This page has only limited features, please log in for full access.
The highly reactive nature of biogenic volatile organic compounds (BVOCs) impacts the biosphere by acting as a precursor of ozone and aerosols that influence air quality and climate. Here, we assess the influence of BVOCs and their oxidation products on ozone formation and to submicron secondary organic aerosol (SOA) mass in a subtropical forest. A high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) was employed for the continuous measurement of VOCs. Isoprene, monoterpene, and sesquiterpene mixing ratios in the forest were 0.23, 0.22, and 0.03 ppb, respectively. The total ozone formation potential (OFP) of the terpenes was 12.8 μg m−3, which accounted for only 5.6% of the total OFP. Particle phase bound oxidation products were characterized using a thermal-desorption PTR-ToF-MS. Mass spectra analysis revealed the presence pinonaldehyde, pinonic, norpinonic, and pinic acid in both gas and particle phase. The overall daytime (nighttime) mixing ratio of the oxidized BVOCs in gas phases was 0.062(0.023) ppbv. On the other hand, the mean fraction of the four monoterpene oxidation products in condensed phase was estimated at 42%. Overall, the results of this study evidenced quantitatively the contribution of BVOCs to the total reactivity and SOA mass in the subtropical forest.
Christian Salvador; Charles Chou; Tse-Tsung Ho; Chao-Yang Tsai; Tsung-Ming Tsao; Ming-Jer Tsai; Ta-Chen Su. Contribution of Terpenes to Ozone Formation and Secondary Organic Aerosols in a Subtropical Forest Impacted by Urban Pollution. Atmosphere 2020, 11, 1232 .
AMA StyleChristian Salvador, Charles Chou, Tse-Tsung Ho, Chao-Yang Tsai, Tsung-Ming Tsao, Ming-Jer Tsai, Ta-Chen Su. Contribution of Terpenes to Ozone Formation and Secondary Organic Aerosols in a Subtropical Forest Impacted by Urban Pollution. Atmosphere. 2020; 11 (11):1232.
Chicago/Turabian StyleChristian Salvador; Charles Chou; Tse-Tsung Ho; Chao-Yang Tsai; Tsung-Ming Tsao; Ming-Jer Tsai; Ta-Chen Su. 2020. "Contribution of Terpenes to Ozone Formation and Secondary Organic Aerosols in a Subtropical Forest Impacted by Urban Pollution." Atmosphere 11, no. 11: 1232.
Dust particles are effective ice nuclei and are known to affect precipitation. Here, the possible impacts of mineral dust on summertime cloud and precipitation over the Taiwan region are investigated through analysis of 25 years (1989 – 2013) of multiple observational and modeling datasets. Due to the unique mechanism, typhoon precipitations are excluded from this study. Statistical methods (partial correlation and stratification) are used to untangle the influences of dust from the co‐varying meteorological conditions (water vapor, horizontal wind, sea surface temperature, and moisture flux). The results suggest a statistically significant positive correlation between non‐typhoon precipitation and the number concentration of dust particles larger than 0.5 μm (Nd) in July and August in the regions with heavy precipitation. From clean (Nd= ~0.008 cm‐3) to dusty days (Nd=~0.2 cm‐3), averaged ice (liquid) water paths and precipitation increase by ~25% (~20%) and ~70% over the orographic region, and vertically, ~30% more cloud ice content is generated at ~ 350 hPa (T = ~−20°C), enhancing the development of the mixed‐phase cloud and precipitation. The results also indicate the critical role of the atmospheric water vapor in the responses of precipitation to Nd, with precipitation increasing more significantly with Nd in higher water vapor circumstances.
Yanda Zhang; Fangqun Yu; Gan Luo; Jen‐Ping Chen; Charles C.‐K. Chou. Impact of Mineral Dust on Summertime Precipitation Over the Taiwan Region. Journal of Geophysical Research: Atmospheres 2020, 125, 1 .
AMA StyleYanda Zhang, Fangqun Yu, Gan Luo, Jen‐Ping Chen, Charles C.‐K. Chou. Impact of Mineral Dust on Summertime Precipitation Over the Taiwan Region. Journal of Geophysical Research: Atmospheres. 2020; 125 (19):1.
Chicago/Turabian StyleYanda Zhang; Fangqun Yu; Gan Luo; Jen‐Ping Chen; Charles C.‐K. Chou. 2020. "Impact of Mineral Dust on Summertime Precipitation Over the Taiwan Region." Journal of Geophysical Research: Atmospheres 125, no. 19: 1.
Anthropogenic emissions of aerosols and trace gases from East Asia have significant impacts on air quality and climate on regional and global scales. We conducted intensive measurements of aerosols at a remote site (Cape Fuguei; 25.30°N, 121.54°E) in Taiwan in the spring of 2017, focusing on the chemical composition and mixing state of aerosols in Asian outflow. A laser‐induced incandescence–mass spectrometric analyzer (LII‐MS) was used to measure the chemical composition of aerosols internally or externally mixed with black carbon (BC). Offline analysis by transmission electron microscopy (TEM) was used to characterize the mixing state of aerosols. The observation period was classified into long‐range transport (LRT) periods and local pollution (LP) periods on the basis of cluster analysis of three‐day backward trajectories. LII‐MS data showed that the average mass fractions of sulfate and nitrate internally mixed with BC were 7 ± 13% and 11 ± 15%, respectively, for LRT periods. By TEM analysis of selected samples from LRT periods, the number fraction of aerosol particles internally mixed with BC was estimated to be 5–36% for core‐shell types and 5–23% for attached types. Factors affecting the differences between LII‐MS and TEM measurements are discussed. TEM data indicated the presence of a variety of aerosol mixing states in widespread regional pollution transported 500–1,000 km downwind of emission sources. Our results provide new constraints for three‐dimensional models that might resolve the mixing state of aerosol particles, which are critical for accurately estimating the radiative impact of BC.
Cuizhi Sun; Kouji Adachi; Kentaro Misawa; Hing Cho Cheung; Charles C.‐K. Chou; Nobuyuki Takegawa. Mixing State of Black Carbon Particles in Asian Outflow Observed at a Remote Site in Taiwan in the Spring of 2017. Journal of Geophysical Research: Atmospheres 2020, 125, 1 .
AMA StyleCuizhi Sun, Kouji Adachi, Kentaro Misawa, Hing Cho Cheung, Charles C.‐K. Chou, Nobuyuki Takegawa. Mixing State of Black Carbon Particles in Asian Outflow Observed at a Remote Site in Taiwan in the Spring of 2017. Journal of Geophysical Research: Atmospheres. 2020; 125 (16):1.
Chicago/Turabian StyleCuizhi Sun; Kouji Adachi; Kentaro Misawa; Hing Cho Cheung; Charles C.‐K. Chou; Nobuyuki Takegawa. 2020. "Mixing State of Black Carbon Particles in Asian Outflow Observed at a Remote Site in Taiwan in the Spring of 2017." Journal of Geophysical Research: Atmospheres 125, no. 16: 1.
Dust particles are effective ice nuclei and are known to affect precipitation. Here, the possible impacts of mineral dusts on summertime cloud and precipitation over the Taiwan region are investigated through analysis of 25 years (1989 – 2013) of multiple observational and modeling datasets. Due to the unique mechanism, typhoon precipitations are excluded in this study. Statistical methods are used to untangle the influences of dust from the co-varying water vapor conditions. The results suggest a statistically significant positive correlation between non-typhoon precipitation and number concentration of dust particles larger than 0.5 µm () in July and August in the regions with heavy precipitation. From clean (0.008 cm) to dusty days (0.2 cm), averaged ice (liquid) water paths and precipitation increase by ~25% (~20%) and ~70% over the orographic region, and vertically, ~30% more cloud ice content is generated at ~ 350 hPa (T = ~−20℃), enhancing the development of the mixed-phase cloud and precipitation. The results also indicate critical role of the atmospheric water vapor in the responses of precipitation to , with precipitation increasing more significantly with in higher water vapor circumstances.
Yanda Zhang; Fangqun Yu; Gan Luo; Jen-Ping Chen; Charles C.-K. Chou. Impact of mineral dust on summertime precipitation over the Taiwan region. 2020, 1 .
AMA StyleYanda Zhang, Fangqun Yu, Gan Luo, Jen-Ping Chen, Charles C.-K. Chou. Impact of mineral dust on summertime precipitation over the Taiwan region. . 2020; ():1.
Chicago/Turabian StyleYanda Zhang; Fangqun Yu; Gan Luo; Jen-Ping Chen; Charles C.-K. Chou. 2020. "Impact of mineral dust on summertime precipitation over the Taiwan region." , no. : 1.
Organonitrates (ONs) are an important component of atmospheric aerosols that signify the perturbation of nitrogen oxides (NOx) pollution in the remote atmosphere. This study investigated the mass concentration and molecular composition of ONs in submicron particulate matters (PM1) at a subtropical forest site (Xitou), which located downwind the Taichung metropolis in the Central Taiwan. Here we showed that transport of urban air pollution with local circulations caused elevation in the ambient concentration of ONs in the forested area. In addition, the levels of ONs were positively correlated with ozone mixing ratio and were negatively correlated with the relative humidity, suggesting that the ONs were regulated by photochemistry and hydrolysis. The results also showed that the mass concentration of the ONs was significantly correlated with the number density of nanoparticles (d < 100 nm), implying the role of ONs in the formation and/or growth processes of atmospheric aerosols. Mass spectra analysis revealed five major ONs, which were characterized by the molecular skeletons of either isoprene or monoterpenes. The molecular profiles suggested that the reactions between nitrate radicals and biogenic volatile organic compounds (BVOCs) significantly contributed to the formation of ONs, which thereby represented a major sink of the functional BVOCs in the forested area.
Christian Mark Salvador; C.C.-K. Chou; H.-C. Cheung; T.-T. Ho; C.-Y. Tsai; T.-M. Tsao; M.-J. Tsai; T.-C. Su. Measurements of submicron organonitrate particles: Implications for the impacts of NOx pollution in a subtropical forest. Atmospheric Research 2020, 245, 105080 .
AMA StyleChristian Mark Salvador, C.C.-K. Chou, H.-C. Cheung, T.-T. Ho, C.-Y. Tsai, T.-M. Tsao, M.-J. Tsai, T.-C. Su. Measurements of submicron organonitrate particles: Implications for the impacts of NOx pollution in a subtropical forest. Atmospheric Research. 2020; 245 ():105080.
Chicago/Turabian StyleChristian Mark Salvador; C.C.-K. Chou; H.-C. Cheung; T.-T. Ho; C.-Y. Tsai; T.-M. Tsao; M.-J. Tsai; T.-C. Su. 2020. "Measurements of submicron organonitrate particles: Implications for the impacts of NOx pollution in a subtropical forest." Atmospheric Research 245, no. : 105080.
This study investigated isotopic signatures of carbon (C), lead (Pb) and strontium (Sr) in PM2.5 samples collected from two paired sites (urban vs. rural/background) in northern Taiwan during the summer of 2015 and the spring of 2016, respectively. Significant seasonality was revealed in the isotopic signatures of C and Pb, whereas no seasonal difference was observed in 87Sr/86Sr ratio. The values of δ13C, 206Pb/207Pb, and 208Pb/207Pb were more diverse and exhibited local features in summer. However, during the episodes of continental pollution outbreaks in springtime, the δ13C and Pb isotope ratios of PM2.5 shifted and converged consistently toward the documented characteristics of particulate matters in northern China. Moreover, the results showed that the differences in the Pb and Sr isotopic characteristics between the paired urban and rural sites were statistically insignificant, whereas marginally lower δ13C values were observed at the urban site. It was inferred accordingly that a substantial amount of gaseous hydrocarbons emitted in local urban areas could have been converted to secondary organic aerosols with lower δ13C. On the contrary, the consistency in the spatial and temporal variations of mass concentration and isotope ratios of Pb at the two sites suggested that East-Asian continental pollution outbreak was the major source of Pb-containing particles in the northern Taiwan during springtime. It is noteworthy that there was neither seasonal nor spatial differences in the 87Sr/86Sr ratio observed in this study, which suggested that the Sr-containing particles collected in this study could be originating from a common mixture of sources, including not only natural dust but also the anthropogenic emissions, coal-combustion for instance. This investigation upon the C-Pb-Sr isotopic features evidenced the substantial impacts of the continental pollution outbreaks on the aerosol composition and air quality in the downwind areas of the East-Asian winter monsoons.
Chien-Cheng Jung; Charles C.-K. Chou; Chuan-Yao Lin; Chuan-Chou Shen; Yu-Chi Lin; Yi-Tang Huang; Chao-Yang Tsai; Pei-Hsuan Yao; Ci-Rong Huang; Wei-Ru Huang; Mei-June Chen; Shu-Hui Huang; Shuen-Chin Chang. C-Sr-Pb isotopic characteristics of PM2.5 transported on the East-Asian continental outflows. Atmospheric Research 2019, 223, 88 -97.
AMA StyleChien-Cheng Jung, Charles C.-K. Chou, Chuan-Yao Lin, Chuan-Chou Shen, Yu-Chi Lin, Yi-Tang Huang, Chao-Yang Tsai, Pei-Hsuan Yao, Ci-Rong Huang, Wei-Ru Huang, Mei-June Chen, Shu-Hui Huang, Shuen-Chin Chang. C-Sr-Pb isotopic characteristics of PM2.5 transported on the East-Asian continental outflows. Atmospheric Research. 2019; 223 ():88-97.
Chicago/Turabian StyleChien-Cheng Jung; Charles C.-K. Chou; Chuan-Yao Lin; Chuan-Chou Shen; Yu-Chi Lin; Yi-Tang Huang; Chao-Yang Tsai; Pei-Hsuan Yao; Ci-Rong Huang; Wei-Ru Huang; Mei-June Chen; Shu-Hui Huang; Shuen-Chin Chang. 2019. "C-Sr-Pb isotopic characteristics of PM2.5 transported on the East-Asian continental outflows." Atmospheric Research 223, no. : 88-97.
This study investigated the influence of holiday characteristics and numbers of vacation days on the “holiday effect” of three crucial Chinese holidays in Taipei. Surface measurements of NOx, CO, NMHC, O3, SO2, and PM10 from 13 air quality-monitoring stations of the Taiwan Environmental Protection Administration (TEPA) in the Taipei metropolitan area during holiday and non-holiday periods of 1994–2012 were used. All six pollutants were proven to exhibit holiday effects between Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods. However, almost all pollutants exhibited holiday effects for the two other holidays; the exceptions were O3 between Tomb Sweeping Day (TSD) and non-Tomb Sweeping Day (NTSD) periods and CO and PM10 between Mid-Autumn Day (MAD) and non-Mid-Autumn Day (NMAD) periods. Air pollutants, including NOx, CO, NMHC, SO2, and PM10, that exhibited holiday effects had consistently lower concentrations in holiday periods than in non-holiday periods, whereas O3 concentrations were higher in holiday periods than in non-holiday periods. A widespread holiday effect with consistent signs indicates a high degree of urbanization in the study area. Compared with CNY–NCNY and MAD–NMAD periods, the TSD–NTSD period had a considerably lower difference of the titration effect, lower NOx resulting in less ozone destruction, in evening traffic hours and an inconsistent holiday effect in the daytime and nighttime, leading to the lack of O3 holiday effect. Because the MAD period had more nighttime activities than the other two holiday periods did, the MAD–NMAD period lacked CO and PM10 holiday effects. The prevalently higher ratios of CO, NMHC, SO2, and PM10 relative to NOx as a proxy of mobile sources and a lower PM2.5/PM10 ratio in the MAD period than in the CNY and TSD periods indicate different pollution sources oriented from holiday activities. The air pollutants exhibited a weakening trend are all associated with a greater improvement in air quality during the non-holiday periods than the holiday periods, which implies successful air pollution control policies. Holiday effects of NOx, NMHC (p < 0.05), and CO (p < 0.10) are associated with mobile sources; the holiday effects for the three holidays tend to have a strong relation with the number of vacation days in a holiday, indicating that a large reduction of air pollution occurs when a holiday has a high number of vacation days, which probably encourages extensive behavioral changes. Moreover, the aforementioned conditions imply that air pollution control strategies are effective with time; pollution reduction for only 1–2 days may fail to improve ambient air quality. Holiday effects of pollutants emitted during long holiday periods have crucial implications in formulating ozone control strategies in Taiwan and in other countries with similar national or cultural holidays.
Pen-Yuan Chen; Pei-Hua Tan; Charles C.-K. Chou; Yu-Shiuan Lin; Wei-Nai Chen; Chein-Jung Shiu. Impacts of holiday characteristics and number of vacation days on “holiday effect” in Taipei: Implications on ozone control strategies. Atmospheric Environment 2019, 202, 357 -369.
AMA StylePen-Yuan Chen, Pei-Hua Tan, Charles C.-K. Chou, Yu-Shiuan Lin, Wei-Nai Chen, Chein-Jung Shiu. Impacts of holiday characteristics and number of vacation days on “holiday effect” in Taipei: Implications on ozone control strategies. Atmospheric Environment. 2019; 202 ():357-369.
Chicago/Turabian StylePen-Yuan Chen; Pei-Hua Tan; Charles C.-K. Chou; Yu-Shiuan Lin; Wei-Nai Chen; Chein-Jung Shiu. 2019. "Impacts of holiday characteristics and number of vacation days on “holiday effect” in Taipei: Implications on ozone control strategies." Atmospheric Environment 202, no. : 357-369.
The aim of this study was to chemically characterize the fine particulate matter (PM2.5) at a subtropical forest in East Asia under the influences of anthropogenic and biogenic sources and a complex topographic setting. Four seasonal campaigns were conducted at the Xitou Experimental Forest in central Taiwan from the winter of 2013 to the autumn of 2014. The results indicated that the ambient levels and chemical features of PM2.5 exhibited pronounced seasonal variations. Non-sea-salt sulfate (nss-SO42-) constituted the major component of PM2.5, followed by ammonium (NH4+) and nitrate (NO3−) during winter, summer and autumn. However, it was revealed that the mass fraction of NO3− increased to being comparable with nss-SO42- in springtime. The mass contribution of secondary organic carbon (SOC) to PM2.5 peaked in summer (13.2%), inferring the importance of enhanced photo-oxidation reactions in SOC formation. Diurnal variations of O3 and SO2 coincided with each other, suggesting the transport of aged pollutants from distant sources, whereas CO and NOx were shown to be under the influences of both local and regional sources. Notably high sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) were observed, which were 0.93 ± 0.05 and 0.39 ± 0.20, respectively. Precursor gases (i.e. SO2 and NOx) could be converted to sulfate and nitrate during the transport by the uphill winds. Furthermore, due to the high relative humidity at Xitou, enhanced aqueous-phase and/or heterogeneous reactions could further contribute to the formation of sulfate and nitrate at the site. This study demonstrated the significant transport of urban pollutants to a subtropical forest by the mountain-valley circulations as well as the long-range transport from regional sources, whereas the implications of which for regional climate change necessitated further investigation.
Celine Siu Lan Lee; C.C.-K. Chou; Hing Cho Cheung; C.-Y. Tsai; W.-R. Huang; S.-H. Huang; M.-J. Chen; H.-T. Liao; Chang-Fu Wu; T.-M. Tsao; M.-J. Tsai; T.-C. Su. Seasonal variation of chemical characteristics of fine particulate matter at a high-elevation subtropical forest in East Asia. Environmental Pollution 2018, 246, 668 -677.
AMA StyleCeline Siu Lan Lee, C.C.-K. Chou, Hing Cho Cheung, C.-Y. Tsai, W.-R. Huang, S.-H. Huang, M.-J. Chen, H.-T. Liao, Chang-Fu Wu, T.-M. Tsao, M.-J. Tsai, T.-C. Su. Seasonal variation of chemical characteristics of fine particulate matter at a high-elevation subtropical forest in East Asia. Environmental Pollution. 2018; 246 ():668-677.
Chicago/Turabian StyleCeline Siu Lan Lee; C.C.-K. Chou; Hing Cho Cheung; C.-Y. Tsai; W.-R. Huang; S.-H. Huang; M.-J. Chen; H.-T. Liao; Chang-Fu Wu; T.-M. Tsao; M.-J. Tsai; T.-C. Su. 2018. "Seasonal variation of chemical characteristics of fine particulate matter at a high-elevation subtropical forest in East Asia." Environmental Pollution 246, no. : 668-677.
The objective of this study was to investigate associations between cardiovascular effects and urban ambient particle constituents using an in vivo crossover experimental design. Ambient particles were introduced to an exposure chamber for whole-body exposure of WKY rats, where the particulate matter with an aerodynamic diameter of <2.5 μm (PM2.5) mass concentration, particle number concentration, and black carbon (BC) were monitored. Organic carbon (OC), elemental carbon (EC), and soluble ions of PM2.5 were determined. In a crossover design, rats were exposed to ambient particles or high-efficiency particle arrestance (HEPA)-filtered control air for 7 days following a 7-day washout interval. The crossover exposure between particles and HEPA-filtered air was repeated 4 times. Radiotelemetric data on blood pressure (BP) [systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), and mean arterial pressure (MAP)], heart rate (HR), and heart rate viability (HRV) were subsequently obtained during the entire study. Exposure to the PM2.5 mass concentration was associated with decreases in the SBP, DBP, MAP, and HR (p < 0.05), whereas no significant changes in the BP or HR occurred with the particle number or black carbon. For HRV, the ln 5-min standard deviation of the normal-to-normal (NN) interval (LnSDNN) and the ln root mean square of successive differences in adjacent NN intervals (LnRMSSD) were positively associated with the PM2.5 mass concentration (p < 0.05). There were no significant effects of the particle number concentration or BC on HRV. Alterations in the HR were associated with OC, EC, Na+, Cl−, and NO3−. Cl− was associated with the DBP, MAP, HR, SDNN, and RMSSD. NO3− was correlated with the SBP, MAP, HR, SDNN, and RMSSD. In conclusion, we observed cardiovascular responses to ambient particles in vivo using a crossover design which can reduce animal use in future environmental studies.
Hsiao-Chi Chuang; Yin-Jyun Lin; Charles C.K. Chou; Jing-Shiang Hwang; Chu-Chih Chen; Yuan-Horng Yan; Hui-I. Hsieh; Kai-Jen Chuang; Tsun-Jen Cheng. Alterations in cardiovascular function by particulate matter in rats using a crossover design. Environmental Pollution 2017, 231, 812 -820.
AMA StyleHsiao-Chi Chuang, Yin-Jyun Lin, Charles C.K. Chou, Jing-Shiang Hwang, Chu-Chih Chen, Yuan-Horng Yan, Hui-I. Hsieh, Kai-Jen Chuang, Tsun-Jen Cheng. Alterations in cardiovascular function by particulate matter in rats using a crossover design. Environmental Pollution. 2017; 231 ():812-820.
Chicago/Turabian StyleHsiao-Chi Chuang; Yin-Jyun Lin; Charles C.K. Chou; Jing-Shiang Hwang; Chu-Chih Chen; Yuan-Horng Yan; Hui-I. Hsieh; Kai-Jen Chuang; Tsun-Jen Cheng. 2017. "Alterations in cardiovascular function by particulate matter in rats using a crossover design." Environmental Pollution 231, no. : 812-820.
Exposure to air pollutants such as volatile organic compounds (VOCs) and fine particulate matter (PM2.5) are associated with adverse health effects. This study applied multiple time resolution data of hourly VOCs and 24-h PM2.5 to a constrained Positive Matrix Factorization (PMF) model for source apportionment in Taipei, Taiwan. Ninety-two daily PM2.5 samples and 2208 hourly VOC measurements were collected during four seasons in 2014 and 2015. With some a priori information, we used different procedures to constrain retrieved factors toward realistic sources. A total of nine source factors were identified as: natural gas/liquefied petroleum gas (LPG) leakage, solvent use/industrial process, contaminated marine aerosol, secondary aerosol/long-range transport, oil combustion, traffic related, evaporative gasoline emission, gasoline exhaust, and soil dust. Results showed that solvent use/industrial process was the largest contributor (19%) to VOCs while the largest contributor to PM2.5 mass was secondary aerosol/long-range transport (57%). A robust regression analysis showed that secondary aerosol was mostly contributed by regional transport related factor (25%).
Ho-Tang Liao; Yu-Chen Yau; Chun-Sheng Huang; Nathan Chen; Judith C. Chow; John G. Watson; Shih-Wei Tsai; Charles C.-K. Chou; Chang-Fu Wu. Source apportionment of urban air pollutants using constrained receptor models with a priori profile information. Environmental Pollution 2017, 227, 323 -333.
AMA StyleHo-Tang Liao, Yu-Chen Yau, Chun-Sheng Huang, Nathan Chen, Judith C. Chow, John G. Watson, Shih-Wei Tsai, Charles C.-K. Chou, Chang-Fu Wu. Source apportionment of urban air pollutants using constrained receptor models with a priori profile information. Environmental Pollution. 2017; 227 ():323-333.
Chicago/Turabian StyleHo-Tang Liao; Yu-Chen Yau; Chun-Sheng Huang; Nathan Chen; Judith C. Chow; John G. Watson; Shih-Wei Tsai; Charles C.-K. Chou; Chang-Fu Wu. 2017. "Source apportionment of urban air pollutants using constrained receptor models with a priori profile information." Environmental Pollution 227, no. : 323-333.
This study investigated seasonal variations in the mass concentration and chemical composition of ambient aerosols observed at three stations (coastal, mountainous, and downtown sites) in northern Taiwan from March 2009 to February 2012. The results show that the major aerosol components include ammonium, sulfate, nitrate, sea salt, dust, organic carbon, and elemental carbon, whereas the mass fraction of each species depends on the sampling location and season. A significant correlation (r = 0.7–0.8) was observed in aerosol concentrations measured at the respective stations, indicating that aerosol concentrations were dominated by regional‐scale factors. Ammonium, sulfate, and nitrate consistently reached respective peak values in the spring in conjunction with dust particle levels. This shows that the transport of dust and particulate air pollutants from the Asian continent has affected the atmospheric environment in this area. Distinct seasonality was observed for sea salt and secondary organic carbon (SOC): sea salt levels peaked in the autumn, whereas SOC levels peaked in the summer, implying that their sources were regulated by independent seasonal factors. Correlation between sea salt concentration and surface wind speed was derived from coastal measurements and showed a high value for the wind speed sensitivity parameter of around 0.37 for our location. In addition, it was revealed that the SOC concentration in aerosols was positively correlated with oxidant photolysis index (Ox × UVB), suggesting that the SOC seasonality was dominated by hydroxyl radical production.
C. C.‐K. Chou; W.‐C. Hsu; S.‐Y. Chang; W.‐N. Chen; M.‐J. Chen; W.‐R. Huang; Sheng-Hsiu Huang; C.‐Y. Tsai; C.‐T. Lee; S.‐C. Liu. Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia. Journal of Geophysical Research: Atmospheres 2017, 122, 2026 -2042.
AMA StyleC. C.‐K. Chou, W.‐C. Hsu, S.‐Y. Chang, W.‐N. Chen, M.‐J. Chen, W.‐R. Huang, Sheng-Hsiu Huang, C.‐Y. Tsai, C.‐T. Lee, S.‐C. Liu. Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia. Journal of Geophysical Research: Atmospheres. 2017; 122 (3):2026-2042.
Chicago/Turabian StyleC. C.‐K. Chou; W.‐C. Hsu; S.‐Y. Chang; W.‐N. Chen; M.‐J. Chen; W.‐R. Huang; Sheng-Hsiu Huang; C.‐Y. Tsai; C.‐T. Lee; S.‐C. Liu. 2017. "Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia." Journal of Geophysical Research: Atmospheres 122, no. 3: 2026-2042.
Respiratory diseases, particularly allergic rhinitis, are spatially and temporally correlated with the ground PM2.5 level. A study of the correlation between the two factors should therefore account for spatiotemporal variations. Satellite observation has the advantage of wide spatial coverage over pin-point style ground-based in situ monitoring stations. Therefore, the current study used both ground measurement and satellite data sets to investigate the spatial and temporal correlation of satellite-derived PM2.5 with respiratory diseases. This study used 4-year satellite data and PM2.5 levels of the period at eight stations in Taiwan to obtain the spatial and temporal relationship between aerosol optical depth (AOD) and PM2.5. The AOD-PM2.5 model was further examined using the cross-validation (CV) technique and was found to have high reliability compared with similar models. The model was used to obtain satellite-derived PM2.5 levels and to analyze the hospital admissions for allergic rhinitis in 2008. The results suggest that adults (18–65 years) and children (3–18 years) are the most vulnerable groups to the effect of PM2.5 compared with infants and elderly people. This result may be because the two affected age groups spend longer time outdoors. This result may also be attributed to the long-range PM2.5 transport from upper stream locations and the atmospheric circulation patterns, which are significant in spring and fall. The results of the current study suggest that additional environmental factors that might be associated with respiratory diseases should be considered in future studies.
Ching-Ju Liu; Chian-Yi Liu; Ngoc Thi Mong; Charles C. K. Chou. Spatial Correlation of Satellite-Derived PM2.5 with Hospital Admissions for Respiratory Diseases. Remote Sensing 2016, 8, 914 .
AMA StyleChing-Ju Liu, Chian-Yi Liu, Ngoc Thi Mong, Charles C. K. Chou. Spatial Correlation of Satellite-Derived PM2.5 with Hospital Admissions for Respiratory Diseases. Remote Sensing. 2016; 8 (11):914.
Chicago/Turabian StyleChing-Ju Liu; Chian-Yi Liu; Ngoc Thi Mong; Charles C. K. Chou. 2016. "Spatial Correlation of Satellite-Derived PM2.5 with Hospital Admissions for Respiratory Diseases." Remote Sensing 8, no. 11: 914.
The spatio-temporal characteristics of the “holiday effect”, defined as the difference in air pollutant concentrations between the holiday (Chinese New Year) and non-holiday periods during 1994–2008, and its association with the degree of urbanization in Taiwan are examined. Daily surface measurements of six major pollutants from 54 monitoring stations of the Taiwan Environmental Protection Administration are used. Holiday effects are found for almost all air pollutants in all divisions and individual stations. A widespread holiday effect with consistent signs suggests a high degree of urbanization over Taiwan. Holiday effects are stronger in the west than in the east, due to urban-rural differences, and have a distinct north–south difference in the west, due to different emission sources. In the spatial distribution, as the population (motor vehicle) number in the division increases, holiday effects of NOx, CO and NMHC are intensified. Holiday effects of pollutants can also be stronger when the associated dominant anthropogenic sources in the division have larger emissions. Both imply the association of a stronger holiday effect with a higher degree of urbanization in the division. In the temporal variation, on the other hand, holiday effects and pollutant concentrations tend to weaken and reduce in almost all the urban divisions for all six pollutants except O3. These weakening trends imply possible contributions of other effects, such as the mature state of urbanization for the urban division, the effective pollution-control measures and behavioral pattern changes.
Pei-Hua Tan; Chia Chou; Charles C.-K. Chou. Impact of urbanization on the air pollution “holiday effect” in Taiwan. Atmospheric Environment 2013, 70, 361 -375.
AMA StylePei-Hua Tan, Chia Chou, Charles C.-K. Chou. Impact of urbanization on the air pollution “holiday effect” in Taiwan. Atmospheric Environment. 2013; 70 ():361-375.
Chicago/Turabian StylePei-Hua Tan; Chia Chou; Charles C.-K. Chou. 2013. "Impact of urbanization on the air pollution “holiday effect” in Taiwan." Atmospheric Environment 70, no. : 361-375.