TY - JOUR
T1 - Characterization of particle sources and comparison of different particle metrics in an urban detached housing area, Finland
AU - Teinilä, K.
AU - Timonen, H.
AU - Aurela, M.
AU - Kuula, J.
AU - Rönkkö, T.
AU - Hellèn, H.
AU - Loukkola, K.
AU - Kousa, A.
AU - Niemi, J. V.
AU - Saarikoski, S.
N1 - Funding Information:
Long-term research co-operation and support from HSY to this project is gratefully acknowledged. Financial support from Black Carbon Footprint project funded by Business Finland and participating companies (Grant 528/31/2019 ), from European Regional Development Fund , Urban innovative actions initiative (HOPE; Healthy Outdoor Premises for Everyone, project nro: UIA03-240 ), from MegaSense Growth Engine : Air Quality Monitoring funded by Business Finland (Grant 7517/31/2018 ) and Academy of Finland Flagship ACCC (grant no. 337552 , 337551 ) are gratefully acknowledged.
Funding Information:
The aim of this study is to characterize the sources affecting air quality in an urban detached housing area, Finland, and identify the additional parameters that needs to be measured in order to characterize better the impact of these sources on air quality. Special attention is paid on the parameters that can be monitored in real-time in the air quality monitoring networks i.e., particle number, LDSA and BC concentrations. To support the characterization of the sources, Soot Particle Aerosol Mass Spectrometer (SP-AMS) measurements were carried out at the site and the data was analysed with a Positive Matrix Factorization (PMF) method. Additionally, daily PM10 filter samples were analysed for biomass burning markers, monosaccharide anhydrides (MAs), as well as for PAHs. Earlier studies in the Helsinki metropolitan area (e.g., Kuula et al., 2020a; Luoma et al., 2021; Pirjola et al., 2017; Aurela et al., 2015) have found differences between the sources, concentrations and chemical composition of particulate matter at the sites which represent different urban environments. In this study, we focus on the detailed characterization of particle physical and chemical properties and sources by using the real time instruments as well as PM10 filter samples. This information will be further utilized to explore the monitoring parameters needed to be measured in order to assess the impact of these sources on air quality. The results presented in this study are necessary for the authorities when assessing the climate and air quality impacts of anthropogenic particulate sources as well as directing the emission legislation and emission mitigation actions. Although the measurements were performed only at one location in Helsinki, Finland, the results are also applicable to other similar areas.Mean PM1 concentration was the lowest during the period representing urban background aerosol. When strong local or LRT sources are missing, the measurement site was mostly affected by regionally dispersed traffic and biomass combustion related pollutants. The relatively low concentrations of PN, NOx and BC during the morning rush hours (Fig. S10) indicated that the influence of local traffic was minimal, although they had similar diurnal profiles as during the whole campaign with a clear morning peak. As the urban background period was in March, the mixing height was greater than in wintertime and the additional dilution of relatively low concentrations of traffic related pollutants probably prevented the detection of the afternoon rush hour peak clearly. In contrast to these, BC showed high concentrations in late evening, which indicated that it was not only connected to traffic related emissions but also to residential wood burning. Although the BC concentration from local wood burning in the late evening was small, its contribution to the total BC concentration was larger than the contribution of traffic related morning BC. Wood burning is likely to have some contribution to BC concentrations throughout the year at the measurement site since many of the detached houses are typically equipped with wood-fired sauna stoves which are used around the year. Also, the mass size distribution of rBC (Fig. 3) supported the influence of wood burning emissions as it had a maximum at a rather large particle size (?500 nm), but we note that a large fraction of BC can also be originating from LRT in Helsinki (Niemi et al., 2009; Luoma et al., 2021). Traffic related fresh BC is typically seen at ?100 nm (Enroth et al., 2016). The fraction of BC in PM1 was 11% (Fig. 4) which was similar to the BC fraction measured in the heavily traffic influenced Helsinki city centre (Teinil? et al., 2019), although the absolute concentration of BC was much less at the detached house measurement site.The concentration of BC was also elevated during the LRT period (Table 1, Fig. 1), and its origin is most likely LRT biomass burning, but it may also partly explain by traffic related emission. All motor vehicle emission indicators, BC, NOx, HOA and PN, showed a clear morning peak during the LRT period (Fig. S13), and the increase in their concentrations in the morning was much larger than during urban background or wood burning periods indicating a strong influence of local or regional traffic related pollutants. However, their concentration throughout the day was also clearly higher, which may indicate that they were also partly long-range transported to the measurement site. In terms of size-distributions, all chemical species had a maximum at ?400?450 nm except rBC that peaked at slightly smaller size at ?350?400 nm. This also supports the finding that BC originated partly from traffic emissions, whereas the other species were mostly internally mixed during the transport.Long-term research co-operation and support from HSY to this project is gratefully acknowledged. Financial support from Black Carbon Footprint project funded by Business Finland and participating companies (Grant 528/31/2019), from European Regional Development Fund, Urban innovative actions initiative (HOPE; Healthy Outdoor Premises for Everyone, project nro: UIA03-240), from MegaSense Growth Engine: Air Quality Monitoring funded by Business Finland (Grant 7517/31/2018) and Academy of Finland Flagship ACCC (grant no. 337552, 337551) are gratefully acknowledged.
Publisher Copyright:
© 2022 The Authors
PY - 2022/3/1
Y1 - 2022/3/1
N2 - Particulate matter (PM) is emitted from various anthropogenic sources in urban areas affecting the local air quality. The aim of this study was to characterize the sources influencing air quality in detached house area in the Helsinki metropolitan area in Finland, and secondly, to explore the additional value of new particle physical properties to assess the impact of residential combustion on air quality. Measurements were conducted in an urban detached housing area between January and April 2019. Measured particle physical properties were particle number (PN), particle mass (PM1) and lung deposited surface area (LDSA) concentrations and number size distributions. In addition, particle chemical composition was measured using a soot particle aerosol mass spectrometer (SP-AMS; organic compounds, inorganic ions) and an aethalometer (black carbon (BC)). Concentrations of selected monosaccharide anhydrides and polycyclic aromatic hydrocarbons were analysed from the PM10 filter samples. The sources and characteristics of organic aerosol was investigated by applying positive matrix factorization to the mass spectra measured with the SP-AMS. Based on the variations in the measured particle physical parameters, chemical species and meteorology, the measurement period was divided into three sub periods dominated by urban background, wood burning and long-range transport (LRT) aerosols. Highest pollutant concentrations were measured during the wood burning and LRT periods. Wood burning increased the concentrations of all measured species, but the differences were most significant to levoglucosan, benzo(a)pyrene, BC and PM1 that had 12, 10, 6.4 and 3.6 times larger mean concentrations during the wood burning period compared to the urban background period, respectively. LRT affected significantly levoglucosan, PM1 and BC concentrations, since LRT pollutants partly originated from open biomass fires in Eastern Europe. The impact of local wood burning and LRT was quite small to particle number concentrations, whereas LDSA concentrations and size distributions were affected by traffic, wood combustion emissions and LRT. BC concentration correlated with the LDSA concentration during all periods suggesting a common origin. Particle number concentration was a good indicator of local combustion, especially traffic emissions, while the PM1 mass concentration together with secondary particle material was a good measure for the LRT pollutants. Benzo(a)pyrene was found to be a good indicator of local wood burning, but it was not detected in LRT biomass combustion particles.
AB - Particulate matter (PM) is emitted from various anthropogenic sources in urban areas affecting the local air quality. The aim of this study was to characterize the sources influencing air quality in detached house area in the Helsinki metropolitan area in Finland, and secondly, to explore the additional value of new particle physical properties to assess the impact of residential combustion on air quality. Measurements were conducted in an urban detached housing area between January and April 2019. Measured particle physical properties were particle number (PN), particle mass (PM1) and lung deposited surface area (LDSA) concentrations and number size distributions. In addition, particle chemical composition was measured using a soot particle aerosol mass spectrometer (SP-AMS; organic compounds, inorganic ions) and an aethalometer (black carbon (BC)). Concentrations of selected monosaccharide anhydrides and polycyclic aromatic hydrocarbons were analysed from the PM10 filter samples. The sources and characteristics of organic aerosol was investigated by applying positive matrix factorization to the mass spectra measured with the SP-AMS. Based on the variations in the measured particle physical parameters, chemical species and meteorology, the measurement period was divided into three sub periods dominated by urban background, wood burning and long-range transport (LRT) aerosols. Highest pollutant concentrations were measured during the wood burning and LRT periods. Wood burning increased the concentrations of all measured species, but the differences were most significant to levoglucosan, benzo(a)pyrene, BC and PM1 that had 12, 10, 6.4 and 3.6 times larger mean concentrations during the wood burning period compared to the urban background period, respectively. LRT affected significantly levoglucosan, PM1 and BC concentrations, since LRT pollutants partly originated from open biomass fires in Eastern Europe. The impact of local wood burning and LRT was quite small to particle number concentrations, whereas LDSA concentrations and size distributions were affected by traffic, wood combustion emissions and LRT. BC concentration correlated with the LDSA concentration during all periods suggesting a common origin. Particle number concentration was a good indicator of local combustion, especially traffic emissions, while the PM1 mass concentration together with secondary particle material was a good measure for the LRT pollutants. Benzo(a)pyrene was found to be a good indicator of local wood burning, but it was not detected in LRT biomass combustion particles.
KW - Aerosol chemical composition
KW - Long-range transport
KW - Particulate matter
KW - Traffic
KW - wood burning
U2 - 10.1016/j.atmosenv.2022.118939
DO - 10.1016/j.atmosenv.2022.118939
M3 - Article
AN - SCOPUS:85122961986
SN - 1352-2310
VL - 272
JO - Atmospheric Environment
JF - Atmospheric Environment
M1 - 118939
ER -
