Responses of gaseous sulfuric acid and particulate sulfate to reduced SO2 concentration: A perspective from long-term measurements in Beijing

Li, Xiaoxiao; Zhao, Bin; Zhou, Wei; Shi, Huli; Yin, Rujing; Cai, Runlong; Yang, Dongsen; Daellenbach, Kaspar R.; Deng, Chao; Fu, Yuan; Qiao, Xiaohui; Wang, Lin; Yan, Chao; Kulmala, Markku; Zheng, Jun; Hao, Jiming; Jiang, Jingkun

doi:10.1016/j.scitotenv.2020.137700

Cited by 35 publications

(33 citation statements)

References 76 publications

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“…Left axis shows the fraction of sulfate, nitrate, and ammonium in total SNA (colored bars), while right axis shows total SNA concentrations (μg m −3 ) as indicated by the red crosses (+) for each month. The measurement site (40.00°N, 116.32°E) is located at Tsinghua University in Beijing (Li, Zhao, et al, 2020).…”

Section: Resultsmentioning

confidence: 99%

“…Nitrate exhibits an especially large difference, showing a rapid decrease in summer (−6.1% yr −1 ) but almost no change in winter (−0.3% yr −1 ). We further plot in Figures 2c and 2d simulated SNA concentrations (red crosses) and their relative fractions (color bars) over a gridbox in Beijing, as well as observed SNA from a speciation site in the same gridbox (Figures 2e and 2f) (Li, Zhao, et al, 2020). Simulation results agree with speciation data, both showing that SNA declined faster in summer than in winter (also see Text S1).…”

Section: Resultsmentioning

confidence: 99%

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Wintertime Particulate Matter Decrease Buffered by Unfavorable Chemical Processes Despite Emissions Reductions in China

Leung

Shi

Zhao

et al. 2020

Geophysical Research Letters

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Extreme and persistent haze events frequently occur during wintertime China. While recent emissions reductions reduced annual mean fine particulate matter (PM2.5) concentrations over eastern China, their effectiveness on wintertime PM2.5 trend remains uncertain. We use observations and model simulations to quantify seasonal differences in PM2.5 trends and investigate the underlying chemical mechanisms driving such differences. We find a much slower decrease in observed wintertime PM2.5 (−3.2% yr−1) since 2014, in contrast to a drastic summertime decrease (−10.3% yr−1). Simulations show two previously underappreciated mechanisms buffering wintertime PM2.5 decrease, including an increase in oxidation capacity due to nitrogen oxides (NOx) reductions under wintertime volatile organic compound (VOC)‐limited chemistry, and an enhanced conversion of nitric acid to nitrate by ammonia due to sulfur dioxide reductions. Our findings suggest that control policies targeting VOC and deep NOx reductions are needed to improve wintertime PM2.5 air quality over China.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Wintertime Particulate Matter Decrease Buffered by Unfavorable Chemical Processes Despite Emissions Reductions in China

Leung

Shi

Zhao

et al. 2020

Geophysical Research Letters

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“…In the absence of direct CCN measurements, the potential contribution of new particles to the CCN population can be estimated from the particle number size distribution (Lihavainen et al, 2003;Rose et al, 2017). Theoretically, particles larger than 50 nm (i.e., 80 nm) can be activated as CCN under quite high (moderate) supersaturation (Dusek et al, 2006;Petters and Kreidenweis, 2007;Ma et al, 2016), and particles larger than 100 nm can directly impact the climate by scattering and absorbing solar radiation (Charlson et al, 1992;Seinfeld and Pandis, 2012).…”

Section: Ccn Parametersmentioning

confidence: 99%

Increased new particle yields with largely decreased probability of survival to CCN size at the summit of Mt. Tai under reduced SO<sub>2</sub> emissions

et al. 2021

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Abstract. Because anthropogenic sulfur dioxide (SO2) emissions have decreased considerably in the last decade, PM2.5 pollution in China has been alleviated to some extent. However, the effects of reduced SO2 on the particle number concentrations and subsequent contributions of grown new particles to cloud condensation nuclei (CCN) populations, particularly at high altitudes with low aerosol number loadings, are poorly understood. In contrast, the increase in provincial forest areas in China with rapid afforestation over the last few decades expectedly increases the biogenic emissions of volatile organic compounds and their oxidized products as nucleating precursors therein. In this study, we evaluated the campaign-based measurements made at the summit of Mt. Tai (1534 m a.s.l.) from 2007 to 2018. With the decrease in SO2 mixing ratios from 15 ± 13 ppb in 2007 to 1.6 ± 1.6 ppb in 2018, the apparent formation rate (FR) of new particles and the net maximum increase in the nucleation-mode particle number concentration (NMINP) in the spring campaign of 2018 was 2- to 3-fold higher than those in the spring campaign of 2007 with almost the same occurrence frequency of new particle formation (NPF) events. In contrast, the campaign-based comparison showed that the occurrence frequency, in which the maximum geometric median diameter of the grown new particles (Dpgmax) was > 50 nm, decreased considerably from 43 %–78 % of the NPF events before 2015 to < 12 % in 2017–2018. Assuming > 50 nm as a CCN threshold size at high supersaturations, the observed net CCN production decreased from 3.7 × 103 cm−3 (on average) in the five campaigns before 2015 to 1.0 × 103 cm−3 (on average) in the two campaigns in 2017–2018. We argue that the increases in the apparent FR and NMINP are mainly determined by the availability of organic precursors that participate in nucleation and initial growth, whereas the decrease in the growth probability is caused by the reduced emissions of anthropogenic precursors. However, large uncertainties still exist because of a lack of data on the chemical composition of these smaller particles.

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“…Sulfuric acid formed by oxidation of ambient SO 2 is considered a key precursor species for ambient nucleation in the continental atmosphere. A large decrease in SO 2 concentrations has been observed across China in the past decade (Krotkov et al, 2016;X. Li et al, 2020;).…”

Section: Factors Affecting the Occurrence Frequency And Four Metrics Of The Npf Eventsmentioning

confidence: 99%

Investigation of Particle Number Concentrations and New Particle Formation With Largely Reduced Air Pollutant Emissions at a Coastal Semi‐Urban Site in Northern China

Zhu

Shen

et al. 2021

JGR Atmospheres

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Particle number concentrations (PNCs) and particle number size distributions (PNSDs) in ambient air are essential to evaluate climate effects, characterize human exposure, and formulate relevant protection policies (Dusek et al., 2006;Kumar et al., 2010;Vu et al., 2015). For example, atmospheric particles with a diameter <50 nm reportedly act as cloud condensation nuclei (CCN) in exceptionally high supersaturation (SS) conditions, such as >0.6%, whereas particles with a diameter >80 nm significantly contribute to the CCN population at SS conditions of ∼0.

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Responses of gaseous sulfuric acid and particulate sulfate to reduced SO2 concentration: A perspective from long-term measurements in Beijing

Cited by 35 publications

References 76 publications

Wintertime Particulate Matter Decrease Buffered by Unfavorable Chemical Processes Despite Emissions Reductions in China

Wintertime Particulate Matter Decrease Buffered by Unfavorable Chemical Processes Despite Emissions Reductions in China

Increased new particle yields with largely decreased probability of survival to CCN size at the summit of Mt. Tai under reduced SO<sub>2</sub> emissions

Investigation of Particle Number Concentrations and New Particle Formation With Largely Reduced Air Pollutant Emissions at a Coastal Semi‐Urban Site in Northern China

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Responses of gaseous sulfuric acid and particulate sulfate to reduced SO2 concentration: A perspective from long-term measurements in Beijing

Cited by 35 publications

References 76 publications

Wintertime Particulate Matter Decrease Buffered by Unfavorable Chemical Processes Despite Emissions Reductions in China

Wintertime Particulate Matter Decrease Buffered by Unfavorable Chemical Processes Despite Emissions Reductions in China

Increased new particle yields with largely decreased probability of survival to CCN size at the summit of Mt. Tai under reduced SO&lt;sub&gt;2&lt;/sub&gt; emissions

Investigation of Particle Number Concentrations and New Particle Formation With Largely Reduced Air Pollutant Emissions at a Coastal Semi‐Urban Site in Northern China

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Increased new particle yields with largely decreased probability of survival to CCN size at the summit of Mt. Tai under reduced SO<sub>2</sub> emissions