Variations in submicron aerosol liquid water content and the contribution of chemical components during heavy aerosol pollution episodes in winter in Beijing

Shen, Xiaojing; Sun, Junying; Zhang, X.Y.; Zhang, Y.M.; Zhong, Junting; Wang, X.; Wang, Y.Q.; Xia, Chun

doi:10.1016/j.scitotenv.2019.07.327

Cited by 21 publications

(17 citation statements)

References 27 publications

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“…This was a self-amplifying process between the ALWC and SIA that could further enhance the particle mass loading in the ambient; lower wind speed leads to poorer dispersion conditions, contributing to the accumulation of air pollutants . We showed that low RH and high wind speed in 2017 led to lower observed PM 1 concentrations, consistent with Vu et al and Cheng et al…”

Section: Discussionsupporting

confidence: 89%

“…This was a selfamplifying process between the ALWC and SIA that could further enhance the particle mass loading in the ambient; lower wind speed leads to poorer dispersion conditions, contributing to the accumulation of air pollutants. 38 We showed that low RH and high wind speed in 2017 led to lower observed PM 1 concentrations, 40 consistent with Vu et al 8 and Cheng et al 10 Changes on PM 1 Chemistry and Challenges for Future Air Pollution Control. With the implementation of clean air actions, the chemistry of PM 1 in the 10 years changed substantially.…”

Section: Environmental Science and Technologysupporting

confidence: 86%

“…5,12,38 The high RH was one prerequisite for the rapid sulfate formation via multiphase reactions. 39 Shen et al, 40 found an exponential trend of the aerosol liquid water content (ALWC) with the RH. The high mass loading of ALWC promoted the secondary formation processes of the secondary inorganics aerosol (SIA).…”

Section: Environmental Science and Technologymentioning

confidence: 99%

See 2 more Smart Citations

Significant Changes in Chemistry of Fine Particles in Wintertime Beijing from 2007 to 2017: Impact of Clean Air Actions

Zhang

Sun

et al. 2019

Environ. Sci. Technol.

105

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The Beijing government implemented a number of clean air action plans to improve air quality in the last 10 years, which contributed to changes in the concentration of fine particles and their compositions. However, quantifying the impacts of these interventions is challenging as meteorology masks the real changes in observed concentrations. Here, we applied a machine learning technique to decouple the effect of meteorology and evaluate the changes in the chemistry of nonrefractory PM 1 (particulate matter less than 1 μm) in winter 2007, 2016, and 2017 as a result of the clean air actions. The observed mass concentrations of PM 1 were 74.6, 90.2, and 36.1 μg m −3 in the three winters, while the deweathered concentrations were 74.2, 78.7, and 46.3 μg m −3 , respectively. The deweathered concentrations of PM 1 , organics, sulfate, ammonium, chloride, SO 2 , NO 2 , and CO decreased by −38, −46, −59, −24, −51, −89, −16, and −52% in 2017 in comparison to 2007. On the contrary, the deweathered concentration of nitrates increased by 4%. Our results indicate that the clean air actions implemented in 2017 were highly effective in reducing ambient concentrations of SO 2 , CO, and PM 1 organics, sulfate, ammonium, and chloride, but the control of nitrate and PM 1 organics remains a major challenge.

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Section: Discussionsupporting

confidence: 89%

Section: Environmental Science and Technologysupporting

confidence: 86%

See 1 more Smart Citation

Significant Changes in Chemistry of Fine Particles in Wintertime Beijing from 2007 to 2017: Impact of Clean Air Actions

Zhang

Sun

et al. 2019

Environ. Sci. Technol.

105

View full text Add to dashboard Cite

show abstract

“…This ALWC in Delhi is five times higher than reported during winter in Beijing (45 μg/m 3 ). 27 The maximum daily ALWC in Delhi in January 2017 was 740 μg/m 3 , which is 3.5 times higher than the highest daily value recorded in Beijing (210 μg/m 3 ). 26 , 27 ALWC in Delhi is greater than at any of the observational sites investigated globally in previous studies.…”

Section: Resultsmentioning

confidence: 79%

“… 25 The ALWC contribution can double particulate matter loading in Beijing, with daily averages of up to 210 μg/m 3 . 26 , 27 The high concentration of secondary inorganic aerosol in winter in Beijing, in particular following the co-condensation of nitrate with water vapor, 3 , 45 was found to be the driving factor for ALWC production that facilitated haze development. 26 Particulate matter pollution in the Indian capital Delhi is comparable or even more severe than that in Beijing 28 and leads to ∼10,000 premature deaths per year in Delhi 29 − 34 In situ observations indicate that aerosol in Delhi has a greater capacity to take up water than in Beijing, 19 , 34 and ALWC may therefore play a more critical role in the deterioration of air quality.…”

Section: Introductionmentioning

confidence: 99%

Ammonium Chloride Associated Aerosol Liquid Water Enhances Haze in Delhi, India

Chen

Wang

Nenes

et al. 2022

Environ. Sci. Technol.

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The interaction between water vapor and atmospheric aerosol leads to enhancement in aerosol water content, which facilitates haze development, but its concentrations, sources, and impacts remain largely unknown in polluted urban environments. Here, we show that the Indian capital, Delhi, which tops the list of polluted capital cities, also experiences the highest aerosol water yet reported worldwide. This high aerosol water promotes secondary formation of aerosols and worsens air pollution. We report that severe pollution events are commonly associated with high aerosol water which enhances light scattering and reduces visibility by 70%. Strong light scattering also suppresses the boundary layer height on winter mornings in Delhi, inhibiting dispersal of pollutants and further exacerbating morning pollution peaks. We provide evidence that ammonium chloride is the largest contributor to aerosol water in Delhi, making up 40% on average, and we highlight that regulation of chlorine-containing precursors should be considered in mitigation strategies.

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Complex interplay between organic and secondary inorganic aerosols with ambient relative humidity implicates the aerosol liquid water content over India during wintertime

Gopinath

Raj

Kommula

et al. 2022

Preprint

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Aerosol Liquid Water Content (ALWC), a ubiquitous component of atmospheric aerosols, contributes to total aerosol mass burden, modulating atmospheric chemistry through aerosol surface reactions and reducing atmospheric visibility. However, the complex dependency of ALWC on aerosol chemistry and relative humidity (RH) in the Indian region remains poorly characterized. Here, we combine available measurements of aerosol chemical composition with thermodynamic model ISORROPIA2.1 to reveal a comprehensive picture of ALWC in fine mode aerosols during the winter season in the Indian region. The fac-tors modulating ALWC are primarily dependent on the RH, such that the effect of aerosol dry mass and hygroscopicity are significant at high RH while the effect of hygroscopicity loses its significance as RH is lowered. ALWC, depending upon the particle hygroscopicity, displays a sharp non-linear rise beyond a critical value of ambient RH. Further analysis coupling WRF-Chem simulation with ISORROPIA2.1 revealed significant spatial heterogeneity in ALWC over India, strongly associating with regions of high aerosol loading and RH. The Indo-Gangetic Plain is consequently observed to be a hotspot of higher ALWC, which explains the prevalent conditions of haze and smog during winter in the region. Our findings re-emphasize that high aerosol mass resulting from intense pollution is vital in modulating aerosol-climate interaction under favorable meteorological conditions. They suggest the need for pollution control strategies to be directed at the reduction in emissions of specific species like NH3 and NOx, which were observed to contribute to the enhancement of PM and ALWC during wintertime in the region.

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Variations in submicron aerosol liquid water content and the contribution of chemical components during heavy aerosol pollution episodes in winter in Beijing

Cited by 21 publications

References 27 publications

Significant Changes in Chemistry of Fine Particles in Wintertime Beijing from 2007 to 2017: Impact of Clean Air Actions

Significant Changes in Chemistry of Fine Particles in Wintertime Beijing from 2007 to 2017: Impact of Clean Air Actions

Ammonium Chloride Associated Aerosol Liquid Water Enhances Haze in Delhi, India

Complex interplay between organic and secondary inorganic aerosols with ambient relative humidity implicates the aerosol liquid water content over India during wintertime

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