A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides(NO_(x))mitigation.TiO_(2)-based photoc...A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides(NO_(x))mitigation.TiO_(2)-based photocatalytic coating PC-C film with crystallized size of around 5–6 nm was synthesized with the peptization of H_(2)O_(2).The PC-C coating possesses a super-hydrophilicity surface and is proven to have a NO_(x)degradation rate of 46.8%with an optimum pH level of 7.In addition,the PC-C coating presents a promising photocatalytic NO_(x)degradation compared with other commercially available coating products and P25 when applied on two building materials of poly-methyl methacrylate(PMMA)and concrete surface.A weather resistance simulation and a 180-day on-site field trial were carried out the attenuation effects of photocatalytic coating applied in outdoor exposure.Based on epidemiological estimation and field investigation,hospital admissions for respiratory diseases(HARD)and mortality cases(MC)could be reduced with the application of PC-C coating along the street canyon.This work demonstrates the feasibility of air pollution control measures for the local roadside NO_(x)using photocatalytic technology,offering promising health benefits with environmental remediation.展开更多
Study of Air Quality Objectives(AQOs)and long-term changes of air pollution plays a decisive role in formulating and refining pollution control strategies.In this study,10-year variations of six major air pollutants w...Study of Air Quality Objectives(AQOs)and long-term changes of air pollution plays a decisive role in formulating and refining pollution control strategies.In this study,10-year variations of six major air pollutants were analyzed at seven monitoring sites in Hong Kong region.The continuous decrease of annual averaged concentrations of NO_(2),SO_(2),CO,PM_(2.5)and PM_(10)and numbers of days with severe pollution conditions validated the efficiency of the series of air pollution control schemes implemented by the Hong Kong region government.However,there is still a big gap to meet the ultimate targets described by the World Health Organization.Besides,the concentration of O_(3)at roadside and urban stations increased by 135%±25%and 37%±18%from 2011 to 2020,respectively,meanwhile the highest 8 hr averaged O_(3)concentration was observed as 294μg/m^(3)at background station in 2020,which pointed out the increasing ozone pollution in Hong Kong region.There was a great decrease in the annual times of air quality health index(AQHI)laying in“high”,“very high”and“serious”categories from 2011 to 2020 with the decrease rate of 89.70%,91.30%and 89.74%at roadside stations,and 79.03%,95.98%and 72.73%at urban stations,respectively.Nevertheless,the number of days categorized as“high”or above at roadside station was twice more than that in the urban station during the past ten years.Thus,more policies and attentions should be given to the roadside air quality and its adverse health effect to pedestrians on street.展开更多
Indoor dusffall samples were collected in Pit 1 and Pit 2 of Emperor Qin＇s Terra-cotta Warriors and Horses Museum in Xi＇an, Shaanxi Province, China. The morphological and elemental analysis for long-term （〉10 year...Indoor dusffall samples were collected in Pit 1 and Pit 2 of Emperor Qin＇s Terra-cotta Warriors and Horses Museum in Xi＇an, Shaanxi Province, China. The morphological and elemental analysis for long-term （〉10 years） and short-term （～0.5 year） dusffall particles and lacquer pieces on the faces of partly assembled warriors were performed with scanning electron microscopy with energy dispersive X-ray spectrometer （SEM/EDX）. The results showed that the majority of dusffall samples appeared to be composed of mineral dust particles, fly ash, and biological particles with different elemental compositions. Most of the mineral particles had irregular shapes with smooth edges. Small floccules of calcium sulfate were more frequently observed in long-term dusffall samples than in short-term samples, implying a progressive chemical reaction between continuous dusffall particles and atmospheric sulfur dioxide. Crystals of calcium sulfate were also found near pits on both inner and outer surfaces of lacquer pieces, revealing an acid chemical reaction between sulfur dioxide and lacquer material as the cause of the formation of erosion pits and cracks on surface of lacquer pieces.展开更多
The time series of indoor and outdoor particle number concentrations in a naturally ventilated residential building in Xi＇an were tested simultaneously for 7 days in summer. The relationships between indoor and outdo...The time series of indoor and outdoor particle number concentrations in a naturally ventilated residential building in Xi＇an were tested simultaneously for 7 days in summer. The relationships between indoor and outdoor concentrations were examined and discussed, and linear regression analysis was employed to correlate the indoor and outdoor concentrations. The diurnal cycles of indoor and outdoor particle concentrations of different particle size ranges all showed positive correlations between indoor and outdoor number concentrations, The I/O ratios of number concentrations varied with the increase of particle size in the range of 0.89 （±0.19） to 0.99 （±0.15）.展开更多
基金supported by the collaborative research project from Ove Arup&Partners Hong Kong Limited(No.P0038294)Theme-based Research Schemes(Nos.T31-603/21-N and T24504/17-N)of Research Grants Council,Hong Kong+2 种基金supported by the General Research Fund,Research Grants Council of Hong Kong Government(No.18300920)Dean’s Research Fund(No.04738),FLASS,EdUHKsupports from the Highway Department of Hong Kong,SAR for the field study part of this work。
文摘A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides(NO_(x))mitigation.TiO_(2)-based photocatalytic coating PC-C film with crystallized size of around 5–6 nm was synthesized with the peptization of H_(2)O_(2).The PC-C coating possesses a super-hydrophilicity surface and is proven to have a NO_(x)degradation rate of 46.8%with an optimum pH level of 7.In addition,the PC-C coating presents a promising photocatalytic NO_(x)degradation compared with other commercially available coating products and P25 when applied on two building materials of poly-methyl methacrylate(PMMA)and concrete surface.A weather resistance simulation and a 180-day on-site field trial were carried out the attenuation effects of photocatalytic coating applied in outdoor exposure.Based on epidemiological estimation and field investigation,hospital admissions for respiratory diseases(HARD)and mortality cases(MC)could be reduced with the application of PC-C coating along the street canyon.This work demonstrates the feasibility of air pollution control measures for the local roadside NO_(x)using photocatalytic technology,offering promising health benefits with environmental remediation.
基金supported by the Research Grants Council of Hong Kong Government(Project No.T24/504/17 and T31-603/21-N)he Environment and Conservation Fund of Hong Kong Governmentt(Project No.ECF 63/2019).
文摘Study of Air Quality Objectives(AQOs)and long-term changes of air pollution plays a decisive role in formulating and refining pollution control strategies.In this study,10-year variations of six major air pollutants were analyzed at seven monitoring sites in Hong Kong region.The continuous decrease of annual averaged concentrations of NO_(2),SO_(2),CO,PM_(2.5)and PM_(10)and numbers of days with severe pollution conditions validated the efficiency of the series of air pollution control schemes implemented by the Hong Kong region government.However,there is still a big gap to meet the ultimate targets described by the World Health Organization.Besides,the concentration of O_(3)at roadside and urban stations increased by 135%±25%and 37%±18%from 2011 to 2020,respectively,meanwhile the highest 8 hr averaged O_(3)concentration was observed as 294μg/m^(3)at background station in 2020,which pointed out the increasing ozone pollution in Hong Kong region.There was a great decrease in the annual times of air quality health index(AQHI)laying in“high”,“very high”and“serious”categories from 2011 to 2020 with the decrease rate of 89.70%,91.30%and 89.74%at roadside stations,and 79.03%,95.98%and 72.73%at urban stations,respectively.Nevertheless,the number of days categorized as“high”or above at roadside station was twice more than that in the urban station during the past ten years.Thus,more policies and attentions should be given to the roadside air quality and its adverse health effect to pedestrians on street.
基金This research was supported by the National Science Foundation of China （No. 40121303） was supported by the National Basic Research Program of China （G2004CB720200）.
文摘Indoor dusffall samples were collected in Pit 1 and Pit 2 of Emperor Qin＇s Terra-cotta Warriors and Horses Museum in Xi＇an, Shaanxi Province, China. The morphological and elemental analysis for long-term （〉10 years） and short-term （～0.5 year） dusffall particles and lacquer pieces on the faces of partly assembled warriors were performed with scanning electron microscopy with energy dispersive X-ray spectrometer （SEM/EDX）. The results showed that the majority of dusffall samples appeared to be composed of mineral dust particles, fly ash, and biological particles with different elemental compositions. Most of the mineral particles had irregular shapes with smooth edges. Small floccules of calcium sulfate were more frequently observed in long-term dusffall samples than in short-term samples, implying a progressive chemical reaction between continuous dusffall particles and atmospheric sulfur dioxide. Crystals of calcium sulfate were also found near pits on both inner and outer surfaces of lacquer pieces, revealing an acid chemical reaction between sulfur dioxide and lacquer material as the cause of the formation of erosion pits and cracks on surface of lacquer pieces.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 50578034, Grant No. 40475047）Shanghai Educational Development Foundation Titled ＂Shuguang Project＂, P.R. China （Grant No. 03SG30）.
文摘The time series of indoor and outdoor particle number concentrations in a naturally ventilated residential building in Xi＇an were tested simultaneously for 7 days in summer. The relationships between indoor and outdoor concentrations were examined and discussed, and linear regression analysis was employed to correlate the indoor and outdoor concentrations. The diurnal cycles of indoor and outdoor particle concentrations of different particle size ranges all showed positive correlations between indoor and outdoor number concentrations, The I/O ratios of number concentrations varied with the increase of particle size in the range of 0.89 （±0.19） to 0.99 （±0.15）.
