Emission Regulations Altered the Concentrations, Origin, and Formation of Carbonaceous Aerosols in the Tokyo Metropolitan Area

Miyakawa, Takuma; Kanaya, Yugo; Komazaki, Yuichi; Miyoshi, Takao; Nara, Hideki; Takami, Akinori; Moteki, Nobuhiro; Koike, M.; Kondo, Yutaka

doi:10.4209/aaqr.2015.11.0624

Cited by 4 publications

(2 citation statements)

References 34 publications

(43 reference statements)

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“…These results are consistent with those in previous studies (L. Tao et al, 2017;Lang et al, 2017). The contribution of TC to PM 2.5 , 21.3 % ± 15.8 %, is also similar to that reported in previous studies, listed in Table S4, for example, at urban sites of Hong Kong, China (23.5 %-23.6 % in 2013), and Hasselt (23 %) and Mechelen (24 %) in northern Belgium, rural sites in Europe (19 %-20 %), and some sites in India (on average 20 %; Bisht et al, 2015;Sarin, 2010, 2012), but lower than those observed historically at multiple sites in China (on average 27 %; L. ), and many sites in the USA, like Fresno (43.2 %), Los Angeles (36.9 %) and Philadelphia (33.3 %) (Na et al, 2004). Compared to previous studies in Beijing (Table S4), the TC-to-PM 2.5 ratio became smaller in this study, indicating a relatively lower contribution from carbonaceous aerosols to PM 2.5 in this study.…”

Section: Pscf Methodsmentioning

confidence: 74%

“…This could be because vehicular emissions played an important role in the OC and EC loadings (Ji et al, 2019). As documented by previous studies (Schauer et al, 2002;Na et al, 2004), emission of gasoline vehicles results in an OC/EC ratio varying from 3 to 5 while that of diesel vehicles is below 1. The above results are consistent with previous studies which showed that gasoline and diesel vehicles give rise to higher CO emissions (Wu et al, 2016).…”

Section: Relationship Between Oc and Ec And With Gaseous Pollutantsmentioning

confidence: 70%

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Impact of air pollution control measures and regional transport on carbonaceous aerosols in fine particulate matter in urban Beijing, China: insights gained from long-term measurement

Gao

Maenhaut

et al. 2019

Atmos. Chem. Phys.

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Abstract. As major chemical components of airborne fine particulate matter (PM2.5), organic carbon (OC) and elemental carbon (EC) have vital impacts on air quality, climate change, and human health. Because OC and EC are closely associated with fuel combustion, it is helpful for the scientific community and policymakers assessing the efficacy of air pollution control measures to study the impact of control measures and regional transport on OC and EC levels. In this study, hourly mass concentrations of OC and EC associated with PM2.5 were semi-continuously measured from March 2013 to February 2018. The results showed that annual mean OC and EC concentrations declined from 14.0 to 7.7 µg m−3 and from 4.0 to 2.6 µg m−3, respectively, from March 2013 to February 2018. In combination with the data of OC and EC in previous studies, an obvious decreasing trend in OC and EC concentrations was found, which was caused by clean energy policies and effective air pollution control measures. However, no obvious change in the ratios of OC and EC to the PM2.5 mass (on average, 0.164 and 0.049, respectively) was recorded, suggesting that inorganic ions still contributed a lot to PM2.5. Based on the seasonal variations in OC and EC, it appeared that higher OC and EC concentrations were still observed in the winter months, with the exception of winter of 2017–2018. Traffic policies executed in Beijing resulted in nighttime peaks of OC and EC, caused by heavy-duty vehicles and heavy-duty diesel vehicles being permitted to operate from 00:00 to 06:00 (China standard time, UTC+8, for all times throughout the paper). In addition, the fact that there was no traffic restriction in weekends led to higher concentrations on weekends compared to weekdays. Significant correlations between OC and EC were observed throughout the study period, suggesting that OC and EC originated from common emission sources, such as exhaust of vehicles and fuel combustion. OC and EC levels increased with enhanced SO2, CO, and NOx concentrations while the O3 and OC levels were enhanced simultaneously when O3 concentrations were higher than 50 µg m−3. Non-parametric wind regression analysis was performed to examine the sources of OC and EC in the Beijing area. It was found that there were distinct hot spots in the northeast wind sector at wind speeds of approximately 0–6 km h−1, as well as diffuse signals in the southwestern wind sectors. Source areas further away from Beijing were assessed by potential source contribution function (PSCF) analysis. A high-potential source area was precisely pinpointed, which was located in the northwestern and southern areas of Beijing in 2017 instead of solely in the southern areas of Beijing in 2013. This work shows that improvement of the air quality in Beijing benefits from strict control measures; however, joint prevention and control of regional air pollution in the regions is needed for further improving the air quality. The results provide a reference for controlling air pollution caused by rapid economic development in developing countries.

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Section: Pscf Methodsmentioning

confidence: 74%

Section: Relationship Between Oc and Ec And With Gaseous Pollutantsmentioning

confidence: 70%

Impact of air pollution control measures and regional transport on carbonaceous aerosols in fine particulate matter in urban Beijing, China: insights gained from long-term measurement

Gao

Maenhaut

et al. 2019

Atmos. Chem. Phys.

View full text Add to dashboard Cite

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Characterization of carbonaceous aerosols in Asian outflow in the spring of 2015: Importance of non-fossil fuel sources

Miyakawa

Komazaki

Zhu

et al. 2019

Atmospheric Environment

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Organic Molecular Tracers in PM2.5 at Urban Sites during Spring and Summer in Japan: Impact of Secondary Organic Aerosols on Water-Soluble Organic Carbon

Ikemori

Nishimura

Saito³

et al. 2021

Atmosphere

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To understand the characteristics of secondary organic aerosols (SOAs) and estimate their impact on water-soluble organic carbon (WSOC) in urban areas in Japan, we measured 17 organic tracers using gas chromatography–mass spectrometry from particulate matter with an aerodynamic diameter smaller than 2.5 μm collected at five urban sites in Japan during spring and summer. Most anthropogenic, monoterpene-derived, and isoprene-derived SOA tracers showed meaningful correlations with potential ozone in both these seasons. These results indicate that oxidants play an important role in SOAs produced during both seasons in urban cities in Japan. WSOC was significantly affected by anthropogenic and monoterpene-derived SOAs during spring and three SOA groups during summer at most of the sites sampled. The total estimated secondary organic carbons (SOCs), including mono-aromatic, di-aromatic, monoterpene-derived, and isoprene-derived SOCs, could explain the WSOC fractions of 39–63% in spring and 46–54% in summer at each site. Notably, monoterpene-derived and mono-aromatic SOCs accounted for most of the total estimated SOCs in both spring (85–93%) and summer (75–82%) at each site. These results indicate that SOAs significantly impact WSOC concentrations during both these seasons at urban sites in Japan.

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Emission Regulations Altered the Concentrations, Origin, and Formation of Carbonaceous Aerosols in the Tokyo Metropolitan Area

Cited by 4 publications

References 34 publications

Impact of air pollution control measures and regional transport on carbonaceous aerosols in fine particulate matter in urban Beijing, China: insights gained from long-term measurement

Impact of air pollution control measures and regional transport on carbonaceous aerosols in fine particulate matter in urban Beijing, China: insights gained from long-term measurement

Characterization of carbonaceous aerosols in Asian outflow in the spring of 2015: Importance of non-fossil fuel sources

Organic Molecular Tracers in PM2.5 at Urban Sites during Spring and Summer in Japan: Impact of Secondary Organic Aerosols on Water-Soluble Organic Carbon

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