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

doi:10.5194/acp-2020-201

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-201
	Spatiotemporal variation and trends of equivalent black carbon in the Helsinki metropolitan area in Finland
	Krista Luoma, Jarkko V. Niemi, Aku Helin, Minna Aurela, Hilkka Timonen, Aki Virkkula, Topi Rönkkö, Anu Kousa, Pak Lun Fung, Tareq Hussein, and Tuukka Petäjä
	2020-04-29
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	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 NO_x and mass of particles smaller than 2.5 μm (PM_2.5). 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 NO_x were similar to each other, and their concentrations decreased more rapidly than the concentration of PM_2.5. 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.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/248878
专题	地球科学
推荐引用方式 GB/T 7714	Krista Luoma, Jarkko V. Niemi, Aku Helin, Minna Aurela, Hilkka Timonen, Aki Virkkula, Topi Rönkkö, Anu Kousa, Pak Lun Fung, Tareq Hussein, and Tuukka Petäjä. Spatiotemporal variation and trends of equivalent black carbon in the Helsinki metropolitan area in Finland[J]. Atmospheric Chemistry and Physics,2020.
APA	Krista Luoma, Jarkko V. Niemi, Aku Helin, Minna Aurela, Hilkka Timonen, Aki Virkkula, Topi Rönkkö, Anu Kousa, Pak Lun Fung, Tareq Hussein, and Tuukka Petäjä.(2020).Spatiotemporal variation and trends of equivalent black carbon in the Helsinki metropolitan area in Finland.Atmospheric Chemistry and Physics.
MLA	Krista Luoma, Jarkko V. Niemi, Aku Helin, Minna Aurela, Hilkka Timonen, Aki Virkkula, Topi Rönkkö, Anu Kousa, Pak Lun Fung, Tareq Hussein, and Tuukka Petäjä."Spatiotemporal variation and trends of equivalent black carbon in the Helsinki metropolitan area in Finland".Atmospheric Chemistry and Physics (2020).