Variation of ambient non-methane hydrocarbons in Beijing city in summer 2008

Wang, B.; Shao, Min; Lü, Sihua; Yuan, Bin; Zhao, Yuanhong; Wang, M.; Zhang, S. Q.; Wu, Di

doi:10.5194/acp-10-5911-2010

Cited by 130 publications

(79 citation statements)

References 18 publications

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“…The estimates of NO x reduction are consistent with previous reports based on satellite observations, which indicated a reduction of ∼40-60 % in the column density of NO 2 over Beijing during the Olympic Games (Mijling et al, 2009;Witte et al, 2009). Besides, the reductions in the vehicular emissions of the other air pollutants have also been validated by a series of groundbased observations Wang et al, 2009aWang et al, , b, 2010a. Evidently, the air pollution control measures had successfully reduced the ambient levels of the primary air pollutants in Beijing during the Olympic Games.…”

Section: Introductionmentioning

confidence: 84%

Photochemical production of ozone in Beijing during the 2008 Olympic Games

et al. 2011

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Abstract. As a part of the CAREBeijing-2008 campaign, observations of O 3 , oxides of nitrogen (NO x and NO y ), CO, and hydrocarbons (NMHCs) were carried out at the air quality observatory of the Peking University in Beijing, China during August 2008, including the period of the 29th Summer Olympic Games. The measurements were compared with those of the CAREBeijing-2006 campaign to evaluate the effectiveness of the air pollution control measures, which were conducted for improving the air quality in Beijing during the Olympics. The results indicate that significant reduction in the emissions of primary air pollutants had been achieved; the monthly averaged mixing ratios of NO x , NO y , CO, and NMHCs decreased by 42.2, 56.5, 27.8, and 49.7 %, respectively. In contrast to the primary pollutants, the averaged mixing ratio of O 3 increased by 42.2 %. Nevertheless, it was revealed that the ambient levels of total oxidant (O x = O 3 +NO 2 +1.5NO z ) and NO z were reduced by 21.3 and 77.4 %, respectively. The contradictions between O 3 and O x were further examined in two case studies. Ozone production rates of 30-70 ppbv h −1 and OPEx of ∼8 mole mole −1 were observed on a clear-sky day in spite of the reduced levels of precursors. In that case, it was found that the mixing ratio of O 3 increased with the increasing NO 2 /NO ratio, whereas the NO z mixing ratio leveled off when NO 2 /NO>8. Consequently, the ratio of O 3 to NO z increased to above 10, indicating the shift from VOC-sensitive regime to NO x -sensitive regime. However, in the other case, it was found that the O 3 production was inhibited significantly due to substantial reduction in the NMHCs. According to the observations, it was suggested that the O 3 and/or O x production rates in BeijingCorrespondence to: C. C.-K. Chou (ckchou@rcec.sinica.edu.tw) should have been reduced as a result of the reduction in the emissions of precursors during the Olympic period. However, the nighttime O 3 levels increased due to a decline in the NO-O 3 titration, and the midday O 3 peak levels were elevated because of the shift in the photochemical regime and the inhibition of NO z formation.

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Section: Introductionmentioning

confidence: 84%

Photochemical production of ozone in Beijing during the 2008 Olympic Games

et al. 2011

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“…To assess the possible impact of emission mitigation measures in Beijing during the period analysed in this study, the WRF-Chem model was run for 2 weeks (1-15 August 2008) with reduced pollutant emissions from the transport, industrial and solvent use sectors, following the mitigation strategy during the Olympics described in Wang et al (2010). For example, emissions of all species in the transport sector were reduced by 75 % in Beijing and 20 % in the area 200 km from Beijing, corresponding to eight model grid cells around Beijing in this model.…”

Section: Discussionmentioning

confidence: 99%

“…Continental-scale horizontal and vertical transport of ozone and aerosols, important for radiative impacts, are assessed downwind of the main emission regions using aerosol lidar data as well as satellite aerosol lidar and tropospheric ozone, CO and NO 2 column data. Emissions (polluting vehicles, chemical, power plants) in the Beijing municipality were mitigated from 30 June 2008 and 20 September 2008 (see the detailed mitigation plan in Wang et al, 2010) in the context of the Beijing Olympic and Paralympic games. We examine the effects of these emission reductions on atmospheric composition using a regional model in order to assess potential influences on the model results compared to data collected in the Beijing region.…”

Section: Introductionmentioning

confidence: 99%

Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

et al. 2016

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Abstract. The ability of seven state-of-the-art chemistryaerosol models to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over eastern Asia in summer 2008, is evaluated. The study focuses on the performance of models used to assess impacts of pollutants on climate and air quality as part of the EU ECLIPSE project. Models, run using the same ECLIPSE emissions, are compared over different spatial scales to in situ surface, vertical profiles and satellite data. Several rather clear biases are found between model results and observations, including overestimation of ozone at rural locations downwind of the main emission regions in China, as well as downwind over the Pacific. Several models produce too much ozone over polluted regions, which is then transported downwind. Analysis points to different factors related to the ability of models to simulate VOC-limited regimes over polluted regions and NO x limited regimes downwind. This may also be linked to biases compared to satellite NO 2 , indicating overestimation of NO 2 over and to the north of the northern China Plain emission region. On the other hand, model NO 2 is too low to the south and west of this region and over South Korea/Japan. Overestimation of ozone is linked to systematic underestimation of CO particularly at rural sites and downwind of the main Chinese emission regions. This is likely to be due to enhanced destruction of CO by OH. Overestimation of Asian ozone and its transport downwind impliesPublished by Copernicus Publications on behalf of the European Geosciences Union. With regard to aerosols, most models reproduce the satellite-derived AOD patterns over eastern China. Our study nevertheless reveals an overestimation of ECLIPSE model mean surface BC and sulphate aerosols in urban China in summer 2008. The effect of the short-term emission mitigation in Beijing is too weak to explain the differences between the models. Our results rather point to an overestimation of SO 2 emissions, in particular, close to the surface in Chinese urban areas. However, we also identify a clear underestimation of aerosol concentrations over northern India, suggesting that the rapid recent growth of emissions in India, as well as their spatial extension, is underestimated in emission inventories. Model deficiencies in the representation of pollution accumulation due to the Indian monsoon may also be playing a role. Comparison with vertical aerosol lidar measurements highlights a general underestimation of scattering aerosols in the boundary layer associated with overestimation in the free troposphere pointing to modelled aerosol lifetimes that are too long. This is likely linked to too strong vertical transport and/or insufficient deposition efficiency during transport or export from the boundary layer, rather than chemical processing (in the case of sulphate aerosols). Underestimation of sulphate in the boundary layer implies potentially large errors in simulated aerosol-cloud interactions, via impacts on boundary-layer clouds...

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“…On-road measurements reported significant (12-70%) decreases in the ambient concentrations of CO, NO x , SO 2 , black carbon (BC), benzene, toluene, ethylbenzene, and xylenes (BTEX), and PM 1 during the Olympics (Wang et al, 2009a). Atmospheric measurements at other urban sites showed a decrease in the concentration of 35-43% for fine and coarse particulate matter (Wang et al, 2009b), 74% for BC (Wang et al, 2009c), 47-64% for BTEX , and 35% for total non-methane hydrocarbons (Wang et al, 2010a). These results were based on a comparison of the data obtained during the Olympics with those from non-Olympic periods (before and/or after the Olympics and Para-Olympics).…”

Section: Introductionmentioning

confidence: 99%

Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact

et al. 2010

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Abstract. This paper presents the first results of the measurements of trace gases and aerosols at three surface sites in and outside Beijing before and during the 2008 Olympics. The official air pollution index near the Olympic Stadium and the data from our nearby site revealed an obvious association between air quality and meteorology and different responses of secondary and primary pollutants to the control measures. Ambient concentrations of vehicle-related nitrogen oxides (NO x ) and volatile organic compounds (VOCs) at an urban site dropped by 25% and 20-45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM 2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants) improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions). A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed >34-88% to the peak ozone concentrations at the urban site in Beijing. Regional sources also contributed significantly to the CO concentrations in urban Beijing. Ozone production efficiencies at two sites were low (∼3 ppbv/ppbv), indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO 2 ), total sulfur (SO 2 +PM 2.5 sulCorrespondence to: T. Wang (cetwang@polyu.edu.hk) fate), carbon monoxide (CO), reactive aromatics (toluene and xylenes) sharply decreased (by 8-64%) in 2008, but no significant changes were observed for the concentrations of PM 2.5 , fine sulfate, total odd reactive nitrogen (NO y ), and longer lived alkanes and benzene. We suggest that these results indicate the success of the government's efforts in reducing emissions of SO 2 , CO, and VOCs in Beijing, but increased regional emissions during [2005][2006][2007][2008]. More stringent control of regional emissions will be needed for significant reductions of ozone and fine particulate pollution in Beijing.

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Variation of ambient non-methane hydrocarbons in Beijing city in summer 2008

Cited by 130 publications

References 18 publications

Photochemical production of ozone in Beijing during the 2008 Olympic Games

Photochemical production of ozone in Beijing during the 2008 Olympic Games

Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact

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