest fractions occurred outside the city centre in the suburban areas. In Umeå, the highest fractions occurred both in the city centre and its surroundings.

scholarly journals Twelve-Year Trends of PM10and Visibility in the Hefei Metropolitan Area of China

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lin Huang ◽  
Mindong Chen ◽  
Jianlin Hu
Keyword(s):  
Air Quality ◽  
Metropolitan Area ◽  
Hot Spot ◽  
Ambient Air ◽  
Quality Standard ◽  
Capital City ◽  
Negative Effects ◽  
Annual Average ◽  
The Status ◽  
Second Tier

China has been experiencing severe air pollution and previous studies have mostly focused on megacities and a few hot spot regions. Hefei, the provincial capital city of Anhui province, has a population of near 5 million in its metropolitan area, but its air quality has not been reported in literature. In this study, daily PM10and visibility data in 2001–2012 were analyzed to investigate the air quality status as well as the twelve-year pollution trends in Hefei. The results reveal that Hefei has been suffering high PM10pollution and low visibility during the study period. The annual average PM10concentrations are 2~3 times of the Chinese Ambient Air Quality Standard. PM10shows fluctuating variation in 2001–2007 and has a slightly decreasing trend after 2008. The annual average visibility range is generally lower than 7 km and shows a worsening trend from 2001 to 2006 followed by an improving trend from 2007 to 2012. Wind speed, precipitation, and relative humidity have negative effects on PM10concentrations in Hefei, while temperature could positively or negatively affect PM10. The results provide a general understanding of the status and long-term trends of PM10pollution and visibility in a typical second-tier city in China.

scholarly journals The influence of residential wood combustion on the concentrations of PM<sub>2.5</sub> in four Nordic cities

2019 ◽  
Author(s):  
Jaakko Kukkonen ◽  
Susana López-Aparicio ◽  
David Segersson ◽  
Camilla Geels ◽  
Leena Kangas ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
Atmospheric Dispersion ◽  
Ambient Air ◽  
Nordic Countries ◽  
City Centre ◽  
Wood Combustion ◽  
Annual Average ◽  
Extensive Evaluation ◽  
The City

Abstract. Residential wood combustion (RWC) is an important contributor to air quality in numerous regions worldwide. This study is the first extensive evaluation of the influence of RWC on ambient air quality in several Nordic cities. We have analyzed the emissions and concentrations of PM2.5 in cities within four Nordic countries: the metropolitan areas of Copenhagen, Oslo and Helsinki, and Umeå. We have evaluated the emissions for the relevant urban source categories and modelled atmospheric dispersion on regional and urban scales. The emission inventories for RWC were based on local surveys, the amount of wood combusted, combustion technologies and other relevant factors. The accuracy of the predicted concentrations was evaluated based on urban concentration measurements. The predicted annual average concentrations ranged spatially from 4 to 7 μg/m3 (2011), from 6 to 10 μg/m3 (2013), from 4 to more than 13 μg/m3 (2013) and from 9 to more than 13 μg/m3 (2014), in Umeå, Helsinki, Oslo and Copenhagen, respectively. The higher concentrations in Copenhagen were mainly caused by the higher long-range transported background. The annual average fractions of PM2.5 concentrations attributed to RWC within the considered urban regions ranged spatially from 0 to 15 %, from 0 to 20 %, from 8 to 30 % and from 0 to 60 % in Helsinki, Copenhagen, Umeå and Oslo, respectively. In particular, the contributions of RWC in central Oslo were larger than 40 % as annual averages. In Oslo, wood combustion was used mainly for the heating of larger blocks of flats. On the contrary, in Helsinki, RWC was solely used in smaller detached houses. In Copenhagen and Helsinki, the highest fractions occurred outside the city center in the suburban areas. In Umeå, the highest fractions occurred both in the city centre and its surroundings. Stricter and more efficient emission regulations should be set in the Nordic countries with respect to RWC, especially in urban areas, for the protection of human health.

scholarly journals Refinement of a model for evaluating the population exposure in an urban area

2014 ◽  
Vol 7 (5) ◽  
pp. 1855-1872 ◽  
Author(s):  
J. Soares ◽  
A. Kousa ◽  
J. Kukkonen ◽  
L. Matilainen ◽  
L. Kangas ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Air Pollution ◽  
Urban Area ◽  
Metropolitan Area ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Population Exposure ◽  
Total Exposure ◽  
Helsinki Metropolitan Area ◽  
Modelling System

Abstract. A mathematical model is presented for the determination of human exposure to ambient air pollution in an urban area; the model is a refined version of a previously developed mathematical model EXPAND (EXposure model for Particulate matter And Nitrogen oxiDes). The model combines predicted concentrations, information on people's activities and location of the population to evaluate the spatial and temporal variation of average exposure of the urban population to ambient air pollution in different microenvironments. The revisions of the modelling system containing the EXPAND model include improvements of the associated urban emission and dispersion modelling system, an improved treatment of the time use of population, and better treatment for the infiltration coefficients from outdoor to indoor air. The revised model version can also be used for estimating intake fractions for various pollutants, source categories and population subgroups. We present numerical results on annual spatial concentration, time activity and population exposures to PM2.5 in the Helsinki Metropolitan Area and Helsinki for 2008 and 2009, respectively. Approximately 60% of the total exposure occurred at home, 17% at work, 4% in traffic and 19% in other microenvironments in the Helsinki Metropolitan Area. The population exposure originating from the long-range transported background concentrations was responsible for a major fraction, 86%, of the total exposure in Helsinki. The largest local contributors were vehicular emissions (12%) and shipping (2%).

scholarly journals The changing position of housing estate neighbourhoods in the Helsinki metropolitan area

2021 ◽  
Author(s):  
Johanna Lilius ◽  
Jukka Hirvonen
Keyword(s):  
Real Estate ◽  
Metropolitan Area ◽  
Social Geography ◽  
Housing Estate ◽  
Housing Investment ◽  
Private Households ◽  
Helsinki Metropolitan Area ◽  
1960S And 1970S ◽  
Rental Markets ◽  
The 1960S

AbstractThis paper addresses the under-researched phenomena of investments in the private rental markets in disadvantaged suburbs in Finland. Despite the application of a social-mixing policy in the Helsinki Metropolitan Area and the Nordic welfare model, suburban housing estate neighbourhoods built in the 1960s and 1970s have experienced a socioeconomic decline since the 1990s. According to several recent large surveys, housing estate neighbourhoods represent the least popular housing environments among Finns. Nevertheless, as the Helsinki Metropolitan Area is currently facing rapid population growth, these neighbourhoods have now become the target for heavy infill development, and ambitious city-led regeneration plans. Simultaneously, housing investment has become an opportunity in Finland for both national and, increasingly, also international real-estate investment companies, as well as for private households. We explore the resurge to invest in housing estate neighbourhoods through two case studies in the Helsinki Metropolitan Area. Using statistics and interviews with policymakers and institutional real-estate investors, as well as a review of policy documents as our data, we show the variegated ways in which the marketization and financialization of housing and urban renewal policies change the social geography of housing estates in the Helsinki Metropolitan Area.

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