Characteristics and formation mechanism of a winter haze–fog episode in Tianjin, China

Si, Han; Wu, Jianhui; Zhang, Yufen; Cai, Zhiqiang; Feng, Yinchang; Yao, Qing; Li, Xiangjin; Liu, Yiwei; Zhang, Min

doi:10.1016/j.atmosenv.2014.08.078

Cited by 93 publications

(49 citation statements)

References 32 publications

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“…These values were comparable to that observed in Nanjing where the average PM 2.5 was 175.6 µg m −3 , but were slightly higher than those in some other cities in the YRD, where mean values were generally lower than 147.3 µg m −3 when haze occurred in January 2013 (Wang et al, 2014a;. The aerosol pollution which happened in northeastern regions of China such as in Beijing, Tianjin, and Shijiazhuang was much more severe; for instance, the daily and hourly concentrations of PM 2.5 were up to 368 and 462 µg m −3 in Tianjin in 9 to 13 January 2013, and the maximum hourly value of approximately 1000 µg m −3 was recorded in Beijing and Shijiazhuang in January 2013 Han et al, 2014;Wang et al, 2015). Approximately 40 % of the time in January 2013, haze weather criteria were met, whereas no haze appeared in December 2012.…”

Section: General Characteristics Of Haze Eventsmentioning

confidence: 97%

“…The stagnant air, due to low wind speed and pressure, was unfavorable for aerosol horizontal transport or vertical diffusion, and therefore resulted in aerosol accumulation. Therefore, unfavorable weather conditions (high RH, and low rainfall, wind speed and atmospheric pressure) were among the causes forming haze in January 2013 in Suzhou as well as in many other cities (Wang et al, 2014b;Han et al, 2014;Yang et al, 2015).…”

Section: General Characteristics Of Haze Eventsmentioning

confidence: 99%

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Characteristics of aerosol pollution during heavy haze events in Suzhou, China

et al. 2016

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Abstract. Extremely severe haze weather events occurred in many cities in China, especially in the east part of the country, in January 2013. Comprehensive measurements including hourly concentrations of PM 2.5 and its major chemical components (water-soluble inorganic ions, organic carbon (OC), and elemental carbon (EC)) and related gas-phase precursors were conducted via an online monitoring system in Suzhou, a medium-sized city in Jiangsu province, just east of Shanghai. PM 2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less) frequently exceeded 150 µg m −3 on hazy days, with the maximum reaching 324 µg m −3 on 14 January 2013. Unfavorable weather conditions (high relative humidity (RH), and low rainfall, wind speed, and atmospheric pressure) were conducive to haze formation. High concentrations of secondary aerosol species (including SO 2− 4 , NO − 3 , NH + 4 , and SOC) and gaseous precursors were observed during the first two haze events, while elevated primary carbonaceous species emissions were found during the third haze period, pointing to different haze formation mechanisms. Organic matter (OM), (NH 4 ) 2 SO 4 , and NH 4 NO 3 were found to be the major contributors to visibility impairment. High concentrations of sulfate and nitrate might be explained by homogeneous gas-phase reactions under low RH conditions and by heterogeneous processes under relatively high RH conditions. Analysis of air mass trajectory clustering and potential source contribution function showed that aerosol pollution in the studied areas was mainly caused by local activities and surrounding sources transported from nearby cities.

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Section: General Characteristics Of Haze Eventsmentioning

confidence: 97%

Section: General Characteristics Of Haze Eventsmentioning

confidence: 99%

Characteristics of aerosol pollution during heavy haze events in Suzhou, China

et al. 2016

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“…SO 2 and NO 2 ) (Fig. 5), unfavourable meteorological conditions (Table 1), and frequent hazy events during these periods, when there were significant secondary reactions (Han et al, 2014;. In addition, it also illustrated that the discharge of atmospheric pollutants might still be enormous even under such strict control measures.…”

Section: Variations In Pm 25 Source Contributionsmentioning

confidence: 99%

“…As a consequence of rapid industrialization and urbanization, China has been suffering from air quality degradation in recent years (Zhao et al, 2011;Fu et al, 2014;Han et al, 2014;Gao et al, 2015;Hao et al, 2017). Frequently occurring severe haze is characterized by long duration, extensive coverage, and sharply increasing particulate concentration (Tao et al, 2014;Jiang and Xia, 2017).…”

Section: Introductionmentioning

confidence: 99%

Effectiveness evaluation of temporary emission control action in 2016 in winter in Shijiazhuang, China

et al. 2018

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Abstract. To evaluate the environmental effectiveness of the control measures for atmospheric pollution in Shijiazhuang, China, a large-scale controlling experiment for emission sources of atmospheric pollutants (i.e. a temporary emission control action, TECA) was designed and implemented during 1 November 2016 to 9 January 2017. Compared to the no-control action and heating period (NCAHP), under unfavourable meteorological conditions, the mean concentrations of PM 2.5 , PM 10 , SO 2 , NO 2 , and chemical species (Si, Al, Ca 2+ , Mg 2+ ) in PM 2.5 during the control action and heating period (CAHP) still decreased by 8, 8, 5, 19, 30.3, 4.5, 47.0, and 45.2 %, respectively, indicating that the control measures for atmospheric pollution were effective. The effects of control measures in suburbs were better than those in urban area, especially for the control effects of particulate matter sources. The control effects for emission sources of carbon monoxide (CO) were not apparent during the TECA period, especially in suburbs, likely due to the increasing usage of domestic coal in suburbs along with the temperature decreasing.The results of positive matrix factorization (PMF) analysis showed that crustal dust, secondary sources, vehicle emissions, coal combustion and industrial emissions were main PM 2.5 sources. Compared to the whole year (WY) and the no-control action and no-heating period (NCANHP), the contribution concentrations and proportions of coal combustion to PM 2.5 increased significantly during other stages of the TECA period. The contribution concentrations and proportions of crustal dust and vehicle emissions to PM 2.5 decreased noticeably during the CAHP compared to other stages of the TECA period. The contribution concentrations and proportions of industrial emissions to PM 2.5 during the CAHP decreased noticeably compared to the NCAHP. The pollutants' emission sources during the CAHP were in effective control, especially for crustal dust and vehicles. However, the necessary coal heating for the cold winter and the unfavourable meteorological conditions had an offset effect on the control measures for emission sources to some degree. The results also illustrated that the discharge of pollutants might still be enormous even under such strict control measures.

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“…Bei et al: Typical synoptic situations and their impacts on wintertime air pollution 2014; Guo et al, 2014;Han et al, 2014;Zhang et al, 2015;Yang et al, 2015). Guanzhong basin is located in the northwest of China, nestled between the Qinling Mountains in the south and the Loess Plateau in the north.…”

mentioning

confidence: 99%

Typical synoptic situations and their impacts on the wintertime air pollution in the Guanzhong basin, China

Bei

Huang

et al. 2016

Atmos. Chem. Phys.

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Abstract. Rapid industrialization and urbanization have caused severe air pollution in the Guanzhong basin, northwestern China, with heavy haze events occurring frequently in recent winters. Using the NCEP reanalysis data, the large-scale synoptic situations influencing the Guanzhong basin during wintertime of 2013 are categorized into six types to evaluate the contribution of synoptic situations to the air pollution, including "north-low", "southwesttrough", "southeast-high", "transition", "southeast-trough", and "inland-high". The FLEXPART model has been utilized to demonstrate the corresponding pollutant transport patterns for the typical synoptic situations in the basin. Except for "southwest-trough" and "southeast-high" (defined as favorable synoptic situations), the other four synoptic conditions (defined as unfavorable synoptic situations) generally facilitate the accumulation of air pollutants, causing heavy air pollution in the basin. In association with the measurement of PM 2.5 (particulate matter with aerodynamic diameter less than 2.5 µm) in the basin, the unfavorable synoptic situations correspond to high PM 2.5 mass concentrations or poor air quality and vice versa. The same analysis has also been applied to winters of 2008-2012, which shows that the basin was mainly influenced by the unfavorable synoptic situations during wintertime leading to poor air quality. The WRF-CHEM model has further been applied to simulate the selected 6 days representing the typical synoptic situations during the wintertime of 2013, and the results generally show a good agreement between the modeled distributions and variations of PM 2.5 and the corresponding synoptic situations, demonstrating reasonable classification for the synoptic situations in the basin. Detailed meteorological conditions, such as temperature inversion, low-level horizontal wind speed, and planetary boundary layer, all contribute to heavy air pollution events in the basin under unfavorable synoptic conditions. Considering the proportion of occurrence of unfavorable synoptic situations during wintertime, reduction of emissions is the optimum approach to mitigate the air pollution in the Guanzhong basin.

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Characteristics and formation mechanism of a winter haze–fog episode in Tianjin, China

Cited by 93 publications

References 32 publications

Characteristics of aerosol pollution during heavy haze events in Suzhou, China

Characteristics of aerosol pollution during heavy haze events in Suzhou, China

Effectiveness evaluation of temporary emission control action in 2016 in winter in Shijiazhuang, China

Typical synoptic situations and their impacts on the wintertime air pollution in the Guanzhong basin, China

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