Divergent Impacts of Biomass Burning and Fossil Fuel Combustion Aerosols on Fog‐Cloud Microphysics and Chemistry: Novel Insights From Advanced Aerosol‐Fog Sampling

Kuang, Ye; Xu, Weiqi; Tao, Jiangchuan; Luo, Biao; Liu, Li; Xu, Hanbin; Xu, Wanyun; Xue, Biao; Zhai, Miaomiao; Liu, Pengfei; Sun, Yele

doi:10.1029/2023gl107147

Cited by 5 publications

(1 citation statement)

References 46 publications

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“…Photolysis rates were measured using an ultra-fast CCD-spectrometer from METCON GmbH (Lippstadt, Germany), with a spectral resolution below 1.8 nm and a spectral range of 280 to 650 nm. Aerosol chemical composition (including NO − 3 , SO 2− 4 , NH + 4 and organic aerosol mass concentrations) was only measured during the autumn campaign using an aerosol mass spectrometer (AMS, Aerodyne Research, Inc., Billerica, MA, USA), with details on its calibration and data processing described in Kuang, et al's paper [51]. Aerosol hygroscopicity was measured using a self-assembled humidified nephelometer system, that can derive aerosol liquid water content as well as ambient aerosol surface area density, details on which can be found in Kuang, et al [52,53].…”

Section: Measurements and Datamentioning

confidence: 99%

The Impact of Agroecosystems on Nitrous Acid (HONO) Emissions during Spring and Autumn in the North China Plain

Zeng,

Xu,

Kuang

et al. 2024

Toxics

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Solar radiation triggers atmospheric nitrous acid (HONO) photolysis, producing OH radicals, thereby accelerating photochemical reactions, leading to severe secondary pollution formation. Missing daytime sources were detected in the extensive HONO budget studies carried out in the past. In the rural North China Plain, some studies attributed those to soil emissions and more recent studies to dew evaporation. To investigate the contributions of these two processes to HONO temporal variations and unknown production rates in rural areas, HONO and related field observations obtained at the Gucheng Agricultural and Ecological Meteorological Station during spring and autumn were thoroughly analyzed. Morning peaks in HONO frequently occurred simultaneously with those of ammonia (NH3) and water vapor both during spring and autumn, which were mostly caused by dew and guttation water evaporation. In spring, the unknown HONO production rate revealed pronounced afternoon peaks exceeding those in the morning. In autumn, however, the afternoon peak was barely detectable compared to the morning peak. The unknown afternoon HONO production rates were attributed to soil emissions due to their good relationship to soil temperatures, while NH3 soil emissions were not as distinctive as dew emissions. Overall, the relative daytime contribution of dew emissions was higher during autumn, while soil emissions dominated during spring. Nevertheless, dew emission remained the most dominant contributor to morning time HONO emissions in both seasons, thus being responsible for the initiation of daytime OH radical formation and activation of photochemical reactions, while soil emissions further maintained HONO and associated OH radial formation rates at a high level, especially during spring. Future studies need to thoroughly investigate the influencing factors of dew and soil emissions and establish their relationship to HONO emission rates, form reasonable parameterizations for regional and global models, and improve current underestimations in modeled atmospheric oxidation capacity.

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Section: Measurements and Datamentioning

confidence: 99%

The Impact of Agroecosystems on Nitrous Acid (HONO) Emissions during Spring and Autumn in the North China Plain

Zeng,

Xu,

Kuang

et al. 2024

Toxics

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Efficient Nitrate Formation in Fog Events Implicates Fog Interstitial Aerosols as Significant Drivers of Atmospheric Chemistry

Xu,

Kuang,

et al. 2024

Environ. Sci. Technol.

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Clouds and fogs, consisting of tiny water droplets formed by the condensation of water in supersaturated air, are vital in atmospheric chemistry, as they facilitate multiphase reactions. While measuring high-altitude cloud is challenging, fog as groundlevel clouds offer a unique opportunity for direct observation. In this study, we explored radiation fogs in the North China Plain using an advanced aerosol-fog sampling system to measure the chemical and physical properties of both inactivated interstitial aerosols and activated fog droplet residues. Our findings revealed that efficient nitrate formation primarily occurred on fog interstitial aerosols rather than within fog droplets, with observed fog interstitial aerosol nitrate net production rates reaching up to 3.6 μg m −3 h −1 . Box model simulations identified the hydrolysis of NO 2 and N 2 O 5 as key pathways for nitrate formation. NO 2 hydrolysis was often overlooked in previous studies, contributing 40−79 and 57−76% to total nitrate production during nighttime and daytime fog periods. This oversight suggests that substantial nitrate formation through hydrolysis reactions involving interstitial aerosols may have been neglected. Our results highlight the need for further research into the chemistry of cloud and fog interstitial aerosols and their inclusion in atmospheric chemistry models.

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Hysteresis in Water Content of Ultrafine Glassy Organic Aerosol Particles

Cheng,

Li,

Kuwata

2024

JGR Atmospheres

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Water content of aerosol particles is atmospherically important. Water content of organic aerosol (OA) particles has been estimated by assuming thermodynamic equilibrium. Here, we discovered that the hysteresis phenomenon occurred to water content of glassy ultrafine OA particles, demonstrating that thermodynamically non‐equilibrium states need to be considered. Hygroscopic growth for monodisperse ultrafine particles (sucrose and glucose) was investigated for the temperature range from 252 to 296 K. Hysteresis was not observable at 296 K, consistent with literature data. However, hysteresis in water content was observed at sub‐273 K. The lowest relative humidity (RH), at which hygroscopic growth of particles did not depend on exposure history to water vapor, was defined as threshold RH. Threshold RH for 100 nm particles was approximately the same as the glass transition points when hysteresis clearly happened, demonstrating that water diffusion in a highly viscous matrix of organic aerosols was the key to the phenomenon. Employment of a kinetic multi‐layer model quantitatively predicted threshold RH as a function of temperature, exposure time, and the particle size. Considering the temperature and RH range of Earth's atmosphere, we hypothesize that hysteresis in water content for organic aerosols ubiquitously occurs in the upper troposphere, impacting chemical aging and cloud formation processes.

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Divergent Impacts of Biomass Burning and Fossil Fuel Combustion Aerosols on Fog‐Cloud Microphysics and Chemistry: Novel Insights From Advanced Aerosol‐Fog Sampling

Cited by 5 publications

References 46 publications

The Impact of Agroecosystems on Nitrous Acid (HONO) Emissions during Spring and Autumn in the North China Plain

The Impact of Agroecosystems on Nitrous Acid (HONO) Emissions during Spring and Autumn in the North China Plain

Efficient Nitrate Formation in Fog Events Implicates Fog Interstitial Aerosols as Significant Drivers of Atmospheric Chemistry

Hysteresis in Water Content of Ultrafine Glassy Organic Aerosol Particles

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