scholarly journals Observation-Based Summer O3 Control Effect Evaluation: A Case Study in Chengdu, a Megacity in Sichuan Basin, China

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1278
Author(s):  
Qinwen Tan ◽  
Li Zhou ◽  
Hefan Liu ◽  
Miao Feng ◽  
Yang Qiu ◽  
...  
Keyword(s):  
Control Period ◽  
Photochemical Reactions ◽  
Control Measures ◽  
Effective Control ◽  
Industrial Emissions ◽  
Transport Channel ◽  
Photochemical Pollution ◽  
Control Policies ◽  
Secondary Formation ◽  
Vehicular Exhaust

Ground-level ozone (O3), which is mainly from the photochemical reactions of NOx and volatile organic compounds (VOCs), has become a crucial pollutant obstructing air quality improvement in China. Understanding the composition, temporal variability and source apportionment of VOCs is necessary for determining effective control measures to minimize VOCs and their related photochemical pollution. To provide a comprehensive analysis of VOC sources and their contributions to ozone formation in the city of Chengdu—a megacity with the highest rates of industrial and economic development in southwest China—we conducted a one-month monitoring project at three urban sites (Shuangliu, Xindu, Junpingjie; SL, XD and JPJ, respectively) along the main north–south meteorological transport channel before and during the implemented control measures. Alkanes were the dominant group at each site, contributing to around 50% of the observed total VOCs, followed by oxygen-containing VOCs (OVOCs), aromatics, halohydrocarbons and alkenes. During the control period, the mixing ratios of most measured VOC species decreased, and O3 concentrations were down by at least 20%. VOC species experiencing the most effect from control were aromatics and OVOCs, which had higher O3 formation reactivity. This indicated that the control policies had significant influence on reductions of reactive VOC species. We also identified VOC sources at SL and XD using positive matrix factorization (PMF) and assessed their contributions to photochemical O3 formation by calculating the O3 formation potential (OFP) based on mass concentrations and maximum incremental reactivity of related VOCs. Five dominant VOC sources were identified, with the highest contributions from vehicular exhaust and fuel evaporation before control, followed by solvent utilization, biogenic background and secondary formation, and industrial emissions. Contribution from vehicular exhaust was reduced the most at SL, while at XD, secondary formation VOCs decreased significantly. VOCs from vehicular and industrial emissions and solvent utilization were found to be the dominant precursors for OFPs, particularly the species of xylenes, toluene and propene. Our results therefore suggest that priority should be given to the alleviation of photochemical pollutants for effective control of O3 formation in Chengdu. The findings from this work have important implications for formulating effective emission control policies in Chengdu.

scholarly journals Sources of volatile organic compounds and policy implications for regional ozone pollution control in an urban location of Nanjing, East China

2020 ◽  
Vol 20 (6) ◽  
pp. 3905-3919 ◽  
Author(s):  
Qiuyue Zhao ◽  
Jun Bi ◽  
Qian Liu ◽  
Zhenghao Ling ◽  
Guofeng Shen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Control Measures ◽  
Policy Implications ◽  
Effective Control ◽  
Urban Site ◽  
Industrial Emissions ◽  
Photochemical Pollution ◽  
Volatile Organic ◽  
Vehicular Exhaust

Abstract. Understanding the composition, temporal variability and source apportionment of volatile organic compounds (VOCs) is necessary for determining effective control measures to minimize VOCs and their related photochemical pollution. To provide a comprehensive analysis of VOC sources and their contributions to ozone (O3) formation in the Yangtze River Delta (YRD) – a region experiencing the highest rates of industrial and economic development in China – we conducted a 1-year sampling exercise using a thermal desorption GC (gas chromatography) system for the first time at an urban site in Nanjing (JAES site). Alkanes were the dominant group at the JAES site, contributing ∼53 % to the observed total VOCs, followed by aromatics (∼17 %), acetylene (∼17 %) and alkenes (∼13 %). We identified seasonal variability in total VOCs (TVOCs) with maximum and minimum concentrations in winter and summer, respectively. Morning and evening peaks and a daytime trough were identified in the diurnal VOC patterns. We identified VOC sources using positive matrix factorization (PMF) and assessed their contributions to photochemical O3 formation by calculating the O3 formation potential (OFP) based on the mass concentrations and maximum incremental reactivities of VOCs. The PMF model identified five dominant VOC sources, with highest contributions from diesel vehicular exhaust (34±5 %), followed by gasoline vehicular exhaust (27±3 %), industrial emissions (19±2 %), fuel evaporation (15±2 %) and biogenic emissions (4±1 %). The results of the OFP calculation inferred that VOCs from industrial and vehicular emissions were found to be the dominant precursors for OFP, particularly the VOC species of xylenes, toluene and propene, and top priority should be given to these for the alleviation of photochemical smog. Our results therefore highlight that priority should be given to limited VOC sources and species for effective control of O3 formation in Nanjing.

scholarly journals Enhanced hydrophobicity and volatility of submicron aerosols under severe emission control conditions in Beijing

2017 ◽  
Author(s):  
Yuying Wang ◽  
Fang Zhang ◽  
Zhanqing Li ◽  
Haobo Tan ◽  
Hanbing Xu ◽  
...  
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Control Period ◽  
Emission Control ◽  
Control Measures ◽  
Particle Sizes ◽  
Industrial Emissions ◽  
Aerosol Hygroscopicity ◽  
Emission Control Measures

Abstract. A series of strict emission control measures were implemented in Beijing and the surrounding seven provinces to ensure good air quality during the 2015 China Victory Day parade, rendering a unique opportunity to investigate anthropogenic impact of aerosol properties. Submicron aerosol hygroscopicity and volatility were measured during and after the control period using a hygroscopic and volatile tandem differential mobility analyzer (H/V-TDMA) system. Three periods, namely, the control clean period (Clean1), the non-control clean period (Clean2), and the non-control pollution period (Pollution), were selected to study the effect of the emission control measures on aerosol hygroscopicity and volatility. Aerosol particles became more hydrophobic and volatile due to the emission control measures. The hygroscopicity parameter (κ) of 40–200 nm particles decreased by 32.0 %–8.5 % during the Clean1 period relative to the Clean2 period, while the volatile shrink factor (SF) of 40–300 nm particles decreased by 7.5 %–10.5 %. The emission controls also changed the diurnal variation patterns of both the probability density function of κ (κ-PDF) and the probability density function of SF (SF-PDF). During Clean1 the κ-PDF showed one nearly-hydrophobic (NH) mode for particles in the nucleation mode, which was likely due to the dramatic reduction in industrial emissions of inorganic trace gases. Compared to the Pollution period, particles observed during the Clean1 and Clean2 periods exhibited a more significant non-volatile (NV) mode throughout the day, suggesting a more externally-mixed state particularly for the 150 nm particles. Aerosol hygroscopicities increased as particle sizes increased, with the greatest increases seen during the Pollution period. Accordingly, the aerosol volatility became weaker (i.e., SF increased) as particle sizes increased during the Clean1 and Clean2 periods, but no apparent trend was observed during the Pollution period. Based on a correlation analysis of the number fractions of NH and NV particles, we found that a higher number fraction of hydrophobic and volatile particles during the emission control period.

scholarly journals Sources of volatile organic compounds and policy implications for regional ozone pollution control in an urban location of Nanjing, East China

2019 ◽  
Author(s):  
Qiuyue Zhao ◽  
Jun Bi ◽  
Zhenghao Ling ◽  
Qian Liu ◽  
Guofeng Shen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Policy Implications ◽  
Chemical Mechanism ◽  
Effective Control ◽  
Urban Site ◽  
Biogenic Emissions ◽  
Industrial Emissions ◽  
Photochemical Pollution ◽  
Volatile Organic

Abstract. Understanding the composition, temporal variability, and source apportionment of volatile organic compounds (VOCs) is necessary for determining effective control measures to minimize VOCs and its related photochemical pollution. To provide a comprehensive analysis of VOC sources and their contributions to ozone (O3) formation in the Yangtze River Delta (YRD) – a region experiencing highest rates of industrial and economic development in China, we conducted a one-year sampling exercise for the first time at an urban site in Nanjing (JAES site). Alkanes were the dominant group at the JAES site, contributing ~ 53 % to the observed total VOCs, followed by aromatics (~ 17 %), acetylene (~ 17 %), and alkenes (~ 13 %). We identified seasonal variability in TVOCs with maximum and minimum concentrations in winter and summer, respectively. A morning and evening peak and a daytime trough were identified in the diurnal VOCs patterns. We identified the source apportionments of VOCs and their contributions to photochemical O3 formation using the Positive Matrix Factorization (PMF) and observation-based model together with a Master Chemical Mechanism (MCM). The PMF model identified five dominant VOC sources, with highest contributions from diesel vehicular exhausts (34 ± 5 %), followed by gasoline vehicular exhausts (27 ± 3 %), industrial emissions (19 ± 2 %), fuel evaporation (15 ± 2 %) and biogenic emissions (4 ± 1 %). The results from the OBM-MCM model simulation inferred photochemical O3 formation to be VOC-limited at the JAES site when considering both the reactivity and abundance of the individual VOC species in each source category. Further, VOCs from vehicular and industrial emissions were found to be the dominant control on O3 formation, particularly the VOC species m,p-xylene, toluene and propene, which top priorities should be given to the alleviation of photochemical smog. However, when considering the reactivity and abundance of VOC species, the contribution of biogenic emissions to O3 pollution was significantly reduced. Our results therefore highlight the need to consider both the abundance and reactivity of individual VOC species in order to develop effective control strategies to minimize photochemical pollution in Nanjing.

scholarly journals Enhanced hydrophobicity and volatility of submicron aerosols under severe emission control conditions in Beijing

2017 ◽  
Vol 17 (8) ◽  
pp. 5239-5251 ◽  
Author(s):  
Yuying Wang ◽  
Fang Zhang ◽  
Zhanqing Li ◽  
Haobo Tan ◽  
Hanbing Xu ◽  
...  
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Control Period ◽  
Emission Control ◽  
Control Measures ◽  
Particle Sizes ◽  
Industrial Emissions ◽  
Aerosol Hygroscopicity ◽  
Emission Control Measures

Abstract. A series of strict emission control measures was implemented in Beijing and the surrounding seven provinces to ensure good air quality during the 2015 China Victory Day parade, rendering a unique opportunity to investigate the anthropogenic impact of aerosol properties. Submicron aerosol hygroscopicity and volatility were measured during and after the control period using a hygroscopic and volatile tandem differential mobility analyzer (H/V-TDMA) system. Three periods, namely the control clean period (Clean1), the non-control clean period (Clean2), and the non-control pollution period (Pollution), were selected to study the effect of the emission control measures on aerosol hygroscopicity and volatility. Aerosol particles became more hydrophobic and volatile due to the emission control measures. The hygroscopicity parameter (κ) of 40–200 nm particles decreased by 32.0–8.5 % during the Clean1 period relative to the Clean2 period, while the volatile shrink factor (SF) of 40–300 nm particles decreased by 7.5–10.5 %. The emission controls also changed the diurnal variation patterns of both the probability density function of κ (κ-PDF) and the probability density function of SF (SF-PDF). During Clean1 the κ-PDF showed one nearly hydrophobic (NH) mode for particles in the nucleation mode, which was likely due to the dramatic reduction in industrial emissions of inorganic trace gases. Compared to the Pollution period, particles observed during the Clean1 and Clean2 periods exhibited a more significant nonvolatile (NV) mode throughout the day, suggesting a more externally mixed state particularly for the 150 nm particles. Aerosol hygroscopicities increased as particle sizes increased, with the greatest increases seen during the Pollution period. Accordingly, the aerosol volatility became weaker (i.e., SF increased) as particle sizes increased during the Clean1 and Clean2 periods, but no apparent trend was observed during the Pollution period. Based on a correlation analysis of the number fractions of NH and NV particles, we found that a higher number fraction of hydrophobic and volatile particles during the emission control period.

scholarly journals Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

2010 ◽  
Vol 10 (8) ◽  
pp. 19737-19761 ◽  
Author(s):  
J. C. Gong ◽  
T. Zhu ◽  
M. Hu ◽  
L. W. Zhang ◽  
H. Cheng ◽  
...  
Keyword(s):  
Air Pollution ◽  
Pollution Control ◽  
Control Period ◽  
Photochemical Reactions ◽  
Control Measures ◽  
Health Concern ◽  
Air Pollution Control ◽  
Beijing Olympics ◽  
Ambient Concentrations ◽  
Early Fall

Abstract. Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein) in a central Beijing site in the summer and early fall of 2008 (from June to October). Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's air quality during the Olympics had any impact on concentrations of the three aldehydes. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.34 ± 15.12 μg/m3, 27.09 ± 15.74 μg/m3 and 2.32 ± 0.95 μg/m3, respectively, for the entire period of measurements, all being the highest among the levels measured in cities around the world in photochemical smog seasons. Among the three measured aldehydes, only acetaldehyde had a substantially reduced mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Formaldehyde and acrolein followed the changing pattern of temperature and were each significantly correlated with ozone (a secondary product of photochemical reactions). In contrast, acetaldehyde was significantly correlated with several pollutants emitted mainly from local emission sources (e.g., NO2, CO, and PM2.5). These findings suggest that local direct emissions had a larger impact on acetaldehyde than formaldehyde and acrolein.

scholarly journals Spatial–temporal variations and process analysis of O<sub>3</sub> pollution in Hangzhou during the G20 summit

2020 ◽  
Vol 20 (10) ◽  
pp. 5963-5976 ◽  
Author(s):  
Zhi-Zhen Ni ◽  
Kun Luo ◽  
Yang Gao ◽  
Xiang Gao ◽  
Fei Jiang ◽  
...  
Keyword(s):  
Process Analysis ◽  
Surface Ozone ◽  
Control Period ◽  
Emission Control ◽  
Photochemical Reactions ◽  
Influential Factors ◽  
Control Measures ◽  
Phase Iii ◽  
Ozone Formation ◽  
Vertical Diffusion

Abstract. Serious urban ozone (O3) pollution was observed during the campaign of 2016 G20 summit in Hangzhou, China, while other pollutants had been significantly reduced by the short-term emission control measures. To understand the underlying mechanism, the Weather Research Forecast with Chemistry (WRF-Chem) model is used to investigate the spatial and temporal O3 variations in Hangzhou from 24 August to 6 September 2016. The model is first successfully evaluated and validated for local and regional meteorological and chemical parameters by using the ground and upper-air level observed data. High ozone concentrations, temporally during most of the daytime emission control period and spatially from the surface to the top of the planetary boundary layer, are captured in Hangzhou and even the whole Yangtze River Delta region. Various atmospheric processes are further analyzed to determine the influential factors of local ozone formation through the integrated process rate method. Interesting horizontal and vertical advection circulations of O3 are observed during several short periods, and the effects of these processes are nearly canceled out. As a result, ozone pollution is mainly attributed to the local photochemical reactions that are not obviously influenced by the emission reduction measures. The ratio of reduction of Volatile Organic Compounds (VOCs) to that of NOx is a critical parameter that needs to be carefully considered for future alleviation of ozone formation. In addition, the vertical diffusion from the upper-air background O3 also plays an important role in shaping the surface ozone concentration. These results provide insight into urban O3 formation in Hangzhou and support the Model Intercomparison Study Asia Phase III (MICS-Asia Phase III).

The Portuguese alcohol industry: friend or foe of public health authorities?

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Paixão ◽  
M Mialon
Keyword(s):  
Public Health ◽  
Control Measures ◽  
Alcoholic Beverages ◽  
Effective Control ◽  
Trade Association ◽  
Control Policies ◽  
Trade Associations ◽  
Alcohol Industry ◽  
Health Authorities ◽  
Public Health Authorities

Abstract The influence of the alcohol industry is considered one of the most important obstacles to the implementation of policies that aim to tighten alcohol control. However, to our knowledge, our research is the first one to document the influence of the alcohol industry in the country, despite a 6.8% prevalence of alcohol use disorders and alcohol not featuring in the current National Health plan. We performed a qualitative thematic analysis of information available on websites and social media pages of trade associations, charities funded by the alcohol industry, government, universities and media material. This analysis was based on the “Policy Dystopia” framework, dividing the strategies we found as either instrumental (action-based) and discursive (argument-based). Overall, out of the 198 written records, 56% were instrumental and 44% discursive. The alcohol industry's representatives are part of the executive commission of the national task force responsible for consulting on policies regarding alcohol. We also found evidence of extensive community involvement through cooperation with security forces, among others. Also, after a discussion by the Portuguese Parliament of a possible increase in taxation of alcoholic beverages, a trade association delivered a study it had ordered from a consultancy company refuting any increase. Trade associations also claimed stricter control measures were not necessary in southern European countries, such as Portugal, and they were only appropriate for countries with more harmful drinking patterns. When referring to health risks causes by alcohol consumption, the association with breast cancer was only found once with misleading language describing it as “chest cancer”. This research has shown several tactics employed by the alcohol industry in Portugal and, as such, helped counteract some arguments used by the industry. This can enable the implementation of more effective control policies. Key messages Public health authorities should document the industry’s tactics in order to implement effective control policies regarding alcohol and other substances. There is a need for audits of health information made public by the alcohol industry.

Characterizing the effectiveness of COVID-19 mitigation measures: A data-centric approach (Preprint)

2020 ◽  
Author(s):  
Lukman Olagoke ◽  
Ahmet E. Topcu
Keyword(s):  
Control Measure ◽  
Control Measures ◽  
World Health ◽  
Mitigation Measures ◽  
Effective Control ◽  
The World ◽  
Decision Making Processes ◽  
And Performance ◽  
Health Organization ◽  
The Impact

BACKGROUND COVID-19 represents a serious threat to both national health and economic systems. To curb this pandemic, the World Health Organization (WHO) issued a series of COVID-19 public safety guidelines. Different countries around the world initiated different measures in line with the WHO guidelines to mitigate and investigate the spread of COVID-19 in their territories. OBJECTIVE The aim of this paper is to quantitatively evaluate the effectiveness of these control measures using a data-centric approach. METHODS We begin with a simple text analysis of coronavirus-related articles and show that reports on similar outbreaks in the past strongly proposed similar control measures. This reaffirms the fact that these control measures are in order. Subsequently, we propose a simple performance statistic that quantifies general performance and performance under the different measures that were initiated. A density based clustering of based on performance statistic was carried out to group countries based on performance. RESULTS The performance statistic helps evaluate quantitatively the impact of COVID-19 control measures. Countries tend show variability in performance under different control measures. The performance statistic has negative correlation with cases of death which is a useful characteristics for COVID-19 control measure performance analysis. A web-based time-line visualization that enables comparison of performances and cases across continents and subregions is presented. CONCLUSIONS The performance metric is relevant for the analysis of the impact of COVID-19 control measures. This can help caregivers and policymakers identify effective control measures and reduce cases of death due to COVID-19. The interactive web visualizer provides easily digested and quick feedback to augment decision-making processes in the COVID-19 response measures evaluation. CLINICALTRIAL Not Applicable

scholarly journals Effectiveness of Epidemic Preventive Policies and Hospital Strategies in Combating COVID-19 Outbreak in Taiwan

2021 ◽  
Vol 18 (7) ◽  
pp. 3456
Author(s):  
Ting Wan Tan ◽  
Han Ling Tan ◽  
Man Na Chang ◽  
Wen Shu Lin ◽  
Chih Ming Chang
Keyword(s):  
Mortality Rate ◽  
Incidence Rate ◽  
Risk Ratio ◽  
Early Stage ◽  
Control Measures ◽  
Polymerase Chain Reaction Test ◽  
Effective Control ◽  
Nasopharyngeal Swab ◽  
Preventive Strategies ◽  
Epidemic Control

(1) Background: The implementation of effective control measures in a timely fashion is crucial to control the epidemic outbreak of COVID-19. In this study, we aimed to analyze the control measures implemented during the COVID-19 outbreak, as well as evaluating the responses and outcomes at different phases for epidemic control in Taiwan. (2) Methods: This case study reviewed responses to COVID-19 and the effectiveness of a range of control measures implemented for epidemic control in Taiwan and assessed all laboratory-confirmed cases between 11 January until 20 December 2020, inclusive of these dates. The confirmation of COVID-19 infection was defined as the positive result of a reverse-transcriptase–polymerase-chain-reaction test taken from a nasopharyngeal swab. Test results were reported by the Taiwan Centers for Disease Control. The incidence rate, mortality rate, and testing rate were compiled, and the risk ratio was provided to gain insights into the effectiveness of prevention measures. (3) Results and Discussion: This study presents retrospective data on the COVID-19 incidence rate in Taiwan, combined with the vital preventive control measures, in a timeline of the early stage of the epidemic that occurred in Taiwan. The implementation of multiple strategy control measures and the assistance of technologies to control the COVID-19 epidemic in Taiwan led to a relatively slower trend in the outbreak compared to the neighboring countries. In Taiwan, 766 confirmed patients were included, comprised of 88.1% imported cases and 7.2% local transmission cases, within the studied period. The incidence rate of COVID-19 in Taiwan during the studied period was 32 per million people, with a mortality rate of 0.3 per million people. Our analysis showed a significantly raised incidence risk ratio in the countries of interest in comparison to Taiwan during the study period; in the range of 1.9 to 947.5. The outbreak was brought under control through epidemic policies and hospital strategies implemented by the Taiwan Government. (4) Conclusion: Taiwan’s preventive strategies resulted in a drastically lower risk for Taiwan nationals of contracting COVID-19 when new pharmaceutical drug or vaccines were not yet available. The preventive strategies employed by Taiwan could serve as a guide and reference for future epidemic control strategies.

scholarly journals Molecular Identification of Mushroom Species in Italy: An Ongoing Project Aimed at Reinforcing the Control Measures of an Increasingly Appreciated Sustainable Food

2020 ◽  
Vol 13 (1) ◽  
pp. 238
Author(s):  
Alice Giusti ◽  
Enrica Ricci ◽  
Laura Gasperetti ◽  
Marta Galgani ◽  
Luca Polidori ◽  
...  
Keyword(s):  
Selection Process ◽  
Winning Strategy ◽  
Control Measures ◽  
Effective Control ◽  
Mushroom Poisoning ◽  
Clinical Samples ◽  
Similar Species ◽  
Mushroom Species ◽  
Ongoing Research ◽  
Genotypic Analysis

Proper investment in mushroom production (farming and wild mushroom picking activities) may represent a winning strategy for many countries, including Italy, to better face the problems of food security and environmental impact, and to break away from imports, enhancing the local products. However, the risk related to the consumption of poisoning species requires governments to implement or reinforce effective control measures to protect consumers. Mushroom identification by phenotype observation is hardly applicable if morphologically-similar species, non-whole specimens, or clinical samples are involved. Genotypic analysis is a valid alternative. An ongoing research project involving the Experimental Zooprophylactic Institute of Lazio and Tuscany, the regional Mycological Inspectorate, the Tuscany Mycological Groups Association, and the Department of Veterinary Sciences of the University of Pisa aims to reinforce the collaboration among institutions for the management of mushroom poisoning. The core’s project aims to develop an internal genetic database to support the identification of wild and cultivated mushroom species in the Italian territory. The database will include Internal Transcribed Spacer (ITS) sequences retrieved from official databases (the NCBI GenBank and the BOLD system) which are considered to be reliable, after a proper selection process, and sequences from specimens collected directly and identified by expert mycologists. Once it is validated, the database will be available and further implementable by the official network of national laboratories.

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