The air pollution governed by subtropical high in a coastal city in Southeast China: Formation processes and influencing mechanisms

Wu, Xin; Xu, Lingling; Hong, Youwei; Chen, Jinfang; Qiu, Yuqing; Hu, Bo‐Ping; Zhang, Hong; Zhang, Yanru; Liu, Taotao; Yan-tin, Chen; Bian, Yahui; Guo, Zhao; Chen, Jinsheng; Li, Mengren

doi:10.1016/j.scitotenv.2019.07.341

Cited by 36 publications

(18 citation statements)

References 35 publications

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“…Due to the Rtran in the afternoon, the daily maximum O3 values appeared at around 17:00 LT. However, the maximum daily value of O3 at this observation site generally appeared at around 15:00 LT without regional transport (Wu et al, 2019). Under the conditions of southeast wind direction, downtown area with high density vehicles would make O3 and its precursors transmitting to our observation site, consistent with the diurnal patterns of NO2, OVOCs, alkanes, and aromatic in the early morning and afternoon (Fig.…”

Section: Radical Chemistrysupporting

confidence: 80%

Atmospheric oxidation capacity and ozone pollution mechanism in a coastal city of Southeast China: Analysis of a typical photochemical episode by Observation-Based Model

Liu

Hong

et al. 2021

Preprint

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Abstract. A typical multi-day ozone (O3) pollution event was chosen to explore the atmospheric oxidation capacity (AOC), OH reactivity, radical chemistry, and O3 pollution mechanism in a coastal city of Southeast China, with an Observation-Based Model coupled to the Master Chemical Mechanism (OBM-MCM). The hydroxyl radical (OH) was the predominant oxidant (91±23 %) for daytime AOC, while NO3 radical played an important role for AOC during the nighttime (64±11 %). Oxygenated volatile organic compounds (OVOCs, 30±8 %), NO2 (29±8 %) and CO (25±5 %) were the dominant contributors to OH reactivity, accelerating the production of O3 and recycling of ROx radicals (ROx=OH+HO2+RO2). Photolysis of nitrous acid (HONO, 33±14 %), O3 (25±13 %), formaldehyde (HCHO, 20±5 %), and other OVOCs (17±2 %) were the important primary sources of ROx radicals, which played initiation roles in atmospheric oxidation processes. O3 formation was VOC-sensitive, and controlling emissions of aromatics, alkenes, and long-chain alkanes were benefit for ozone pollution mitigation. Combined with regional transport analysis, the reasons for this O3 episode were the accumulation of local photochemical production and regional transport. The results of sensitivity analysis showed that VOCs were the limiting factor of radical recycling and O3 formation, and the 5 % reduction of O3 would be achieved by decreasing 20 % anthropogenic VOCs. The findings of this study have significant guidance for emission reduction and regional collaboration on future photochemical pollution control in the relatively clean coastal cities of China and similar countries.

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Section: Radical Chemistrysupporting

confidence: 80%

Atmospheric oxidation capacity and ozone pollution mechanism in a coastal city of Southeast China: Analysis of a typical photochemical episode by Observation-Based Model

Liu

Hong

et al. 2021

Preprint

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“…Sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) had been frequently used in previous studies to measure the degrees of oxidation of sulfur and nitrogen [27,35,52]. Higher SOR and NOR values could indicate a larger proportion of sulfate and nitrate formed by the secondary chemical reactions [53]. Thus, we calculated the values of the sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) in four seasons for further investigating the transformation of SO 2 to sulfate and NO 2 to nitrate, respectively [53]:…”

Section: Formations Of Secondary Aerosolsmentioning

confidence: 99%

“…Higher SOR and NOR values could indicate a larger proportion of sulfate and nitrate formed by the secondary chemical reactions [53]. Thus, we calculated the values of the sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) in four seasons for further investigating the transformation of SO 2 to sulfate and NO 2 to nitrate, respectively [53]:…”

Section: Formations Of Secondary Aerosolsmentioning

confidence: 99%

Dominant Contributions of Secondary Aerosols and Vehicle Emissions to Water-Soluble Inorganic Ions of PM2.5 in an Urban Site in the Metropolitan Hangzhou, China

Chun

Xue

et al. 2021

Atmosphere

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Water soluble inorganic ions (WSIIs) are important components in PM2.5 and could strongly affect the acidity and hygroscopicity of PM2.5. In order to achieve the seasonal characteristics and determine the potential sources of WSIIs in PM2.5 in Hangzhou, online systems were used to measure hourly mass concentrations of WSIIs (SO42−, NO3−, NH4+, Cl−, Na+, K+, Ca2+ and Mg2+) as well as PM2.5, NO2 and SO2 at an urban site for one month each season (May, August, October, December) in 2017. Results showed that the hourly mass concentrations of PM2.5 during the whole campaign varied from 1 to 292 μg·m−3 with the mean of 56.03 μg·m−3. The mean mass concentration of WSIIs was 26.49 ± 20.78 μg·m−3, which contributed 48.28% to averaged PM2.5 mass. SNA (SO42−, NO3− and NH4+) were the most abundant ions in PM2.5 and on average, they comprised 41.57% of PM2.5 mass. PM2.5, NO2, SO2 and WSIIs showed higher mass concentrations in December, possibly due to higher energy consumption emissions, unfavorable meteorological factors (e.g., lower wind speed and temperature) and regional transport. Results from PCA models showed that secondary aerosols and vehicle emissions were the dominant sources of WSIIs in the observations. Our findings highlight the importance of stronger controls on precursor (e.g., SO2 and NO2) emissions in Hangzhou, and show that industrial areas should be controlled at local and regional scales in the future.

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“…First, higher humidity causes PM 2.5 to adsorb more water vapor, which contributes to the accumulation of toxic substances and significantly increases the mass concentration of PM 2.5 [42]. Second, high humidity promotes the gas-to-particle distribution, increasing the content of hygroscopic components, especially ammonium nitrate; thus, further increasing the absorption of water and the mass concentration of PM 2.5 [43]. The mass concentration of PM 2.5 and T were found to be significantly negatively correlated (R = −0.691, p < 0.01); T and TD 30 values of the whole samples and the water-soluble fractions showed a significant negative correlation.…”

Section: Relationship Between the Td 30 Values Pm 25 Mass Concentrations And Meteorological Conditionsmentioning

confidence: 99%

Variation of Particle-Induced Oxidative Potential of PM2.5 in Xinjiang, NW-China

Talifu

Ding

et al. 2021

Atmosphere

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In order to evaluate the toxicity of PM2.5 in the Dushanzi area, PM2.5 samples were collected from December 2015 to July 2016, and a plasmid DNA damage assessment method was used to analyze the variation in the oxidative damage ability and its relationship with sampling conditions and toxic components (polycyclic aromatic hydrocarbons, and heavy metals) loaded on the surface of PM2.5. The results showed that the TD30 values (toxic dosage of PM2.5 causing 30% of plasmid DNA damage) of both the whole samples and the water-soluble fractions were lower during the heating period (369 μg/mL and 536 μg/mL, respectively), but higher in the dust period and non-heating period (681 μg/mL and 498 μg/mL, respectively; and 804 μg/mL and 847 μg/mL, respectively). Studies on the effect of meteorological parameters showed an increasing trend in TD30 values for the whole samples and the water-soluble fractions as relative humidity, temperature and wind speed decrease. TD30 values for the whole samples and the water-soluble fractions were negatively correlated with Flu (r = −0.690,r = −0.668; p < 0.05), Flt (r =−0.671, r = −0.760; p < 0.05), BaP (r = −0.672, r = −0.725; p < 0.05), IcdP (r = −0.694, r = −0.740; p < 0.05), Pyr (r = −0.727, r = −0.768; p < 0.01) and BghiP (r = −0.874, r = −0.845; p < 0.01) during the heating period, while As (r = 0.792, r = 0.749; p < 0.05) and Sr (r = 0.776, r = 0.754; p < 0.05) during the dust period showed significant positive correlation. In addition, the TD30 values of PM2.5 collected during sand blowing weather was the highest (1458 μg/mL and 1750 μg/mL), while the average TD30 value of PM2.5 collected on hazy days were the lowest (419.8 μg/mL and 488.6 μg/mL). Particles collected on the first day after snowfall showed a lower oxidizing capacity (676 μg/mL and 1330 μg/mL). The characteristic TD30 values combined with back trajectory analysis indicated that hazy days were heavily influenced by air masses originating from the southern continent and local emissions, whereas the sand blowing weather came from the north of the Taklimakan Desert.

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The air pollution governed by subtropical high in a coastal city in Southeast China: Formation processes and influencing mechanisms

Cited by 36 publications

References 35 publications

Atmospheric oxidation capacity and ozone pollution mechanism in a coastal city of Southeast China: Analysis of a typical photochemical episode by Observation-Based Model

Atmospheric oxidation capacity and ozone pollution mechanism in a coastal city of Southeast China: Analysis of a typical photochemical episode by Observation-Based Model

Dominant Contributions of Secondary Aerosols and Vehicle Emissions to Water-Soluble Inorganic Ions of PM2.5 in an Urban Site in the Metropolitan Hangzhou, China

Variation of Particle-Induced Oxidative Potential of PM2.5 in Xinjiang, NW-China

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