Agenda-setting of air quality policy in Hong Kong : a study on vehicle emissions

2011 ◽  
Author(s):  
Sin-ki, Emily Chan
Keyword(s):  
Hong Kong ◽  
Air Quality ◽  
Agenda Setting ◽  
Vehicle Emissions ◽  
Quality Policy

scholarly journals Quantifying Air Pollutant Variations during COVID-19 Lockdown in a Capital City in Northwest China

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 788
Author(s):  
Rong Feng ◽  
Hongmei Xu ◽  
Zexuan Wang ◽  
Yunxuan Gu ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Rural Areas ◽  
Vehicle Emissions ◽  
Motor Vehicle ◽  
Northwest China ◽  
Air Pollutant ◽  
Capital City ◽  
Air Pollution Control ◽  
Motor Vehicle Emissions

In the context of the outbreak of coronavirus disease 2019 (COVID-19), strict lockdown policies were implemented to control nonessential human activities in Xi’an, northwest China, which greatly limited the spread of the pandemic and affected air quality. Compared with pre-lockdown, the air quality index and concentrations of PM2.5, PM10, SO2, and CO during the lockdown reduced, but the reductions were not very significant. NO2 levels exhibited the largest decrease (52%) during lockdown, owing to the remarkable decreased motor vehicle emissions. The highest K+ and lowest Ca2+ concentrations in PM2.5 samples could be attributed to the increase in household biomass fuel consumption in suburbs and rural areas around Xi’an and the decrease in human physical activities in Xi’an (e.g., human travel, vehicle emissions, construction activities), respectively, during the lockdown period. Secondary chemical reactions in the atmosphere increased in the lockdown period, as evidenced by the increased O3 level (increased by 160%) and OC/EC ratios in PM2.5 (increased by 26%), compared with pre-lockdown levels. The results, based on a natural experiment in this study, can be used as a reference for studying the formation and source of air pollution in Xi’an and provide evidence for establishing future long-term air pollution control policies.

scholarly journals Cleaning up the air: Effectiveness of air quality policy for SO<sub>2</sub> and NO<sub><i>x</i></sub> emissions in China

2016 ◽  
Author(s):  
Ronald J. van der A ◽  
Bas Mijling ◽  
Jieying Ding ◽  
Maria Elissavet Koukouli ◽  
Fei Liu ◽  
...  
Keyword(s):  
Air Quality ◽  
Fuel Consumption ◽  
Fossil Fuel ◽  
Transport Sector ◽  
Nox Emissions ◽  
So2 Emissions ◽  
Provincial Level ◽  
Fossil Fuel Consumption ◽  
Public Data ◽  
Quality Policy

Abstract. Air quality observations by satellite instruments are spatially consistent, and have a regular temporal resolution, which make them very useful in studying long-term trends in atmospheric species. To monitor air quality trends in China for the period 2005–2015 we derive SO2 columns and NOx emissions on a provincial level with an unprecedented accuracy. To put these trends into perspective they are compared with public data on energy consumption and the environmental policies of China. We distinguish the effect of air quality regulations from economic growth by comparing them relatively to fossil fuel consumption. Pollutant levels, per unit of fossil fuel, are used to assess the effectiveness of air quality regulations. We note that the desulphurisation regulations enforced in 2005–2006 only had a significant effect in the years 2008–2009 when a much stricter control of the actual use of the installations began. For national NOx emissions a distinct decreasing trend is only visible since 2012, but the emission peak year differs from province to province. Unlike SO2, emissions of NOx are highly related to traffic. Furthermore, regulations for NOx emissions are partly decided on a provincial level. The last three years show both a reduction in SO2 and NOx emissions per fossil fuel unit, since the authorities have implemented several new environmental regulations. Despite an increasing fossil fuel consumption and a growing transport sector, the effects of air quality policy in China are clearly visible. Without the air quality regulations the concentration of SO2 would be almost 3 times higher and the NO2 concentrations would be at least 30 % higher than they are today in China.

scholarly journals Evaluating Vehicle Emission Control Policies using on-Road Mobile Measurements and Continuous Wavelet Transform: a Case Study during the Asia-Pacific Economic Cooperation Forum, China 2014

2016 ◽  
Author(s):  
Ziqiang Tan ◽  
Yanwen Wang ◽  
Chunxiang Ye ◽  
Yi Zhu ◽  
Yingruo Li ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Air Quality ◽  
Continuous Wavelet Transform ◽  
Vehicle Emissions ◽  
Emission Control ◽  
Control Policy ◽  
Asia Pacific ◽  
Vehicle Emission ◽  
Continuous Wavelet ◽  
Asia Pacific Economic Cooperation

Abstract. Vehicle emissions are major sources of atmospheric pollutants in urban areas, especially in megacities around the world. Various vehicle emission control policies have been implemented to improve air quality. However, the effectiveness of these policies is unclear, due to a lack of systematic evaluation and sound methodologies. During the Asia-Pacific Economic Cooperation (APEC) Forum, China 2014, the Chinese government implemented the strictest vehicle emission control policy in the country's history, which provided an opportunity to evaluate its effectiveness, based on our recently developed method. To evaluate the vehicle emission reduction, we used a mobile research platform to measure the main air pollutants (PM2.5, black carbon (BC), SO2, CO, NOx and O3) on the 4th ring road of the city of Beijing, combined with a continuous wavelet transform method (CWT) to separate out "instantaneous emissions" by passing vehicles. The results suggested that our measurements captured the spatial distribution and variation of atmospheric pollutant concentrations on the 4th ring road. The "instantaneous concentration" decomposed by the CWT method represents on-road emissions better than other methods reported in the literature. With this method, we found that the daytime vehicle emission of CO and NOx decreased by 28.1 and 16.3 %, respectively, during the APEC period relative to the period before APEC, and by 39.3 and 38.5 %, respectively, relative to the period after APEC. The nighttime vehicle emissions of CO and NOx decreased by 56.0 and 60.7 %, respectively, during the APEC period relative to the period after APEC. Because vehicle emissions of NOx and CO contribute considerably to the total emissions of these pollutants in Beijing, the vehicle emission control policy implementation was extremely successful in controlling air quality during APEC 2014, China.

scholarly journals Understanding sources of organic aerosol during CalNex-2010 using the CMAQ-VBS

2015 ◽  
Vol 15 (19) ◽  
pp. 26745-26793 ◽  
Author(s):  
M. C. Woody ◽  
K. R. Baker ◽  
P. L. Hayes ◽  
J. L. Jimenez ◽  
B. Koo ◽  
...  
Keyword(s):  
Air Quality ◽  
Vehicle Emissions ◽  
Organic Aerosol ◽  
Point Sources ◽  
Photochemical Oxidation ◽  
Basis Set ◽  
High Dispersion ◽  
Monitoring Networks ◽  
Diurnal Profile ◽  
Formation Efficiency

Abstract. Community Multiscale Air Quality (CMAQ) model simulations utilizing the volatility basis set (VBS) treatment for organic aerosols (CMAQ-VBS) were evaluated against measurements collected at routine monitoring networks (Chemical Speciation Network (CSN) and Interagency Monitoring of Protected Visual Environments (IMPROVE)) and those collected during the 2010 California at the Nexus of Air Quality and Climate Change (CalNex) field campaign to examine important sources of organic aerosol (OA) in southern California. CMAQ-VBS (OA lumped by volatility, semivolatile POA) underpredicted total organic carbon (OC) at CSN (−25.5 % Normalized Median Bias (NMdnB)) and IMPROVE (−63.9 % NMdnB) locations and total OC was underpredicted to a greater degree compared to the CMAQ-AE6 (9.9 and −55.7 % NMdnB, respectively; semi-explicit OA treatment, SOA lumped by parent hydrocarbon, nonvolatile POA). However, comparisons to aerosol mass spectrometer (AMS) measurements collected at Pasadena, CA indicated that CMAQ-VBS better represented the diurnal profile and the primary/secondary split of OA. CMAQ-VBS secondary organic aerosol (SOA) underpredicted the average measured AMS oxygenated organic aerosol (OOA, a surrogate of SOA) concentration by a factor of 5.2 (4.7 μg m−3 measured vs. 0.9 μg m−3 modeled), a considerable improvement to CMAQ-AE6 SOA predictions, which were approximately 24× lower than the average AMS OOA concentration. We use two new methods, based on species ratios and on a simplified SOA parameterization from the observations, to apportion the SOA underprediction for CMAQ-VBS to too slow photochemical oxidation (estimated as 1.5× lower than observed at Pasadena using − log (NOx: NOy)), low intrinsic SOA formation efficiency (low by 1.6 to 2× for Pasadena), and too low emissions or too high dispersion for the Pasadena site (estimated to be 1.6 to 2.3× too low/high). The first and third factors will be similar for CMAQ-AE6, while the intrinsic SOA formation efficiency for that model is estimated to be too low by about 7×. For CMAQ-VBS, 90 % of the anthropogenic SOA mass formed was attributed to aged secondary semivolatile vapors (70 % originating from volatile organic compounds (VOCs) and 20 % from intermediate volatility compounds (IVOCs)). From source-apportioned model results, we found most of the CMAQ-VBS modeled POA at the Pasadena CalNex site was attributable to meat cooking emissions (48 %, and consistent with a substantial fraction of cooking OA in the observations), compared to 18 % from gasoline vehicle emissions, 13 % from biomass burning (in the form of residential wood combustion), and 8 % from diesel vehicle emissions. All "other" inventoried emission sources (e.g. industrial/point sources) comprised the final 13 %. The CMAQ-VBS semivolatile POA treatment underpredicted AMS hydrocarbon-like OA (HOA) + cooking-influenced OA (CIOA) at Pasadena by a factor of 1.8 (1.16 μg m−3 modeled vs. 2.05 μg m−3 observed) compared to a factor of 1.4 overprediction of POA in CMAQ-AE6, but did well to capture the AMS diurnal profile of HOA and CIOA, with the exception of the midday peak. We estimated that using the National Emission Inventory (NEI) POA emissions without scaling to represent SVOCs underestimates SVOCs by ~1.7×.

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