Exploring the regional pollution characteristics and meteorological formation mechanism of PM2.5 in North China during 2013–2017

Li, Mingge; Wang, Lili; Liu, Jingda; Gao, Wenkang; Song, Tao; Sun, Yifei; Li, Liang; Li, Xingru; Wang, Yonghong; Liu, Huan; Daellenbach, Kaspar R.; Paasonen, Pauli; Kerminen, Veli‐Matti; Kulmala, Markku; Wang, Yuesi

doi:10.1016/j.envint.2019.105283

Cited by 87 publications

(56 citation statements)

References 46 publications

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“…It was consistent with the results of Li et al (2020) on the relationship between pollutant concentration and circulation types in northern China. Weather types with high PM2.5 concentration but occurring no more than ten times, such as type CE and type CW, were not discussed in this article.…”

Section: The Typical Weather Types and Pm25 Distributionsupporting

confidence: 91%

“…The pollution intensity is closely related to the large-scale weather circulations. Although the dominant synoptic patterns in different seasons vary greatly, the modulating effects on air pollution of specific circulation types in different seasons are similar (Liao et al, 2017;Li et al, 2020). The spatial distribution of PM2.5 in Beijing under pollution types C, SW, W and clean type A is shown in Fig.…”

Section: The Typical Weather Types and Pm25 Distributionmentioning

confidence: 97%

“…They also found that synoptic patterns with high-pressure systems located to the east or southeast of Beijing are the most favorable types for heavy aerosol pollution events. Li et al (2020) quantitatively analyzed the contributions of different large-scale circulations on PM2.5.…”

Section: Introductionmentioning

confidence: 99%

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The dynamic-thermal structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing

Jiang¹,

Xin²,

Wang³

et al. 2020

Preprint

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Abstract. Synoptic circulations play important roles in meteorological conditions and air quality within the planetary boundary layer (PBL). Based on Lamb-Jenkinson weather typing and multiple field measurements, this study reveals the mechanism of how the coupling effects of multiscale circulations influence PBL structure and pollution. Due to the topographic blocking in the daytime, pollutants accumulate in the plain areas horizontally. The sinking divergent flows overlying on the rising convergent flows within the PBL inhibit the continuously upward dispersion of aerosols vertically. At night, the horizontal and vertical coupling mechanisms synergistically worsen the pollution. The large-scale environmental winds and regional-scale breezes affect the pollution directly via the horizontal coupling effect, which generates a pollution convergent zone of different directional flows. The relative strength of flows causes the severely polluted area to move around horizontally from 39° N to 41° N. In addition, the multiscale circulations regulate the mixing and diffusion of pollutants indirectly via the vertical coupling effect, which changes the PBL dynamic-thermal structure. The warm advection transported by the upper environmental winds overlies the cold advection transported by the lower regional breezes, generating strong wind direction shear and advective inversion. The capping inversion and the convergent sinking motion within the PBL suppress massive pollutants below the zero speed zone. The multilayer PBL under cyclonic circulation has no diurnal variation. Weak ambient winds strengthen the mountain breezes observably at night, the temperature inversion can reach 900 m. The nocturnal shallower PBL, consistent with the zero velocity zone between ambient and mountain winds, can reach 600 m. By contrast, the PBL under southwesterly circulation is a mono-layer with obvious diurnal variation, reaching 2000 m in the daytime. The strong winds circulations restrain the development of regional breezes, the zero speed zone is located at 400 m and the inversion is lower than 200 m at night. The PBL under westerly circulation has a hybrid structure with both multiple aerosol layers and diurnal variation. The inversion is generated by the vertical shear of zonal winds. Clean and strong north winds are dominated under anticyclone circulation, the vertical shear and the diurnal variation of thermal field disappear because of strong turbulent mixing, and there is no significant PBL structure. Our results imply that the algorithm of atmospheric environmental capacity under synoptic circulations, such as the cyclonic type, with a multilayer PBL needs to be improved.

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Section: The Typical Weather Types and Pm25 Distributionsupporting

confidence: 91%

Section: The Typical Weather Types and Pm25 Distributionmentioning

confidence: 97%

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The dynamic-thermal structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing

Jiang¹,

Xin²,

Wang³

et al. 2020

Preprint

Self Cite

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“…A significant impact of COVID-19 lockdown on air quality improvement was found in all 4 countries and the Northern region of Italy, including a significant decrease in NO 2 concentration (see Figures 4-8). Previous studies conclude the significance of the effect of emissions resulting from road and air transportation when it comes to the atmospheric concentration of the NO2 pollutant [20,59,73]. Recent studies of Tian et al [35] analysis results concerning city air pollution changes in Canada during the pandemic imply that air quality improvement correlates with national lockdown policy.…”

Section: Discussionmentioning

confidence: 99%

COVID-19 and Air Pollution: Measuring Pandemic Impact to Air Quality in Five European Countries

Skirienė

Stasiškienė

2021

Atmosphere

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The rapid spread of the coronavirus (COVID-19) pandemic affected the economy, trade, transport, health care, social services, and other sectors. To control the rapid dispersion of the virus, most countries imposed national lockdowns and social distancing policies. This led to reduced industrial, commercial, and human activities, followed by lower air pollution emissions, which caused air quality improvement. Air pollution monitoring data from the European Environment Agency (EEA) datasets were used to investigate how lockdown policies affected air quality changes in the period before and during the COVID-19 lockdown, comparing to the same periods in 2018 and 2019, along with an assessment of the Index of Production variation impact to air pollution changes during the pandemic in 2020. Analysis results show that industrial and mobility activities were lower in the period of the lockdown along with the reduced selected pollutant NO2, PM2.5, PM10 emissions by approximately 20–40% in 2020.

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“…The daily mean PM2.5 concentration violated the standard (35 g m -3 ) by 33% and 9% of the entire period in Seoul and Aewol, respectively. Despite the difference in PM2.5 level, the seasonal variation was similar at the two sites with high levels in the cold months, demonstrating the enhancement of wintertime PM2.5 is a significant regional issue over the east Asia (Fan et al, 2020;Li et al, 2020;Liu et al, 2018).…”

Section: The Characteristic Variation Of Pm25 Concentrationmentioning

confidence: 96%

Physical and chemical constraints on transformation and mass-increase of fine aerosols in northeast Asia

Lim

Lee

Laj

et al. 2021

Preprint

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Abstract. Over the past few decades, northeast Asia has suffered from the extreme levels of PM2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 μm). Despite extensive efforts and the scientific advances in understanding PM2.5 pollution, the fundamental mechanisms responsible for the occurrence of high PM2.5 concentrations have not been comprehensively understood. In this study, we investigated the physical and chemical drivers for the formation and transformation of atmospheric particles using a four-year dataset of nanoparticle number size distributions, PM2.5 chemical composition, gaseous precursors, and meteorological variables in northeast Asia outflows. The empirical orthogonal function (EOF) analyses of size-separated particle numbers extracted two modes representing a burst of nanoparticles (EOF1) and an increase in PM2.5 mass (EOF2) associated with persistent anticyclone and synoptic-scale stagnation, respectively. The vertical structure of the particles demonstrated that the synoptic conditions also affected the daily evolution of boundary layer, promoting either the formation of nanoparticles through deep mixing or conversion into accumulation-mode particles in shallow mixed layers. In the haze-development episode equivalent to EOF2 during the KORUS-AQ (KORea-US Air Quality) campaign, the PM2.5 mass reached 63 μg m−3 with the highest contribution from inorganic constituents, which was accompanied by a thick coating of refractory black carbon (rBC) that linearly increased with condensation-mode particles. This observational evidence suggests that the thick coating of rBC resulted from an active conversion of condensable gases into particle-phase on the BC surface, thereby increasing the mass of the accumulation-mode aerosol. Consequently, this result complies with the strategy to reduce black carbon as a way to effectively mitigate haze pollution as well as climate change in northeast Asia.

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Exploring the regional pollution characteristics and meteorological formation mechanism of PM2.5 in North China during 2013–2017

Cited by 87 publications

References 46 publications

The dynamic-thermal structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing

The dynamic-thermal structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing

COVID-19 and Air Pollution: Measuring Pandemic Impact to Air Quality in Five European Countries

Physical and chemical constraints on transformation and mass-increase of fine aerosols in northeast Asia

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