Estimating the influence of transport on aerosol size distributions during new particle formation events

Cai, Runlong; Chandra, Indra; Yang, Dongsen; Yao, Lei; Fu, Yuan; Li, Xiaoxiao; Lu, Yiqun; Hao, Jiming; Ma, Yan; Wang, Lin; Zheng, Jun; Seto, Takafumi; Jiang, Jingkun

doi:10.5194/acp-18-16587-2018

Cited by 23 publications

(12 citation statements)

References 34 publications

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“…This is because only the condensation of sulfuric acid is considered although other vapors may also contribute to new particle growth. The enhancement due to Van der Waals forces is considered when calculating the coagulation coefficient (Alam, 1987;Chan and Mozurkewich, 2001;Stolzenburg et al, 2020). The appearance time retrieved from the measured aerosol size distributions was smoothed before estimating the particle growth rate.…”

Section: Application In Atmospheric Measurementsmentioning

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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Section: Application In Atmospheric Measurementsmentioning

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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“…Studies suggest that the size distribution of hot and undiluted motor vehicle exhaust typically contains a mode of nonvolatile particles smaller than 10 nm (core mode) and the larger mode (soot mode) with diameters between 30 and 100 nm (Harris and Maricq, 2001;Rönkkö et al, 2007). When exhaust is diluted and cooled in the atmosphere, gaseous compounds in the exhaust can form new nucleation mode particles and condense on core and soot mode particles (Charron and Harrison, 2003;Rönkkö et al, 2007). It was recently shown that dilution and cooling of exhaust also produces significant concentrations of particles smaller than 3 nm (Rönkkö et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

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

Kontkanen

Deng

et al. 2020

Atmos. Chem. Phys.

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Abstract. The climate and air quality effects of aerosol particles depend on the number and size of the particles. In urban environments, a large fraction of aerosol particles originates from anthropogenic emissions. To evaluate the effects of different pollution sources on air quality, knowledge of size distributions of particle number emissions is needed. Here we introduce a novel method for determining size-resolved particle number emissions, based on measured particle size distributions. We apply our method to data measured in Beijing, China, to determine the number size distribution of emitted particles in a diameter range from 2 to 1000 nm. The observed particle number emissions are dominated by emissions of particles smaller than 30 nm. Our results suggest that traffic is the major source of particle number emissions with the highest emissions observed for particles around 10 nm during rush hours. At sizes below 6 nm, clustering of atmospheric vapors contributes to calculated emissions. The comparison between our calculated emissions and those estimated with an integrated assessment model GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) shows that our method yields clearly higher particle emissions at sizes below 60 nm, but at sizes above that the two methods agree well. Overall, our method is proven to be a useful tool for gaining new knowledge of the size distributions of particle number emissions in urban environments and for validating emission inventories and models. In the future, the method will be developed by modeling the transport of particles from different sources to obtain more accurate estimates of particle number emissions.

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“…Population balance equations, derived from aerosol general dynamic equation, have been used to estimate particle formation rates Kulmala et al, 2012), particle growth rates (Kuang et al, 2012), and the effect of transport on aerosol particle size distribution (Cai et al, 2018). In this study, we use the population balance method to estimate particle number emissions into a column extending from the ground to the top of the atmospheric mixing layer (ML).…”

Section: Balance Equation For Estimating Particle Number Emissionsmentioning

confidence: 99%

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

Kontkanen¹,

Deng²,

Fu³

et al. 2020

Preprint

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Abstract. The climate and air quality effects of aerosol particles depend on the number and size of the particles. In urban environments, a large fraction of aerosol particles originates from anthropogenic emissions. To evaluate the effects of different pollution sources on air quality, knowledge of size distributions of particle number emissions is needed. Here we introduce a novel method for determining size-resolved particle number emissions based on measured particle size distributions. We apply our method to data measured in Beijing, China, to determine the number size distribution of emitted particles in diameter range from 2 to 1000 nm. The observed particle number emissions are dominated by emissions of particles smaller than 30 nm. Our results suggest that traffic is the major source of particle number emissions with the highest emissions observed for particles around 10 nm during rush hours. At sizes below 6 nm, clustering of atmospheric vapors contributes to calculated emissions. The comparison between our calculated emissions and those estimated with an integrated assessment model GAINS shows that our method yields clearly higher particle emissions at sizes below 60 nm, but at sizes above that the two methods agree well. Overall, our method is proven to be a useful tool for gaining new knowledge of size distributions of particle number emissions in urban environments.

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Estimating the influence of transport on aerosol size distributions during new particle formation events

Cited by 23 publications

References 34 publications

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

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

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

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

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