Meteorological and chemical impacts on ozone formation: A case study in Hangzhou, China

Li, Kangwei; Fang, Ying; White, Stephen; Jang, Carey; Gao, Xiang; Hong, Sang-Bum; Shen, Jiandong; Azzi, Merched; Cen, Kefa

doi:10.1016/j.atmosres.2017.06.003

Cited by 135 publications

(44 citation statements)

References 48 publications

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“…The results showed distinctive temporal characteristics, whereby lower levels of SO 2 , CO, NO x , O 3 and VOCs were observed in July and August (midsummer) ( Table S6). These results were similar to those obtained for other urban areas worldwide (Cheng et al, 1997;Na et al, 2001;Li and Wang, 2012). Changes in PBL height, human activities and abundance of • OH were the potential causes for this phenomenon.…”

Section: Temporal Variationssupporting

confidence: 89%

“…Their contributions to the sum of OFP were within the range of 69.4 %-77.6 % (Table 5), with 61.3 %-76.5 % of total VOCs weighted by concentration, highlighting the importance of reduction of emissions of these VOCs, whether based on relative reactivity or mixing ratios. Additionally, it is worth noting that the percentage of acetylene (4.51±0.34 %) weighted by OFP was higher than many other areas in China, including Guangzhou (2.20 %) and the YRD (2.37 %) (Li and Wang, 2012;Jia et al, 2016), demonstrating that it is necessary to conduct emission controls on sources related to combustion (i.e., vehicle emissions and biofuel burning) in Zhengzhou.…”

Section: Relative Reactivity Of Vocsmentioning

confidence: 98%

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Characterization of VOCs and their related atmospheric processes in a central Chinese city during severe ozone pollution periods

Li¹,

Gong

et al. 2019

Atmos. Chem. Phys.

133

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Abstract. A 5-month campaign (from May to September 2017) was conducted to characterize volatile organic compounds (VOCs) for the first time at four sites in Zhengzhou, Henan Province, China, where ground level ozone (O3) concentration has shown an increasing trend in recent years. Canister samples were collected for the measurement of 57 VOCs, which, along with reactive nitrogen oxides (NOx), are the most important O3 precursors. During the same period, O3 and its precursor gases were monitored online simultaneously. The results indicated that the average mixing ratio of total quantified VOCs (ΣVOCs=28.8±22.1 ppbv) in Zhengzhou was lower than that in the other Chinese megacities, while alkyne comprised a higher proportion of ΣVOCs. The abundances, compositions and ratios of typical VOCs showed clear spatial and temporal variations. Cluster analysis indicates that air masses from the south of Zhengzhou were cleaner than from other directions. The molar ratio of VOCs to NOx indicated that, in general, O3 formation was more sensitive to VOCs than NOx formation in Zhengzhou. The source apportionment was conducted with positive matrix factorization (PMF), and it was found that vehicle exhaust, coal and biomass burning and solvent usage were the major sources for ambient VOCs at all four sites. From potential source contribution function (PSCF) analysis, the strong emissions from coal + biomass burning and solvent usage were concentrated in the southwest of Shanxi and Henan provinces. This study gathers scientific evidence on the pollution sources for Zhengzhou, benefiting the government to establish efficient environmental control measures, particularly for O3 pollution.

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Section: Temporal Variationssupporting

confidence: 89%

Section: Relative Reactivity Of Vocsmentioning

confidence: 98%

Characterization of VOCs and their related atmospheric processes in a central Chinese city during severe ozone pollution periods

Li¹,

Gong

et al. 2019

Atmos. Chem. Phys.

133

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“…Over the past few decades, ozone concentrations have been rising around the world [21,25]. With the rapid development of Chinese cities, ozone pollution is becoming more and more serious [26,27]. Since 2013, several serious air pollution phenomena have broken out in northeast China, and the environmental pollution has become increasingly serious [28,29].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Spatial–Temporal Variation of the Surface Ozone Concentration and Its Associated Meteorological Factors in Changchun

Fang

Wang

2019

Environments

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Ozone (O3) pollution has become one of the most challenging problems in China, and high O3 concentrations have been a major air quality issue in Changchun. Based on continuous observation data of surface ozone concentrations from ten automatic air monitoring stations and meteorological data from the meteorological bureau in Changchun, the temporal and spatial variations of the O3 concentration and its relationships with meteorological factors were analyzed by correlation analysis during the period of 2013–2017. The results showed the following: A single apex model of the annual mean O3 concentrations of the daily maximum 8 h average (MDA8) was found from the data for 2013 to 2017 in Changchun, with the highest MDA8 O3 concentrations in 2015 and a slight decline from then until 2017. The O3 concentrations in the suburban areas and the south of Changchun were higher than those downtown and north of the city. The seasonal variation of O3 concentrations was obvious, following the order summer > spring > autumn > winter, which was similar to the results of neighboring cities and provinces in Changchun. The days on which O3 concentrations exceeded the standard were concentrated in summer and spring, and the total number of ozone excess days was 91 days; the maximum number of ozone excess days was in 2015. The O3 concentration exceeded the standard in Changchun mainly in March–August, and its monthly mean value curve showed a bimodal type in which the highest values appeared in May and July, while the lowest values appeared in December. The diurnal pattern of ozone showed a single peak mode, and the peak value usually appeared at 14:00–16:00 while the minimum value appeared at 07:00–08:00. O3 concentrations in Changchun and the six selected pollutants CO, NO, NO2, NOx, PM10, and PM2.5 were negatively correlated. Higher temperature is a necessary synoptic condition for ozone pollution in Changchun: when the temperature rose, O3 concentrations increased significantly; further, O3 concentrations were negatively correlated with relative humidity and atmospheric pressure and were positively correlated with temperature and solar radiation. The O3 concentrations were highest when the wind scale approached 14~20 km/h and the wind direction was S. Combined with the research results in the surrounding areas of Changchun, it is indicated that there may be an ozone contribution from south of Changchun through long-range pollution transport and tropospheric subsidence.

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“…Our conclusion was generally in line with the contemporaneous study implemented by L. , who found that a VOC-limited regime accounted for 47 % of the ozone formation during the summer in Hangzhou and that the others are under a NO x -limited regime, taking BVOCs into consideration. Recently, Li et al (2017) also deduced that the summer ozone mostly presented a VOC-limited regime and a transition region alternately in the city of Hangzhou.…”

Section: Interspecies Correlationsmentioning

confidence: 99%

“…Subsequent studies at this site depicted the first picture of the seasonal variations of O 3 and its precursors . In the city of Hangzhou, only short-term measurements of O 3 were recently made during the summertime of 2013 (Li et al, 2017). Hence, there is a large knowledge gap concerning seasonal characteristics of these pollutants and a discrepancy in their origin; these are both crucial for fully understanding the complex combined pollution of PM 2.5 and O 3 in the city of Hangzhou.…”

Section: Introductionmentioning

confidence: 99%

Characterization of atmospheric trace gases and particulate matter in Hangzhou, China

Zhang

et al. 2018

Atmos. Chem. Phys.

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Abstract. The Yangtze River Delta (YRD) is one of the most densely populated regions in China with severe air quality issues that have not been fully understood. Thus, in this study, based on 1-year (2013) continuous measurement at a National Reference Climatological Station (NRCS, 30.22 • N, 120.17 • E; 41.7 m a.s.l.) in the center of Hangzhou in the YRD, we investigated the seasonal characteristics, interspecies relationships, and the local emissions and the regional potential source contributions of trace gases (including O 3 , NO x , NO y , SO 2 , and CO) and particulate matter (PM 2.5 and PM 10 ). Results revealed that severe two-tier air pollution (photochemical and haze pollution) occurred in this region, with frequent exceedances in O 3 (38 days) and PM 2.5 (62 days). O 3 and PM 2.5 both exhibited distinct seasonal variations with reversed patterns: O 3 reaching a maximum in warm seasons (May and July) but PM 2.5 reaching a maximum in cold seasons (November to January). The overall results from interspecies correlation indicated a strong local photochemistry favoring the O 3 production under a volatile organic compound (VOC)-limited regime, whereas it moved towards an optimum O 3 production zone during warm seasons, accompanied by the formation of secondary fine particulates under high O 3 . The emission maps of PM 2.5 , CO, NO x , and SO 2 demonstrated that local emissions were significant for these species on a seasonal scale. The contributions from the regional transport among inland cities (Zhejiang, Jiangsu, Anhui, and Jiangxi Province) on a seasonal scale were further confirmed to be crucial to air pollution at the NRCS site by using backward trajectory simulations. Air masses transported from the offshore areas of the Yellow Sea, East Sea, and South Sea were also found to be highly relevant to the elevated O 3 at the NRCS site through the analysis of potential source contribution function (PSCF). Case studies of photochemical pollution (O 3 ) and haze (PM 2.5 ) episodes both suggested the combined importance of local atmospheric photochemistry and synoptic conditions during the accumulation (related with anticyclones) and dilution process (related with cyclones). Apart from supplementing a general picture of the air pollution state in the city of Hangzhou in the YRD region, this study specifically elucidates the role of local emission and regional transport, and it interprets the physical and photochemical processes during haze and photochemical pollution episodes. Moreover, this work suggests that cross-regional control measures are crucial to improve air quality in the YRD region, and it further emphasizes the importance of local thermally induced circulation for air quality.

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Meteorological and chemical impacts on ozone formation: A case study in Hangzhou, China

Cited by 135 publications

References 48 publications

Characterization of VOCs and their related atmospheric processes in a central Chinese city during severe ozone pollution periods

Characterization of VOCs and their related atmospheric processes in a central Chinese city during severe ozone pollution periods

Analysis of the Spatial–Temporal Variation of the Surface Ozone Concentration and Its Associated Meteorological Factors in Changchun

Characterization of atmospheric trace gases and particulate matter in Hangzhou, China

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