Seasonal variations in the highly time-resolved aerosol composition, sources and chemical processes of background submicron particles in the North China Plain

Li, Jiayun; Cao, Liming; Gao, Wenkang; He, Lingyan; Yan, Yong; He, Yuexin; Pan, Yuepeng; Ji, Dongsheng; Liu, Zirui; Wang, Yuesi

doi:10.5194/acp-21-4521-2021

Cited by 21 publications

(7 citation statements)

References 58 publications

(105 reference statements)

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“…During this field observation, the mass concentrations of NR-PM 1 were in the range of 2.5-44.8 µg m −3 , with an average of 12.7 ± 5.7 µg m −3 , which is close to those observed in the North China Plain in autumn 2019 (15.1 µg m −3 ; J. Li et al, 2021), and were much lower than those (41.3 ± 42.7 µg m −3 ) observed in Beijing in autumn 2012 (Hu et al, 2017). The mean mass concentration of BC was 0.29 ± 0.17 µg m −3 , with the range of 0.1-1.0 µg m −3 .…”

Section: Chemical Compositions Of Pmsupporting

confidence: 77%

Evolution of source attributed organic aerosols and gases in a megacity of central China

Liu

Liu²,

Kong³

et al. 2022

Atmos. Chem. Phys.

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Abstract. The secondary production of oxygenated organic aerosol (OOA) impacts air quality, climate, and human health. The importance of various sources in contributing to the OOA loading and associated different ageing mechanisms remains to be elucidated. Here we present a concurrent observation and factorization analysis on the mass spectra of organic aerosol (OA) by a high-resolution aerosol mass spectrometer and volatile organic compounds (VOCs) by a proton transfer reaction mass spectrometer in Wuhan, a megacity in central China, during autumn. The full mass spectra of organics with two principle anthropogenic sources were identified as the traffic and cooking sources, for their primary emission profiles in aerosol and gas phases, the evolutions, and their respective roles in producing OOA and secondary VOCs. Primary emissions in gas and aerosol phases both contributed to the production of OOA. The photooxidation of traffic sources from the morning rush hour caused a 2.5 fold increase in OOA mass in a higher oxidation state (oxygen-to-carbon ratio as O/C =0.72), co-producing gas phase carboxylic acids, while, at night, cooking aerosols and VOCs (particularly acrolein and hexanal) importantly caused the nocturnal formation of oxygenated intermediate VOCs, increasing OOA mass by a factor of 1.7 (O/C =0.42). The daytime and nighttime formation of secondary aerosols, as contributed by different sources, was found to be modulated by solar radiation and air moisture, respectively. The environmental policy should, therefore, consider the primary emissions and their respective ageing mechanisms influenced by meteorological conditions.

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Section: Chemical Compositions Of Pmsupporting

confidence: 77%

Evolution of source attributed organic aerosols and gases in a megacity of central China

Liu

Liu²,

Kong³

et al. 2022

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…1. During this field observation, the mass concentrations of NR-PM1 were in the range of 2.5 -44.8 µg m -3 , with an average of 12.7 ± 5.7 µg m -3 , which is close to those observed in the North China Plain in autumn 2019 (15.1 µg m -3 ) (Li et al, 2021a), and was much lower than that (41.3 ± 42.7 µg m -3 ) observed in Beijing in autumn 2012 (Hu et al, 2017). The mean mass concentration of BC was 0.29 ± 0.17 µg m -3 with the range of 0.1 -1.0 µg m -3 .…”

Section: Chemical Compositions Of Pm1supporting

confidence: 74%

Evolution of source attributed organic aerosols and gases in a megacity of central China

Liu

Kong

et al. 2022

Preprint

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Abstract. The secondary production of the oxygenated organic aerosol (OOA) impacts air quality, climate and human health. The importance of various sources in contributing to the OOA loading and associated different aging mechanisms remains to be elucidated. Here we present concurrent observation and factorization analysis on the mass spectra of organic aerosol (OA) by a high-resolution aerosol mass spectrometer and volatile organic compounds (VOCs) by a proton-transfer-reaction mass spectrometer in Wuhan, a megacity in central China during autumntime. The full mass spectra of organics with two principle anthropogenic sources were identified as the traffic and cooking sources, for their primary emission profiles in aerosol and gas phases, the evolutions, and their respective roles in producing OOA and secondary VOCs. Primary emissions in gas and aerosol phases both contributed to the production of OOA. The photooxidation of traffic sources from morning rush-hour caused 2.5-folds increase of OOA mass in a higher oxidation state (O / C = 0.72), coproducing gas-phase carboxylic acids; while at night, cooking aerosols and VOCs (particularly acrolein and hexanal) importantly caused the nocturnal formation of oxygenated intermediate VOCs, increasing OOA mass by a factor of 1.7 (O / C = 0.42). The daytime and nighttime formation of secondary aerosols as contributed by different sources, was found to be modulated by solar radiation and air moisture respectively. The environmental policy should therefore consider the primary emissions and their respective ageing mechanisms influenced by meteorological conditions.

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“…Although size-resolved chemical composition was not measured in this study, it can be inferred from J. Li et al (2021) that the mass fraction of SIA increased from 49 % (49 %) to 55 % (61 %), with particle size increasing from 150 to 300 nm in autumn (winter) in the NCP. The other is the collapse and restructuring effect occurred for soot-containing particles during aging processes (Ghazi and Olfert, 2013;Pagels et al, 2009), leading to a more sphere-like particles or a more dense morphology of large particles.…”

Section: Resultsmentioning

confidence: 72%

“…S1, one of the prevailing winds at the site is from the southwest with relatively high wind speed, possibly indicating the influence of regional transport from southern Hebei province. Overall, the sampling site is influenced by both local emissions from nearby villages and regional transport and can represent the average pollution conditions of the rural area of the North China Plain (NCP) well (G. Li et al, 2021).…”

Section: Sampling Site and Instrumentationmentioning

confidence: 99%

Bimodal distribution of size-resolved particle effective density: results from a short campaign in a rural environment over the North China Plain

Zhou

Wang

et al. 2022

Atmos. Chem. Phys.

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Abstract. Effective density is one of the most important physical properties of atmospheric particles. It is closely linked to particle chemical composition and morphology and could provide special information on particle emissions and aging processes. In this study, size-resolved particle effective density was measured with a combined differential mobility analyzer–centrifugal particle mass analyzer–condensation particle counter (DMA–CPMA–CPC) system in autumn 2019 as part of the Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain (McFAN). With a newly developed flexible Gaussian fit algorithm, frequent (77 %–87 %) bimodal distribution of particle effective density is identified, with a low-density mode (named sub-density mode) accounting for 22 %–27 % of the total number of observed particles. The prevalence of the sub-density mode is closely related to fresh black carbon (BC) emissions. The geometric mean for the main density mode (ρ‾eff,main) increases from 1.18 ± 0.10 g cm−3 (50 nm) to 1.37 ± 0.12 g cm−3 (300 nm) due to a larger fraction of high-density components and a more significant restructuring effect at large particle sizes but decreases from 0.89 ± 0.08 g cm−3 (50 nm) to 0.62 ± 0.12 g cm−3 (300 nm) for the sub-density mode (ρ‾eff,sub), which could be mainly ascribed to the agglomerate effect of BC. ρ‾eff,main and ρ‾eff,sub show similar diurnal cycles with peaks in the early afternoon, mainly attributed to the increasing mass fraction of high material density components associated with secondary aerosol production, especially of secondary inorganic aerosol (SIA). To investigate the impact of chemical composition, bulk particle effective density was calculated based on measured chemical composition (ρeff,ACSM) and compared to the average effective density at 300 nm (ρ‾eff,tot,300nm). The best agreement between the two densities is achieved when assuming a BC effective density of 0.60 g cm−3. The particle effective density is highly dependent on SIA and BC mass fractions. The influence of BC on the effective density is even stronger than SIA, implying the importance and necessity of including BC in the estimate of effective density for ambient particles.

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Seasonal variations in the highly time-resolved aerosol composition, sources and chemical processes of background submicron particles in the North China Plain

Cited by 21 publications

References 58 publications

Evolution of source attributed organic aerosols and gases in a megacity of central China

Evolution of source attributed organic aerosols and gases in a megacity of central China

Evolution of source attributed organic aerosols and gases in a megacity of central China

Bimodal distribution of size-resolved particle effective density: results from a short campaign in a rural environment over the North China Plain

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