Size-resolved particle number emissions in Beijing determined from measured particle size distributions

Kontkanen, Jenni; Deng, Chao; Fu, Yuan; Dada, Lubna; Zhou, Ying; Cai, Jing; Daellenbach, Kaspar R.; Hakala, Simo; Kokkonen, Tom; Lin, Zongkai; Wang, Yonghong; Yan, Chao; Petäj̈ä, Tuukka; Jiang, Jingkun; Kulmala, Markku; Paasonen, Pauli

doi:10.5194/acp-20-11329-2020

Cited by 33 publications

(24 citation statements)

References 52 publications

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“…In the PMF analysis, size-resolved particle number concentrations were averaged to a 15 min resolution, and NPF days were excluded to better estimate contributions from the primary sources. NPF events were classified by the appearance of nucleation-mode particles showing signs of growth following the methods proposed by Dal Maso et al ( 2005) and Kulmala et al (2012). In this study, the classification relied on the particle number size distribution measured using the SMPS and a complementary NAIS (Neutral cluster and Air Ion Spectrometer, 2-42 nm; Manninen et al, 2011;Mirme and Mirme, 2013) for confirming our classification.…”

Section: Data Treatment and Source Apportionment Analysismentioning

confidence: 61%

Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

et al. 2020

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Abstract. Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76 % and 24 % of total particle number and organic aerosol (OA) mass, respectively. Similar source types, including particles related to vehicular emissions (1.6±1.1 µg m−3; 2.4±1.8×103 cm−3 and 5.5±2.8×103 cm−3 for two traffic-related components), cooking emissions (2.6±1.9 µg m−3 and 5.5±3.3×103 cm−3) and secondary aerosols (51±41 µg m−3 and 4.2±3.0×103 cm−3), were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm (“traffic-ultrafine”) and a component with a mode diameter of 100 nm (“traffic-fine”). Consistent with similar day- and nighttime diesel vehicle PM2.5 emissions estimated for the Beijing area, traffic-fine particles, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints) and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new particle formation, our results show that vehicular-related emissions (14 % and 30 % for ultrafine and fine particles, respectively) and cooking-activity-related emissions (32 %) dominate the particle number concentration, while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.

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Section: Data Treatment and Source Apportionment Analysismentioning

confidence: 61%

Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

et al. 2020

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“…In the urban environment, atmospheric Br was previously known to be strongly affected by traffic emissions since ethylene dibromide (C 2 H 4 Br 2 ) used to be used as an anti-knock compound in leaded gasoline (Glasow and Crutzen, 2014). Yet, since the phasing out of leaded gasoline, long-term atmospheric Br has exhibited a continuous decreasing trend for 2 to 3 decades in Germany (Lammel et al, 2002), and a similar situation is expected in Beijing as the usage of leaded gasoline was banned from the years around the 2000s in China (Cai et al, 2017).…”

Section: Introductionmentioning

confidence: 88%

Atmospheric gaseous hydrochloric and hydrobromic acid in urban Beijing, China: detection, source identification and potential atmospheric impacts

et al. 2021

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Abstract. Gaseous hydrochloric (HCl) and hydrobromic acid (HBr) are vital halogen species that play essential roles in tropospheric physicochemical processes. Yet, the majority of the current studies on these halogen species were conducted in marine or coastal areas. Detection and source identification of HCl and HBr in inland urban areas remain scarce, thus limiting the full understanding of halogen chemistry and potential atmospheric impacts in the environments with limited influence from the marine sources. Here, both gaseous HCl and HBr were concurrently measured in urban Beijing, China, during winter and early spring of 2019. We observed significant HCl and HBr concentrations ranging from a minimum value at 1 × 108 molecules cm−3 (4 ppt) and 4 × 107 molecules cm−3 (1 ppt) up to 6 × 109 molecules cm−3 (222 ppt) and 1 × 109 molecules cm−3 (37 ppt), respectively. The HCl and HBr concentrations are enhanced along with the increase of atmospheric temperature, UVB and levels of gaseous HNO3. Based on the air mass analysis and high correlations of HCl and HBr with the burning indicators (HCN and HCNO), gaseous HCl and HBr are found to be related to anthropogenic burning aerosols. The gas–particle partitioning may also play a dominant role in the elevated daytime HCl and HBr. During the daytime, the reactions of HCl and HBr with OH radicals lead to significant production of atomic Cl and Br, up to 2 × 104 molecules cm−3 s−1 and 8 × 104 molecules cm−3 s−1, respectively. The production rate of atomic Br (via HBr + OH) is 2–3 times higher than that of atomic Cl (via HCl + OH), highlighting the potential importance of bromine chemistry in the urban area. On polluted days, the production rates of atomic Cl and Br are faster than those on clean days. Furthermore, our observations of elevated HCl and HBr may suggest an important recycling pathway of halogen species in inland megacities and may provide a plausible explanation for the widespread halogen chemistry, which could affect the atmospheric oxidation in China.

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“…New particle formation (NPF) is frequently observed in various atmospheric environments (Kulmala et al, 2004;Kerminen et al, 2018;Nieminen et al, 2018;Lee et al, 2019). It contributes significantly to the number concentrations of aerosols and cloud condensation nuclei (CCN) and hence impacts the global climate (Kuang et al, 2009; Published by Copernicus Publications on behalf of the European Geosciences Union.…”

Section: Introductionmentioning

confidence: 99%

Impacts of coagulation on the appearance time method for new particle growth rate evaluation and their corrections

Cai

et al. 2021

Atmos. Chem. Phys.

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Abstract. The growth rate of atmospheric new particles is a key parameter that determines their survival probability of becoming cloud condensation nuclei and hence their impact on the climate. There have been several methods to estimate the new particle growth rate. However, due to the impact of coagulation and measurement uncertainties, it is still challenging to estimate the initial growth rate of new particles, especially in polluted environments with high background aerosol concentrations. In this study, we explore the influences of coagulation on the appearance time method to estimate the growth rate of sub-3 nm particles. The principle of the appearance time method and the impacts of coagulation on the retrieved growth rate are clarified via derivations. New formulae in both discrete and continuous spaces are proposed to correct for the impacts of coagulation. Aerosol dynamic models are used to test the new formulae. New particle formation in urban Beijing is used to illustrate the importance of considering the impacts of coagulation on the sub-3 nm particle growth rate and its calculation. We show that the conventional appearance time method needs to be corrected when the impacts of coagulation sink, coagulation source, and particle coagulation growth are non-negligible compared to the condensation growth. Under the simulation conditions with a constant concentration of non-volatile vapors, the corrected growth rate agrees with the theoretical growth rates. However, the uncorrected parameters, e.g., vapor evaporation and the variation in vapor concentration, may impact the growth rate obtained with the appearance time method. Under the simulation conditions with a varying vapor concentration, the average bias in the corrected 1.5–3 nm particle growth rate ranges from 6 %–44 %, and the maximum bias in the size-dependent growth rate is 150 %. During the test new particle formation event in urban Beijing, the corrected condensation growth rate of sub-3 nm particles was in accordance with the growth rate contributed by sulfuric acid condensation, whereas the conventional appearance time method overestimated the condensation growth rate of 1.5 nm particles by 80 %.

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Size-resolved particle number emissions in Beijing determined from measured particle size distributions

Cited by 33 publications

References 52 publications

Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

Atmospheric gaseous hydrochloric and hydrobromic acid in urban Beijing, China: detection, source identification and potential atmospheric impacts

Impacts of coagulation on the appearance time method for new particle growth rate evaluation and their corrections

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