Impact of control measures and typhoon weather on characteristics and formation of PM2.5 during the 2016 G20 summit in China
Graphical abstract
Introduction
Atmospheric PM2.5 (particulate matter with a dynamic equivalent diameter less than 2.5 μm) pollution is influenced by many factors. Fine particles can be directly released into the atmosphere by anthropogenic and natural activities. They can be subsequently transformed from primary pollutants (such as sulphur dioxide (SO2) and nitrogen oxides (NOX)) (Gard et al., 1998; George et al., 2015; Zhang et al., 2015). Huang et al. (2012) presented three typical kinds of air pollution in Shanghai: secondary pollution episode, dust pollution episode, and biomass combustion pollution episode with PM2.5 dominated by secondary aerosols, minerals, and K+ and carbonaceous aerosol, respectively. Fu et al. (2008) and Wang et al. (2006) determined that the heterogeneous reactions from SO2 and NO2 to SO42− and NO3− plays an important role in the formation of PM2.5. Except for the chemical factors, previous studies have also reported on the conducive effects of regional transport, relative humidity (RH), and stagnant meteorological conditions on the formation of PM2.5 (Wang et al., 2018; Li et al., 2017b). Overall, the formation mechanism of PM2.5 in the atmosphere is related to the emission sources, meteorological conditions, and transport of pollutants (Sun et al., 2006; Fu et al., 2008; Huang et al., 2012; Li et al., 2015; Zhang et al., 2015; Hua et al., 2016; Han et al., 2016a).
China is still under tremendous threat of PM2.5 pollution (Huang et al., 2012; Ming et al., 2017). The Chinese government has implemented the “Atmospheric Pollution Prevention and Control Action” in recent years with the aim of relieving air pollution in China. Moreover, the effects of the control measures on the reduction of pollution have been obvious during major events such as the Beijing 2008 Olympic Games, the 2014 Asia-Pacific Economic Cooperation (APEC) summit, and the China Victory Day Parade (V-Day Parade) in 2015 (Sun et al., 2016; Xu et al., 2017; Liang et al., 2017). A series studies have been conducted on the major species (element, water-soluble ions, and BC) of PM during the 2008 Olympic Games, and the results showed that the emission mitigation measures had successful reduction for the pollutants (Schleicher et al., 2011, 2012; Li et al., 2012). The obvious reduction of PM2.5 composition also found under the strict emission control of the V-Day Parade in 2015 comparing to the same period of a few years earlier (Han et al., 2016b). Although the emission restriction policy resulted in the suppression of PM, some secondary pollution episodes formed via the photochemical reaction and regional transport still could happen. In the early control period of the Olympic Games, a vehicle emissions and coal combustion were achieved, but the formation of secondary aerosol in regional scales still increased (Sun et al., 2011, 2016; Wang et al., 2010).
As for the possibilities of the pollution episodes even under the emission control period, it is important to understand the formation mechanism of PM2.5 to better regulate air quality. However, some special weather conditions also have a significant impact on the formation and mitigation of pollutants (Yan et al., 2016; Wang et al., 2005a). For example, typhoons are the predominant weather conditions during the summer monsoon season in East Asian. Fang et al. (2009) determined that typhoons re-suspended dust and caused an increase of particles (Fang et al., 2009). Meanwhile, the special meteorological conditions caused by a typhoon such as heavy rainfall and active atmospheric movement, could decrease atmospheric pollutants and affect the formation mechanism of PM2.5 (Yan et al., 2016; Fang et al., 2009). Control measures and typhoon both significantly reduce the concentration of atmospheric primary pollutants. Nevertheless, there are few comparative studies on the roles they play in the formation mechanism of PM2.5.
The 2016 G20 summit was held on 4–5 September 2016 at Hangzhou, the Yangtze River Delta (YRD) region of China. To improve air quality, control measures such as the closure of industrial plants with high emission, cessation of construction activities, and the restriction of traffic flow, were adopted by the government in the YRD region from the middle of August until the summit ended. According to the distance from the main stadium, the YRD region was divided into core control zone, strict control zone, and normal control zone. The adjacent provinces (such as Shanghai, Jiangsu, Anhui) also implemented some mitigation measures to ensure the air quality. Ningbo, as a city adjoined Hangzhou, was part of the strict control zone. During the G20 summit, the government reduced the emission of pollutants by controlling or prohibiting industrial, construction, and traffic activity in the YRD region. After the G20 summit, it was determined that typhoon Malarks had a significant influence on the YRD region, especially the coastal cities in the YRD region. Therefore, the strict control measures and typhoon occurred within a short period (September 2016) and offers a valuable opportunity to study the difference in the formation mechanism of PM2.5. Several studies have reported the air quality in Hangzhou under the emission control of the 2016 G20 summit. Li et al., (2017c) had found the high reduction of particulate matter in Hangzhou during the control period of G20 summit compared to the period previous to the G20 summit. Li et al., (2017d) found the night time transport of pollutants was unfavourable for the mitigation of pollutants in Hangzhou even under the strict emission control of the G20 summit. However, few studies were focused on the comparison of different formation mechanism of secondary inorganic aerosols influenced by the control measures and the typhoon weather. This study aims to: (1) differentiate between the characteristics of PM2.5 and the gaseous pollutants that are affected by the control measures and typhoon weather; (2) elucidate the influence of meteorological conditions on the water-soluble inorganic components of PM2.5; (3) investigate the formation mechanism of secondary inorganic aerosols under control measures and typhoon weather.
Section snippets
Description of the sampling site
The observations campaign was conducted on the rooftop of the Ningbo Urban Environment Observation and Research Station (NUEORS) building (29.87° N, 121.91° E, 10 m a.s.l), located in the Beilun District of Ningbo in the YRD region, China (Fig. 1). NUEORS is a suburban site that is 20 m away from the coastline and approximately 172 km northwest from the host city of the 2016 G20 summit. Southeast of the sampling site is a park, northeast is a residential area, while in the southwest and
General characteristics of PM2.5 and the gaseous pollutants
As shown in Fig. 2, the mean hourly concentration of PM2.5 at NUEORS during the observation period was 23.6 ± 12.0 μg m−3 with a range of 1.0–54.0 μg m−3. The temporal distribution of the gaseous pollutants is similar to that of PM2.5. Three cases were investigated during the observation period. Case 1 (0:00 1 September – 12:00 4 September) was influenced by the strict control measures implemented during the G20 summit. The emission reductions for industry, power plant, residential, and
Formation mechanism of PM2.5
The three cases occurred under different meteorological conditions and exhibited different chemical characteristics. This study attempted to explore the formation mechanism of PM2.5, particularly, with regard to the secondary inorganic components, with respect to the distinct meteorological conditions of the three cases.
Conclusions
In this study, we characterized the water-soluble inorganic chemical components and BC of PM2.5 and discussed the formation of SIA with the influence of the strict control measures and a typhoon in Ningbo during September 2016. The mean concentrations of PM2.5 were 37.48, 29.84, and 14.24 μg m−3 in the control case, normal case, and typhoon case, respectively. The effect of mitigation measures on PM2.5 concentration was far offset by the influence of stable weather and regional transport in the
CRediT authorship contribution statement
Yanru Zhang: Conceptualization, Methodology, Software, Investigation, Writing - review & editing. Zhenyu Hong: Methodology, Software, Writing - original draft. Jinsheng Chen: Conceptualization, Supervision, Writing - review & editing. Lingling Xu: Conceptualization, Writing - review & editing. Youwei Hong: Writing - original draft. Mengren Li: Writing - original draft. Hongfei Hao: Investigation, Writing - original draft. Yanting Chen: Investigation. Yuqing Qiu: Investigation. Xin Wu:
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This study was funded by the National Key Research and Development Program (2016YFC02005 & 2016YFE0112200), the National Natural Science Foundation of China (41575146), the Chinese Academy of Sciences Interdisciplinary Innovation Team Project, and the Natural Science Foundation of Fujian Province, China (2016J01201).
References (49)
- et al.
Effect of typhoon on atmospheric particulates in autumn in central Taiwan
Atmos. Environ.
(2009) - et al.
Mechanism of formation of the heaviest pollution episode ever recorded in the Yangtze River Delta, China
Atmos. Environ.
(2008) - et al.
Aerosol characteristics and sources in Yangzhou, China resolved by offline aerosol mass spectrometry and other techniques
Environ. Pollut.
(2017) - et al.
Heavy haze episodes in Beijing during January 2013: inorganic ion chemistry and source analysis using highly time-resolved measurements from an urban site
Sci. Total Environ.
(2016) - et al.
Effect of the pollution control measures on PM2.5 during the 2015 China Victory Day Parade: implication from water-soluble ions and sulfur isotope
Environ. Pollut.
(2016) - et al.
Chemical composition and size distribution of airborne particulate matters in Beijing during the 2008 Olympics
Atmos. Environ.
(2012) - et al.
Typical winter haze pollution in Zibo, an industrial city in China: characteristics, secondary formation, and regional contribution
Environ. Pollut.
(2017) - et al.
Chemical composition and source apportionment of the ambient PM2.5 in Hangzhou, China
Particuology
(2015) - et al.
PM2.5 in the Yangtze River Delta, China: chemical compositions, seasonal variations, and regional pollution events
Environ. Pollut.
(2017) - et al.
The effect of mitigation measures on size distributed mass concentrations of atmospheric particles and black carbon concentrations during the Olympic Summer Games 2008 in Beijing
Sci. Total Environ.
(2011)
Efficiency of mitigation measures to reduce particulate air pollution—a case study during the Olympic Summer Games 2008 in Beijing, China
Sci. Total Environ.
Spatio-temporal variations of black carbon concentrations in the Megacity Beijing
Environ. Pollut.
In situ measurements of SO2, NOx, NOy, and O3 in Beijing, China during August 2008
Sci. Total Environ.
Field observation on secondary organic aerosols during Asian dust storm periods: formation mechanism of oxalic acid and related compounds on dust surface
Atmos. Environ.
Water-soluble part of the aerosol in the dust storm season—evidence of the mixing between mineral and pollution aerosols
Atmos. Environ.
The ion chemistry and the source of PM 2.5 aerosol in Beijing
Atmos. Environ.
The ion chemistry, seasonal cycle, and sources of PM 2.5 and TSP aerosol in Shanghai
Atmos. Environ.
Effect of typhoon on atmospheric aerosol particle pollutants accumulation over Xiamen, China
Chemosphere
Source regions and transport pathways of PM2.5 at a regional background site in East China
Atmos. Environ.
Environmental Technology Verification Report: ETV Advanced Monitoring Systems Center Applikon MARGA Semi-continuous Ambient Air Monitoring System
Description OF the HYSPLIT_4 modeling system
Nat. Ocean. Atmos. Adm. Tech. Memorand. Erl Arl
Direct observation of heterogeneous chemistry in the atmosphere
Science
Heterogeneous photochemistry in the atmosphere
Chem. Rev.
Surface electric fields of aqueous solutions of NH4NO3, Mg(NO3)2, NaNO3, and LiNO3: implications for atmospheric aerosol chemistry
J. Phys. Chem. C
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