The Relationship of PM Variation to Visibility and Mixing Layer Height under Haze/Fog Condition in Multi-Cities of Northeast China

Zhao, Huiling; Che, Huizheng; Ma, Yanjun; Wang, Yangfeng; Yang, Haiguang; Liu, Yuche; Wang, Yaqiang; Wang, Hong; Zhang, Xiaoye

doi:10.20944/preprints201703.0160.v1

Cited by 4 publications

(2 citation statements)

References 42 publications

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“…Meanwhile the vertical shear of horizontal wind between 850 hPa and 500 hPa shows a correlation coefficient of 0.33 with atmospheric visibility, and it slightly exceeds 0.05 confidence level. The higher wind speed or stronger vertical shear transport the pollutants outward, reduce the ground pollutants concentration and increase atmospheric visibility; while lower wind speed or weaker vertical shear with weaker transportation capacity make the pollutants accumulate near surface and decrease the atmospheric visibility [6].…”

Section: Dynamic Effectmentioning

confidence: 99%

“…With increasing pollution sources from rapid urbanization and massive industrial production, foggy haze events, which cause low atmospheric visibility [1] and are mainly caused by particle matter (PM) [2], are becoming more frequent and severe in North China [3][4]. This serious environmental problem is even worse when coal is used for heating during the winter seasons [5][6]. So that, we should do more study on foggy haze process to reduce these increasing air pollution events.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Meteorological conditions for severe foggy haze episodes over north China in 2016–2017 winter

Li¹,

Gao

Li³

et al. 2019

Atmospheric Environment

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Section: Dynamic Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Meteorological conditions for severe foggy haze episodes over north China in 2016–2017 winter

Li¹,

Gao

Li³

et al. 2019

Atmospheric Environment

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Detailed Assessment of the Effects of Meteorological Conditions on PM10 Concentrations in the Northeastern Part of the Czech Republic

Volná

Hladký

2020

Atmosphere

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This article assessed the links between PM10 pollution and meteorological conditions over the Czech-Polish border area at the Třinec-Kosmos and Věřňovice sites often burdened with high air pollution covering the years 2016–2019. For this purpose, the results of the measurements of special systems (ceilometers) that monitor the atmospheric boundary layer were used in the analysis. Meteorological conditions, including the mixing layer height (MLH), undoubtedly influence the air pollution level. Combinations of meteorological conditions and their influence on PM10 concentrations also vary, depending on the pollution sources of a certain area and the geographical conditions of the monitoring site. Gen1erally, the worst dispersion conditions for the PM10 air pollution level occur at low air temperatures, low wind speed, and low height of the mixing layer along with a wind direction from areas with a higher accumulation of pollution sources. The average PM10 concentrations at temperatures below 1 °C reach the highest values on the occurrence of a mixing layer height of up to 400 m at both sites. The influence of a rising height of the mixing layer at temperatures below 1 °C on the average PM10 concentrations at Třinec-Kosmos site is not as significant as in the case of Věřňovice, where a difference of several tens of µg·m−3 in the average PM10 concentrations was observed between levels of up to 200 m and levels of 200–300 m. The average PM10 hourly concentrations at Třinec-Kosmos were the highest at wind speeds of up to 0.5 m·s−1, at MLH levels of up to almost 600 m; at Věřňovice, the influence of wind speeds of up to 2 m·s−1 was detected. Despite the fact that the most frequent PM10 contributions come to the Třinec-Kosmos site from the SE direction, the average maximum concentration contributions come from the W–N sectors at low wind speeds and MLHs of up to 400 m. In Věřňovice, regardless of the prevailing SW wind direction, sources in the NE–E sector from the site have a crucial influence on the air pollution level caused by PM10.

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Characteristics of Turbulence and Aerosol Optical and Radiative Properties during Haze–Fog Episodes in Shenyang, Northeast China

Wang

et al. 2021

Atmosphere

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The characteristics of turbulence in the planetary boundary layer (PBL) and the aerosol optical and radiative properties during haze and haze–fog mixed episodes on 22–27 January 2021, in Shenyang, a provincial city in Northeast China, were analyzed using meteorological and aerosol observations. During the haze episode, the hourly mean PM2.5 concentration reached a maximum of 337 µg m−3 and visibility decreased to 1.6 km. The PM2.5 concentration decreased gradually during the haze–fog mixed episode as a result of the scavenging effects of fog, but visibility mostly remained below 1 km owing to high ambient relative humidity (>90%). During the haze–fog mixed episode, an increasing proportion of PM2.5 led to a higher ratio of the backward to the total scattering coefficient. As fog occurred, downward shortwave radiation arriving at the surface was significantly reduced, and upward longwave radiation increased and almost equaled the downward longwave radiation, which can be used as a good indicator for distinguishing haze and fog. Mechanical turbulence was weak during both episodes, and latent heat flux varied within a wider range during the haze–fog mixed episode. The PBL dynamic structure affected the vertical distribution of aerosols/fog droplets. Aerosol-rich layers appeared at altitudes below 0.5 km and above 0.6 km during the haze episode. The elevated aerosol layer was related to the aerosol transport from upstream polluted areas caused by strong upper-level turbulence, and it began to mix vertically after sunrise because of convective turbulence. Aerosols and fog droplets were mostly trapped in a shallower PBL with a height of 0.2–0.4 km during the haze–fog mixed episode because of weaker turbulence.

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The Relationship of PM Variation to Visibility and Mixing Layer Height under Haze/Fog Condition in Multi-Cities of Northeast China

Cited by 4 publications

References 42 publications

Meteorological conditions for severe foggy haze episodes over north China in 2016–2017 winter

Meteorological conditions for severe foggy haze episodes over north China in 2016–2017 winter

Detailed Assessment of the Effects of Meteorological Conditions on PM10 Concentrations in the Northeastern Part of the Czech Republic

Characteristics of Turbulence and Aerosol Optical and Radiative Properties during Haze–Fog Episodes in Shenyang, Northeast China

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