Meteorological Variables and Synoptic Patterns Associated with Air Pollutions in Eastern China during 2013–2018

Abstract

Steady meteorological conditions are important external factors affecting air pollution. In order to analyze how adverse meteorological variables affect air pollution, surface synoptic situation patterns and meteorological conditions during heavy pollution episodes are discussed. The results showed that there were 78 RPHPDs (regional PM 2.5 pollution days) in Jiangsu, with a decreasing trend year by year. Winter had the most stable meteorological conditions, thus most RPHPDs appeared in winter, followed by autumn and summer, with the least days in spring. RPHPDs were classified into three patterns, respectively, as equalized pressure (EQP), advancing edge of a cold front (ACF) and inverted trough of low pressure (INT) according to the SLP (sea level pressure). RPHPDs under EQP were the most (51%), followed by ACF (37%); INT was the minimum (12%). Using statistical methods and meteorological condition data on RPHPDs from 2013 to 2017 to deduce the thresholds and 2018 as an independent dataset to validate the proposed thresholds, the threshold values of meteorological elements are summarized as follows. The probability of RPHPDs without rain was above 92% with the daily and hourly precipitation of all RPHPDs below 2.1 mm and 0.8 mm. Wind speed, RHs, inversion intensity(ITI), height difference in the temperature inversion(ITK), the lower height of temperature inversion (LHTI) and mixed-layer height (MLH) in terms of 25%-75% high probability range were respectively within 0.5-3.6 m s −1 , 55%-92%, 0.7-4.0 • C 100 m −1 , 42-576 m, 3-570 m, 200-1200 m. Two conditions should be considered: whether the pattern was EQP, ACF or INT and whether the eight meteorological elements are within the thresholds. If both criteria are met, PM 2.5 particles tend to accumulate and air pollution diffusion conditions are poor. Unfavorable meteorological conditions are the necessary, but not sufficient condition for RPHPDs.

Key Points in Air Pollution Meteorology

“…Dai et al [ 20 ] used a classification method for regional particulate pollution days in Eastern China based on a subjective approach that employs only three patterns: equalised pressure (EQP), the advancing edge of a cold front (ACF), and the inverted trough of low pressure (INT). The seasonal features of these patterns were also considered to form eight types, three EQPs (in summer, autumn, and winter), two ACFs (in autumn and winter), and three INTs (in spring, autumn, and winter).…”

Evolution of Urban Haze in Greater Bangkok and Association with Local Meteorological and Synoptic Characteristics during Two Recent Haze Episodes

“…A single inversion layer is given as all successive vertical levels from the sounding with temperature monotonically increasing with height. Inversion intensity ( IV ) is a simple parameter used to indicate the extent of difficulty or blockage to which air pollutants penetrate an inversion layer, which was here computed as the rate of temperature change (°C per 100 m depth) from the bottom to the top of the inversion layer, similar to Dai et al (2020) [ 7 ]. Only inversion layers with IV > 0.1 °C per 100 m were considered.…”

“…Haze pollution has been studied globally to understand its formation and evolution mechanism [ 4 , 5 , 6 , 7 ], potentials sources contribution [ 5 , 8 , 9 ], mitigation strategies [ 10 , 11 ], and early warning or forecasting [ 12 ]. A haze episode may be induced by one or a number of factors combined, which encompasses emissions, secondary aerosols [ 13 , 14 , 15 , 16 , 17 ], and atmospheric transport [ 8 , 17 ], with unfavorable weather conditions acting as an accelerating factor [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

A Movable Fog-Haze Boundary Layer Conceptual Model Over Jianghuai Area, China

“…Local emissions, pollutants transported from the North China Plain, and boundary layer change can all affect the intensity and duration of the fog-haze episode (Liang et al, 2017;Wang et al, 2016;Yu et al, 2016). The atmosphere boundary layer conditions in the Jianghuai area, which covers Jiangsu and Anhui provinces in this article, can affect not only local pollutant concentration but also pollutant transportation between North China and the Yangtze River Delta (Dai et al, 2020;Gu et al, 2020;Liu et al, 2018a;Liu et al, 2018b;Peng et al, 2016;Shen et al, 2021a;Shen et al, 2021b;Xie et al, 2021;Zhou et al, 2021).…”

“…Regional air quality is a rising concern in East China in recent years, many severe air pollutions were recorded in East China (Dai et al, 2020;Gu et al, 2020;Shi et al, 2020;Sun et al, 2020;Wang et al, 2021), Beijing-Tianjin-Hebei region (Liu et al, 2019a;Li et al, 2019Li et al, , 2020Lv et al, 2020) and the Pearl River Delta (Wu et al, 2013;Li et al, 2018;Dai et al, 2019), due to rapid developments of economy and urbanization in these regions. The rapid and varied industrial development, the use of coal for power generation, and the increasing number of vehicles on the roads have increased the emission of pollutants in the region, especially particulate matter (PM) and its precursors.…”