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Li X.,Tsinghua University | Wu Y.,Tsinghua University | Yao X.,Guangzhou Environmental Monitoring Center | Zhang S.,Tsinghua University | And 2 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2012

The short transient loaded mode (IG195) test can improve the efficiency of identifying high emitters in inspection/maintenance (I/M) programs. This paper was based on the pilot IG195 test data of light-duty gasoline vehicles (LDGV) in Guangzhou from 2007 to 2009. The percentages of high emitters exceeding the cut points for pre-and post-Euro I (including Euro I) vehicles were 20.1% and 17.6%, respectively. Re-inspection test data showed that 76.0% pre-Euro I and 64.7% post-Euro I high emitters could meet the requirement after proper maintenance. The modified MOBILE5 model was used to estimate the emission factors for LDGV. In 2009, the LDGV in Guangzhou emitted 244 thousand tons of CO, 38 thousand tons of HC and 18 thousand tons of NO x. If all of the vehicles which finally failed the IG195 test could be scrapped, the emissions of CO, HC and NO x can be reduced by 42.0 thousand tons, 5.8 thousand tons and 1.5 thousand tons, respectively, which amount to 17.2%, 15.3% and 8.2% of the total LDGV emissions. If all of the vehicles finally failing IG195 could be replaced by Euro IV models that complied with their emission standards, the emissions of CO, HC and NO x could be reduced by 41.2 thousand tons, 5.7 thousand tons and 1.4 thousand tons, which made up 16.9%, 15.0% and 8.0% of the total LDGV emissions, respectively. Controlling the pre-Euro I and Euro I vehicles was the most effective way in achieving emission reduction benefits by the new I/M program. The two vehicle categories together contributed about 90% of the emission reduction for CO and HC, and 85% for NO x in the I/M program.

Fan Q.,Sun Yat Sen University | Shen C.,Sun Yat Sen University | Wang X.,Sun Yat Sen University | Li Y.,Guangzhou Research Institute of Environmental Protection | And 4 more authors.
Asia-Pacific Journal of Atmospheric Sciences | Year: 2013

A strong dust-storm (23-25 April, 2009) occurred in the provinces of Inner Mongolia, Gansu, and Shanxi, North China. Cities along the storm path (from north to south: Xi'ning, Lanzhou, Chengdu, Changsha, and Guangzhou) all experienced a sharp increase in particle matter (PM10) concentration. This is the first case that an Asian dust storm hit Guangzhou in Southern China. The impacts of dust storm on the characteristics of PM were investigated using samples collected in Guangzhou during 27-29 April, 2009. In addition, the mass concentration and chemical composition during a normal non-dust period (12-14 May, 2009) were compared with those in dust period. The results show that the concentration of PM10 during the dust episode (0.231 mg m -3) was twice higher than that in the non-dust episode (0.103 mg m-3). Chemical analysis showed that concentrations of metal elements, enrichment factors of metal elements, and soluble ions during the dust episode were very different from those of non-dust. The total concentration of metal elements content in PM10 was 53.5 μg m-3 in the dust episode, which is about two times higher than that in non-dust episode (28.5 μg m-3). Increases in concentrations of Na, Ti, Zn, Cu, and Cr ranged from zero to 100% during the dust episode. However, the enrichment factors in non-dust episode were higher than that in dust-storm period, indicating that the above five chemicals originated mainly from local sources in Guangzhou. The concentrations of K, Mg, Al, Fe, Mn, V, and Co increased by over 100% in the dust episode, indicating their origins of remote sources. In the dust period, some water-soluble ions increased in PM10, but the main components in PM10 were SO4 -, NO3 - and NH4 +. At last, we assessed the sources of dusts by analyzing synoptic situation and back trajectories of air mass in Guangzhou, and demonstrated that the main source of the dust storm was from Mongolia. © 2013 The Korean Meteorological Society and Springer.

Chen W.,Sun Yat Sen University | Wang X.,Sun Yat Sen University | Zhou S.,Sun Yat Sen University | Cohen J.B.,Sun Yat Sen University | And 8 more authors.
Aerosol and Air Quality Research | Year: 2016

A one-year field experiment was conducted in 2013 at an urban and suburban site in Guangzhou, Southern China to study the chemical compositions of PM2.5 and reconstruct the IMPROVE Algorithm to investigate the impact of aerosol components on visibility. Annual average PM2.5 mass concentration was 61.3 ± 27.6 and 54.2 ± 29.7 µg m–3 at the urban and suburban site, with organic matter (OM), sulfate (SO4 2–), and nitrate (NO3 –) among the dominant components, accounting for 40.3%, 16.3%, and 8.0% of the PM2.5 mass concentration respectively. Based on the modified IMPROVE Algorithm, the localized Mass Scattering Efficiencies (MSE) for sulfate and nitrate was obtained, with values of 2.16 ± 0.34 m2 g–1 and 2.63 ± 0.66 m2 g–1 at urban site and 2.22 ± 0.31 m2 g–1 and 2.76 ± 0.84 m2 g–1 at suburban site. Hygroscopic growth factors (Gf) for OM and EC were also taken into consideration with average values of 1.28 ± 0.13 m2 g–1 and 1.15 ± 0.11 m2 g–1 at the urban site and 1.18 ± 0.09 m2 g–1 and 1.10 ± 0.09 m2 g–1 at the suburban site. The estimated total light extinction coefficient was 294.7 ± 106.9 and 255.8 ± 119.0 Mm–1 at the urban and suburban site, with OM, SO4 2– and NO3 – contributing 41.7%, 16.5% and 11.5% at the urban site, and 42.1%, 21.3% and 9.1% at the suburban site. Secondary water-soluble ions and OM as a whole was becoming increasingly vital under polluted conditions, with nitrate in particular being more important under heavily polluted conditions in Guangzhou. © Taiwan Association for Aerosol Research.

Zhang J.,Sun Yat Sen University | Zhang J.,Guangzhou Environmental Monitoring Center | Hu J.,Sun Yat Sen University | Wang X.,Sun Yat Sen University
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2014

This paper mainly evaluated the ability of Ensemble Optimal Interpolation Data Assimilation Method (EnOI) in modifying the pollutants concentration forecast field in MM5-STEM air quality numerical model. Optimal settings of localization scale (L) and empirical coefficient (α) of NO2, SO2 and PM10 were acquired by sensitivity tests respectively. Assimilation results under these coefficient settings were analyzed, the results showed that EnOI had a good performance in the data assimilation experiments of NO2, SO2 and PM10, with RMSE decreasing percentage of 33%, 32% and 42%, respectively. The proportion of verification stations with decreased RMSE were 86%, 84% and 91%, respectively, which proved that EnOI produced a pollutant concentration forecast field closer to the true situation, therefore can be effectively applied in air quality modeling in the PRD.

Zhang Y.,CAS Guangzhou Institute of Geochemistry | Wang X.,CAS Guangzhou Institute of Geochemistry | Li G.,CAS Guangzhou Institute of Geochemistry | Li G.,University of Chinese Academy of Sciences | And 14 more authors.
Atmospheric Environment | Year: 2015

Motor vehicles contribute primarily and secondarily to air quality problems due to fine particle (PM2.5) and ozone (O3) pollution in China's megacities. Characterizing vehicle emission with the rapid change of vehicle numbers and fleet compositions is vital for both bottom-up emission survey and top-down source apportioning. To obtain emission factors (EFs) of PM2.5, carbonaceous aerosols and trace gases for road vehicles, in urban Guangzhou we conducted a field campaign in 2014 in the Zhujiang Tunnel, a heavily burdened tunnel with about 40,000 motor vehicles passing through each of its two separated bores per day. PM2.5 and volatile organic compounds (VOCs) were sampled for offline analysis while trace gases including SO2, NOx and CO were measured online and in situ. An eddy covariance system with an integrated 3-D sonic anemometer was also adopted to measure CO2 and winds inside the tunnel. We recorded an average fleet composition of 61% light-duty gasoline vehicles (LDVs) + 12% heavy-duty diesel vehicles (HDVs) + 27% liquefied petroleum gas vehicles (LPGVs), and EFs of 82.7 ± 28.3, 19.3 ± 4.7 and 13.3 ± 3.3 mg veh-1 km-1, respectively, for PM2.5, organic carbon (OC) and elemental carbon (EC). These EFs were respectively 23.4%, 18.3% and 72.3% lower when compared to that measured in the same tunnel in 2004. EFs of PM2.5, OC and EC were higher at night time (148 ± 126, 29 ± 24 and 21 ± 18 mg veh-1 km-1, respectively) due to significantly elevated fractions of HDVs in the traffic fleets. An average ratio of OC to EC 1.45 from this tunnel study was much higher than that of ~0.5 in previous tunnel studies. The EFs of SO2, NOx, CO, CO2 and NMHCs for road traffic were also obtained from our tunnel tests, and they were 20.7 ± 2.9, (1.29 ± 0.2)E+03, (3.10 ± 0.68)E+03, (3.90 ± 0.49)E+05, and 448 ± 39 mg veh-1 km-1, respectively. © 2015 Elsevier Ltd.

Zhang Y.,CAS Guangzhou Institute of Geochemistry | Zhang Y.,University of California at Irvine | Wang X.,CAS Guangzhou Institute of Geochemistry | Blake D.R.,University of California at Irvine | And 10 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2012

In the second half of 2008 China's highly industrialized Pearl River Delta (PRD) region was hard-hit by the financial crisis (FC). This study reports volatile organic compounds measured in the PRD during November-December in both 2007 before the FC and 2008 after the FC. While total mixing ratios of non-methane hydrocarbons (NMHCs) on average were only about 7% lower from 40.2 ppbv in 2007 to 37.5 ppbv in 2008, their ozone formation potentials (OFPs) dropped about 30%, resulting from about 55% plummet of aromatic hydrocarbons (AHs) against a greater than 20% increase of total alkanes/alkenes. The elevated alkanes and alkenes in 2008 could be explained by greater emissions from vehicle exhausts and LPG combustion due to rapid increase of vehicle numbers and LPG consumption; the drop of AHs could be explained by reduced emissions from industries using AH-containing solvents due to the influence of the FC, as indicated by much lower ratios of toluene to benzene and of xylenes/ trichloroethylene/tetrachloroethylene to carbon monoxide (CO) in 2008. Source apportionment by positive matrix factorization (PMF) also revealed much less contribution of industry solvents to total anthropogenic NMHCs and particularly to toluene and xylenes in 2008 than in 2007. Based on PMF reconstructed source contributions, calculated OFPs by industrial emissions were responsible for 40.8% in 2007 in contrast to 18.4% in 2008. Further investigation into local industry output statistics suggested that the plummet of AHs in 2008 should be attributed to small enterprises, which contributed largely to ambient AHs due to their huge numbers and non-existent emission treatment, but were much more influenced by the FC. © 2012. American Geophysical Union. All Rights Reserved.

Wang X.,CAS Guangzhou Institute of Geochemistry | Ding X.,CAS Guangzhou Institute of Geochemistry | Fu X.,CAS Guangzhou Institute of Geochemistry | Fu X.,University of Chinese Academy of Sciences | And 7 more authors.
Journal of Environmental Sciences | Year: 2012

During November-December 2010 aerosol scattering coefficients were monitored using a single-waved (525 nm) Nephelometer at a regional monitoring station in the central Pearl River Delta region and 24-hr fine particle (PM 2.5) samples were also collected during the period using quartz filters for the analysis of major chemical components including organic carbon (OC), elemental carbon (EC), sulfate, nitrate and ammonium. In average, these five components accounted for about 85% of PM 2.5 mass and contributed 42% (OC), 19% (SO 4 2-), 12% (NO 3 -), 8.4% (NH 4 +) and 3.7% (EC), to PM 2.5 mass. A relatively higher mass scattering efficiency of 5.3 m 2/g was obtained for fine particles based on the linear regression between scattering coefficients and PM2.5 mass concentrations. Chemical extinction budget based on IMPROVE approach revealed that ammonium sulfate, particulate organic matter, ammonium nitrate and EC in average contributed about 32%, 28%, 20% and 6% to the light extinction coefficients, respectively. © 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Gao B.,CAS Guangzhou Institute of Geochemistry | Gao B.,South China Institute of Environmental Sciences | Wang X.-M.,CAS Guangzhou Institute of Geochemistry | Zhao X.-Y.,CAS Guangzhou Institute of Geochemistry | And 10 more authors.
Atmospheric Environment | Year: 2015

24-hPM2.5 samples were simultaneously collected at six sites in a subtropical city of South China during November-December, 2009. Particle-phase concentrations of polycyclic aromatic hydrocarbons (PAHs) and organic tracers such as hopanes for vehicular emissions (VE), levoglucosan for biomass burning (BB) and picene for coal combustion (CC) were determined. Meanwhile, their gas-phase concentrations were calculated from gas/particle (G/P) partitioning theory using the particle-phase concentrations. The 4 ring PAHs (fluoranthene to chrysene) had lower particle-phase fractions (10%-79%) than other species. Estimated BaPeq and lifetime cancer risk for particle-only (P-only) vs gas+particle (G+P) data sets showed similar values, indicating PAHs with 5-7 rings dominated the carcinogenicity of PAHs. Positive Matrix Factorization (PMF) was applied on both P-only and G+P data sets to estimate the source contributions to PAHs and their toxicity. Three common sources were identified: VE, BB and CC, with CC as the most significant source for both particulate (58%) and total (G+P, 40%) PAHs. While CC exhibited consistent contributions to BaPeq for P-only (66%) vs G+P (62%) solutions, VE and BB contributions were under- and overestimated by 68% and 47%, respectively by the P-only solution, as compared to the G+P solution. The results provide an insight on the impact of G/P partitioning on the source apportionment of PAHs and their toxicity. © 2014 Elsevier Ltd.

Zhou Y.,Guangzhou University | Hu G.,Guangzhou University | Wang D.,Second Hospital of Liwan District of Guangzhou | Wang S.,Guangzhou Environmental Monitoring Center | And 13 more authors.
BMJ (Online) | Year: 2010

Objective: To evaluate the effects of a community based integrated intervention for early prevention and management of chronic obstructive pulmonary disease (COPD) in China. Design: Cluster randomised controlled trial. Setting: Eight healthcare units in two communities. Participants: Of 1062 people aged 40-89, 872 (101 with COPD and 771 without COPD) who fulfilled the inclusion and exclusion criteria were allocated to the intervention or the usual care programmes. Intervention: Participants randomly assigned to integrated intervention (systematic health education, intensive and individualised intervention, treatment, and rehabilitation) or usual care. Main outcome measures: Annual rate of decline in forced expiratory rate in one second (FEV1) before use of bronchodilator. Results: Annual rate of decline in FEV1 was significantly lower in the intervention community than the control community, with an adjusted difference of 19 ml/year (95% confidence interval 3 to 36) and 0.9% (0.1% to 1.8%) of predicted values (all P<0.05), as well as a lower annual rate of decline in FEV1/FVC (forced vital capacity) ratio (adjusted difference 0.6% (0.1% to 1.2%) P=0.029). There were also higher rates of smoking cessation (21% v 8%, P<0.004) and lower cumulative death rates from all causes (1% v 3%, P<0.009) in the intervention community than in the control community during the four year follow-up. Improvements in knowledge of COPD and smoking hazards, outdoor air quality, environmental tobacco smoke, and working conditions were also achieved (all P<0.05). The difference in cumulative incidence rate of COPD (both around 4%) and cumulative death rate from COPD (2% v 11%) did not reach significance between the two communities. Conclusions: A community based integrated intervention can have a significant impact on the prevention and management of COPD, mainly reflected in the annual rate of decline in FEV1. Trial registration: Chinese Clinical Trials Registration (ChiCTR-TRC-00000532).

Zeng Y.-J.,Guangzhou Environmental Monitoring Center | Zhou Z.-J.,Guangzhou Environmental Monitoring Center | Zhao Q.-X.,Guangdong Province Research Center for Geoanalysis
Huanjing Kexue/Environmental Science | Year: 2015

Adsorption and desorption experiments, pot experiments and characterization test were performed to investigate the immobilization effect and mechanism of the smectite-OR-SH compound for reducing cadmium uptake by plants in contaminated soils. The results showed that the saturated adsorption capacity for the adsorption of Cd2+ on smectite raised distinctly after functionalized. The adsorption of Cd2+ on smectite-OR-SH compound was very stable and it was difficult for Cd2+ to be desorbed from it.Crop yields promoted differently in original soil, Cd 3 mg·kg-1 soil and Cd 10 mg·kg-1 soil after adding the smectite-OR-SH compound. And the cadmium content of the cabbage reduced 61.00%, 62.10% and 83.73% respectively compare with the control. Characterization test analysis showed that Cd was adsorbed by the compound successfully and ligand interaction occurred between Cd and the thiol group. Floc amount on the compound surface increased correspondingly. In addition to electrostatic adsorption, ion exchange and hydroxyl ligand adsorption, the reaction mechanism of smectite-OR-SH compound with Cd was mainly sulfhydryl ligand adsorption. ©, 2015, Science Press. All right reserved.

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