Characteristic of ambient air pm2 5 at sub urban area during different periods in taipei

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY DAO THANH HUYEN CHARACTERISTICS OF AMBIENT AIR PM2.5 AT SUBURBAN AREA DURING DIFFERENT PERIODS IN TAIPEI BACHELOR THESIS Study Mode : Full-time Major : Environmental Science and Management Faculty : International Programs Office Batch : 2013 - 2017 Thai Nguyen, September 20, 2017 Thai Nguyen University of Agriculture and Forestry Bachelor of Environmental Science and Degree Program Management Student name DAO THANH HUYEN Student ID DTN 1353130013 Characteristic of ambient air PM2.5 at sub Thesis title urban area during different periods in Taipei Assoc Prof Chi, Kai-Hsien Supervisor(s) Assoc Prof Do Ngoc Oanh Abstract: To identify the characteristic and variation of chemical composition of ambient air PM2.5 during different periods, ambient air PM2.5 samples were collected at suburban area of Taipei city in Taiwan from April 24 to May 1, 2017 PM2.5 samples were taken by a high-volume air sampler The samples was collected in the winter (n=14) and spring (n=8), the concentration, soluble-ion and trace metal were analyzed The PM2.5 concentration in the winter was slightly higher compared to spring which was 18.71 μg/m3 and 16.24 μg/m3, respectively For soluble-ion, the most abundant elements were found to be nss-SO42-, NH4+ and NO3- in both winter and spring which accounting for 88% to over 90% of total soluble-ion mass concentration in both winter and spring In the winter, the most abundant elements were found to be Na accounting for 54.18% and K accounting for 15% of total trace metals mass While in spring, Fe (35.61%) and Ca (25.26%) were the most abundant i Ambient air PM2.5, mass concentration, Key words soluble ions, trace metals, Taipei Number of pages 40 Date of submission 20/09/2017 ii ACKNOWLEDMENT First and foremost, I would like to express my deepest appreciation to my supervisor Associate Professor Chi Kai-Hsien for supportive, guiding, inspired and keep me on the correct path to complete the thesis during the time of conducting the research at Institute of Environmental and Occupational Health Sciences of National Yang Ming University I would like to express my endless thanks and gratefulness to my supervisor Associate Professor Do Ngoc Oanh Her kindly support and continuous advice during my thesis process of completion Her encouragement and comments had significantly enriched and improved my work Without her motivation and instructions, the thesis would have been impossible to be done effectively I wish to express profound gratitude to Mr Lian Jian Guo, Mr Ngô Tuấn Hưng, NaNa, Peggy, Nicole, Joyce and Sherry who are members of Institute of Environmental and Occupational Health Sciences for their kindness, patience guidance, and suggestion and support me to complete my work As last, I would like to thank all members in my big family and my friends, who always believe in me and encourage me unceasingly Thai Nguyen, September 20, 2017 DAO THANH HUYEN iii TABLE OF CONTENTS LIST OF FIGURES vi LIST OF TABLES vii LIST OF ABBREVIATIONS viii PART I INTRODUCTION .1 1.1 Research rationale .1 1.2 Research questions 1.3 Research’s objectives 1.4 Limitation PART II LITERATURE REVIEW .5 2.1 Particulate matter-PM2.5 2.2 Potential sources contribution of PM2.5 2.3 Current PM2.5 sampling methods 2.4 PM2.5 pollution situation in Taipei 10 2.4.1 PM2.5 air quality standard 10 2.4.2 The trend of air quality in Taipei 11 PART III METHODOLOGY .13 3.1 Description of the study area 13 3.2 Samples collection 15 iv 3.3 Chemical analysis .16 PART IV RESULT AND DISCUSSIONS .18 4.1 Ambient air PM2.5 mass concentration at Taipei in winter and spring .18 4.2 Soluble-ion compositions at Taipei in winter and spring .22 4.3 Trace metals composition at Taipei in winter and spring 24 V CONCLUSION 29 REFERENCES 30 APPENDICES 35 v LIST OF FIGURES Figure 2.1: Relative size of particulate matter, a human hair and beach sand (Credit: Environmental Protect Agency) (2007) Figure 3.1: Map of sampling area 14 Figure 4.1: Average mass concentration of PM2.5 in winter and spring compared to the air quality standard The dashed line represents the standard set by the Taiwan EPA 19 Figure 4.2: The proportion of daily samples lower and higher than air quality standard 21 Figure 4.3: Proportion of dominant trace element composition to PM2.5 mass 26 (a) in the winter, (b) in the spring 26 vi LIST OF TABLES Table 2.1: PM2.5 concentration and activities guidance Table 2.2: Major species contribute to ambient air PM2.5 Table 2.3: Global PM2.5 air quality standards (μg/m3) 11 Table 3.1: Methods used for measurements of fine particulate matter PM2.5 16 Table 4.1: Ambient air PM2.5 mass concentrations in winter and spring 18 Table 4.2: The daily mass concentration of PM2.5 and safety level in winter and spring 20 Table 4.3: Mean mass concentration (μg/m3) and proportion contribution of soluble-ions composition in PM2.5 in winter and spring 22 Table 4.4: Mean concentration (ng/m3) and dominant trace metal compositions in PM2.5 in winter and spring 25 vii LIST OF ABBREVIATIONS DAQI Daily Air Quality Index EPA Environmental Protection Agency HC Hydrocarbon NAAQS National Ambient Air Quality Standards OC, EC Organic Carbon, Elementary Carbon PM Particulate Matter PM2.5 Particle mass with diameters less than 2.5 mm PUF Polyurethane Foam TEPA Taiwanese Environmental Protection Administration TRTS Taipei Rapid Transit System U.S EPA United State Environmental Protection Agency WHO World Health Organization viii PART I INTRODUCTION 1.1 Research rationale In recent years, urbanization and modernization are the main causes worsening of air pollution and various sources of particulate matter (PM) World Health Organization (WHO) (WHO, 2016) published a report that ambient air pollution was caused three million deaths globally in 2012 Particulate matter is a complex mixture of solid particles and liquid droplets in the air, it is known as an important part of air pollution Previous studies pointed out that fine particulate matter (PM2.5) which smaller than 10 µm (PM10) in diameter can easily be inhaled by human and accumulate in alveoles but hard to expel (K H Cheng et al., 2013) Fine particulate matters are more toxic than the coarse one When those particles enter the human body through the respiratory system, they can cause a series of acute illnesses or serious respiratory (Nwafor et al., 2007) PM2.5 include organic compounds, metals, combustion particles and chemical component which many of them have been cited as contributors to toxicity and adversely affect human health (Kelly & Fussell, 2012; Pui et al., 2014) According to U.S Environmental Protection Agency (EPA), the long term exposure to PM2.5 may lead to increase the risk of premature death especially in children, elderly and individuals with cardiovascular problems such as heart attacks, irregular heartbeat In addition, for individuals with asthma or suffering from other respiratory diseases, the exposure to PM2.5 may lead to aggravated disease and decreased lung function Such the studies reviewed that PM2.5 increase for every 10 100% 90% 21.43 % 80% 70% 60% 50% 40% 100 % 78.57 % 30% 20% 10% 0% Winter Spring Lower Higher Figure 4.2: The proportion of daily samples lower and higher than air quality standard Table 4.2 shows the daily mass concentration of PM2.5 and Figure 4.2 shows the proportion of daily samples lower and higher than air quality standard Most of the daily mass concentrations of PM2.5 were lower than air quality standard for the entire sampling period in both winter and spring However, there was a significant difference of daily mass concentration among sampling days In winter, there were 11 over the total of 14 samples had lower PM2.5 concentration than air quality standard issued by TEPA, which accounted for 78.57% of total samples In October 29th, November 7th and November 8th, air quality was considered unhealthy for people who with lung and heart problem In spring, the PM2.5 concentration from daily samples was in acceptable range and lower than air quality standard issued by TEPA, which accounted for 100% of samples; people can join their usual outdoor activities 21 Generally, the result found that in spring the PM2.5 level at suburban in Taipei city was in an acceptable to human health However, the air quality in the winter still needs to be improved to reach safety level for every people 4.2 Soluble-ion compositions at Taipei in winter and spring Chemical compositions of soluble-ion in PM2.5 demonstrate an important for air quality assessment According to the previous study, the major soluble-ion components of suburban ambient PM2.5 have been reported as sulfate, nitrate, and ammonium (Hopke et al., 2008) Thus determine soluble-ion compositions are essential to understanding their properties and environmental effects The components of soluble-ion comprised of nss-SO42-, NH4+, NO3-, Na+, K+, Ca2+ and Cl- were found in fine particulate matter PM2.5 with an amount sufficient to effect the variation of air quality Table 4.3 shows the mass concentrations and proportion contribution of the soluble-ion composition in PM2.5 The major solubleion compositions in PM2.5 were nss-SO42-, NH4+ and NO3- which accounted for 88% to over 90% of total soluble-ions mass concentration in both winter and spring Table 4.3: Mean mass concentration (μg/m3) and proportion contribution of solubleions composition in PM2.5 in winter and spring Winter Species nss-SO42NH4+ NO3Na+ K+ Ca2+ ClOthers Mean (μg/m3) 5.164 2.256 1.242 0.226 0.16 0.126 0.089 0.111 Spring % of PM2.5 Mean % of PM2.5 55.08% 24.07% 13.25% 2.41% 1.71% 1.34% 0.96% 1.18% 4.601 1.667 1.179 0.203 0.162 0.217 0.089 0.25 54.77% 19.84% 14.04% 2.42% 1.93% 2.59% 1.06% 3.35% 22 The concentration of nss-SO42- was accounted for more than 50% and followed by NH4+ and NO3- in both winter and spring Nss-SO42- is an important pollutant which attributed to chemical reactions resulting in gas-to particle conversion, mostly in the form of (NH4)2SO4 and NH4HSO4 (Y.-C Hsu et al., 2008) Nss-SO42- mostly originated from local emission sources such as industrial emissions, coal combustion, diesel combustion in Taipei (Lung et al., 2004) Burning activities (i.e coal combustion) could the main reason lead to nss-SO42- in winter (55.08%) was higher than spring (54.77%) The proportion of NH4+ in the winter (24.07%) was much higher than those in spring (19.84%) This is likely due to the agriculture activities and large impact from biomass burning there Agriculture activities is an important source of NH4+ (IPCC, 2007) and attributed to chemical reactions resulting in gas-to particle conversion which mostly produced by reactions between gaseous NH3 and acidic sulfate particles during smoldering combustion (Wang et al., 2006) NO3- concentration is also an important pollutant composition which accounted for 13.25% in the winter and 14.04% in spring The concentration of NO3- was mainly derived from local pollutants such as agricultural activities, vehicular and road dust emission (Liang et al., 2015) According to Choi et al (2012), the concentration of NO3- depends on temperature and humidity The low temperature and the high humidity in spring-the rainy season would impulse the chemical reaction between HNO3 and NH3 vapor resulting the gas phase of nitric acid to the particle phase of nitrate, lead to higher concentration of NO3- Na+ and Cl- were found to be higher in spring These ions are mainly 23 composition of seawater and pass over the ocean and through the dust go to Taipei The percentage of K+, Ca2+ were found to be higher in spring may due to the higher wind speed; which result resuspension of dust from long-range transport pollutants (Ye, 2002) This work also supports for the result of the study that NO3-, NH4+ and nssSO42- were the major components contributed to soluble-ion and mostly from local pollutant sources (Hopke et al., 2008) The PM2.5 concentrations are affected by climatic conditions and Taiwan is often influenced northeasterly winter monsoon winds originating in central Asia in winter and spring The winter monsoon can bring air pollutant and dust over a long distance to northern Taiwan (Lin et al., 2004) The conditions of stagnant and the sunny are typical prior to the frontal passage in Taiwan and local emissions are the main source of air pollutant under these conditions (Lin et al., 2004) 4.3 Trace metals composition at Taipei in winter and spring Trace metals composition emitted into the atmosphere from natural and anthropogenic sources can cause health-related and environmental problems, depending on the extent and time of exposure The high concentration of crustal elements in trace metals composition also shows the importance of wind-blow and dust in air quality Therefore, the trace metals composition and its levels have to be constantly examined to diagnosis status and trend of environmental pollution to take preventive and mitigation measures Table 4.4 shows the dominant chemical compositions of trace metal and mean concentration analyzed in ambient air PM2.5 24 Table 4.4: Mean concentration (ng/m3) and dominant trace metal compositions in PM2.5 in winter and spring Winter Spring Species No (ng/m ) Mean Std Deviation Mean Std Deviation Al 43.75 77.63 47.29 92.68 Fe 61.62 53.25 348.72 110.78 Na 563.29 223.89 6.68 14.95 Mg 36.94 17.75 60.34 42.79 Ca 35.91 44.85 247.40 94.77 K 145.30 133.76 188.10 104.95 Mn 4.46 4.72 7.23 3.79 Zn 33.50 31.16 20.21 14.86 Pb 10.72 10.87 8.67 5.43 There were 46 elements determined for samples collected in this study (Detail in Appendix 3, Table 1.1) In winter, Na, K (100-600 ng/m3) was the dominant metal elements, Al, Fe, Mg, Ca, Zn, Pb (10-70 ng/m3) were also major metals in PM2.5 Ba, Ti, Ni, Cu, Mn in moderate abundance in concentrations (1-10 ng/m3) while the other elements almost invisible to see In spring, Fe, Ca and K were the greatest metal elements (100-400 ng/m3); Al, Mg, Ti and Zn in moderate abundance in concentrations (~10-60 ng/m3) Na, Mn, Pb, and V were in low abundance in concentrations (5-10 ng/m3) while the other elements almost invisible to see However, the elements including Al, Fe, Na, Mg, Ca, K, Zn, Mn, Pb were significant to affect the air quality and also served as markers for analysis source apportionment The other elements considered as enrichment trace metal elements It clearly to see from the table, the concentration of elements including Fe, Mg, Ca, K and Mn in the spring was much higher than those in the winter The concentration of element derived from sea salt (i.e Na) in the winter was superior compared to spring 25 The table shows the large variation in concentration of trace metal concentration in PM2.5 between winter and spring The Al concentration was 43.75 ng/m3 in the winter and 47.29 ng/m3 in the spring The concentration of Zn was 33.5 ng/m3 in the winter and 20.21 ng/m3 in the spring The Pb concentration was 10.72 ng/m3 in the winter period and 8.67 ng/m3 in the spring period The local pollutant sources such as road dust and heating demand in the winter can explain for the higher concentration of Pb and Zn compared to those in spring (a) winter Zn 3.46% Mn Pb 0.46% Other 3.45% 1.11% Ca 3.71% Zn 2.06% Fe 6.36% K 15.00% Na 58.14% Mg 3.81% (b) spring Al 4.52% Mn Other Al 0.74% Pb 4.57% 4.83% 0.89% K 19.21% Fe 35.61% Ca 25.26% Na Mg 0.68% 6.16% Figure 4.3: Proportion of dominant trace element composition to PM2.5 mass (a) in the winter, (b) in the spring 26 Figure 4.3 shows the proportion of abundant concentrations of trace metals found in ambient air PM2.5 This finding illustrated that Na derived from sea salt were the predominant elements which accounted for 58.14% in the winter, while in spring Na only accounted for a negligible amount (0.68%) It was suggested that the concentration of sea salt-derived elements were due to the local production of seawater along the coast, which was driven by surface winds and effect of precipitation (S.-C Hsu et al., 2004) Therefore, it can be explained that the very low Na concentration in spring is due to the influence of precipitation In spring, Fe (35.61%) and Ca (25.26%) were the highest concentration of the total mass of trace metal Meanwhile, in the winter, the concentration of Fe just was 6.36% and Ca was 3.71% These figures were much higher in the spring suggested that the impact of long-range transport of particles generated in frequent Asian dust storm from China as well as by locally generated dust had strongly impacted on Taipei in spring (Liang et al., 2015) The element originate from road dust (i.e: K) was higher in the spring The concentration of K accounted for 19.21% in spring and 15% in the winter It could be due to the effects of strong winds in spring lead to resuspension of the road dust which causes the high concentration of K In spring, the concentration of Al was accounted for 4.83% and Mg accounted for 6.16% of total trace metals mass while Al and Mg in the winter were 4.52% and 3.81%, respectively Al and Mg generated from industrial activities and dust from long range transport (Liu et al., 2002; Zhang et al., 2001) Frequent dust storm in spring could explain for the Al and Mg in spring higher than those in the winter 27 In general, there are significant differences of mass concentration in trace metal compositions in seasonal, industrial activities, the intensity of human activities and frequency of rainfall 28 V CONCLUSION The characteristics of ambient air PM2.5 was presented through the PM2.5 concentration, soluble-ion and trace metal The PM2.5 concentration in the winter was higher than those in spring The PM2.5 concentration was a little different between the two periods which were 18.71 μg/m3 in the winter and 16.24 μg/m3 in the spring The PM2.5 level in spring was in acceptable to human health while in the winter need to be improved The chemical compositions showed that NH4+, NO3- and nss-SO42- were the greatest ions contributed to soluble-ion mass concentrations in both winter and spring nss-SO42- and NH4+ in the winter were higher than those in the spring could due to heating demand in the winter Other soluble-ions include NO3- and Na+, Ca2+, K+ and Cl- were higher in spring could due to nature affects including weather effect and dust storm from China For trace metal elements, in the winter, Na and K were the most abundant elements contribute to trace metal in PM2.5, while in spring; Fe and Ca were the most abundant elements contribute to trace metals composition in PM2.5 Generally, the difference of mass concentration in trace metal compositions is due to the weather effects, the frequency of rainfall, industrial activities, and intensity of human activities In conclude, The chemical composition has significant variation in proportion contribution between the winter and spring The different properties between two periods are the main cause of variation in contribution proportion of those chemical compositions 29 REFERENCES Amaral, S S., de Carvalho, J A., Costa, M A M., & Pinheiro, C (2015) An overview of particulate matter measurement instruments Atmosphere, 6(9), 1327–1345 Anenberg, S C., Belova, A., Brandt, J., Fann, N., Greco, S., Guttikunda, S., … Van Dingenen, R (2015) Survey of Ambient Air Pollution Health Risk Assessment Tools Risk Analysis https://doi.org/10.1111/risa.12540 Bhawan, P., & Nagar, E A (2011) Guidelines for Manual Sampling & Analyses Boyd, D R (2006) The Air We Breathe: An International Comparison of Air Quality Standards and Guidelines David Suzuki Foundation Chan, C.-C., Nien, C.-K., & Hwang, J.-S (1996) Receptor modeling of VOCs, CO, NO x, and THC in Taipei Atmospheric Environment, 30(1), 25–33 Chang, S.-C., & Lee, C.-T (2007) Evaluation of the trend of air quality in Taipei, Taiwan from 1994 to 2003 Environmental Monitoring and Assessment, 127(1), 87–96 Chen, S.-C., Tsai, C.-J., Huang, C.-Y., Chen, H.-D., Chen, S.-J., Lin, C.-C., … Huang, W.-R (2010) Chemical mass closure and chemical characteristics of ambient ultrafine particles and other PM fractions Aerosol Science and Technology, 44(9), 713–723 Cheng, K H., EiF, M L., EiC, M H., & ImJ, J L (2013) Characteristics of the Spatial and Temporal Variations of Ambient PM2.5 Concentration at Kaohsiung City Applied Mechanics and Materials https://doi.org/10.4028/www.scientific.net/AMM.333335.1724 LB - 2674929 Cheng, Y., He, K., Du, Z., Zheng, M., Duan, F., & Ma, Y (2015) Humidity plays an important role in the PM 2.5 pollution in Beijing Environmental Pollution, 197, 68–75 30 Choi, J.-K., Heo, J.-B., Ban, S.-J., Yi, S.-M., & Zoh, K.-D (2012) Chemical characteristics of PM 2.5 aerosol in Incheon, Korea Atmospheric Environment, 60, 583–592 Chow, J C., & Watson, J G (1998) Guideline on speciated particulate monitoring Report Prepared for US Environmental Protection Agency, Research Triangle Park, NC, by Desert Research Institute, Reno, NV Claiborn, C S., Finn, D., Larson, T V, & Koenig, J Q (2000) Windblown dust contributes to high PM25 concentrations Journal of the Air & Waste Management Association, 50(8), 1440–1445 Dockery, D W., Pope, C A., Xu, X., Spengler, J D., Ware, J H., Fay, M E., … Speizer, F E (1993) An association between air pollution and mortality in six US cities New England Journal of Medicine, 329(24), 1753–1759 Englert, N (2004) Fine particles and human health—A review of epidemiological studies Toxicol Lett, (149), 235–242 Haddad, F (1998) A thesis submitted to the faculty of graduate studies in partial fulfilment of the requirements for the degree of master of science University Of Calgary Hopke, P K., Kothai, P., Saradhi, I V, Prathibha, P., Pandit, G G., & Puranik, V D (2008) Source apportionment of coarse and fine particulate matter at Navi Mumbai, India Aerosol and Air Quality Research, 8(4), 423–436 Hsu, S.-C., Liu, S C., Lin, C.-Y., & Hsu, R.-T (2004) Metal Compositions of PM 10 and PM Aerosols in Taipei during Spring , 2002, 15(5), 925–948 Hsu, Y.-C., Lai, M.-H., Wang, W.-C., Chiang, H.-L., & Shieh, Z.-X (2008) Characteristics of Water-Soluble Ionic Species in Fine (PM2 5) and Coarse Particulate Matter (PM10– 2.5) in Kaohsiung, Southern Taiwan Journal of the Air & Waste Management 31 Association, 58(12), 1579–1589 Hu, G., Zhang, Y., Sun, J., Zhang, L., Shen, X., Lin, W., & Yang, Y (2014) Variability, formation and acidity of water-soluble ions in PM 2.5 in Beijing based on the semicontinuous observations Atmospheric Research, 145, 1–11 Hu, J., Zhang, H., Chen, S., Ying, Q., Wiedinmyer, C., Vandenberghe, F., & Kleeman, M J (2014) Identifying PM2 and PM0 sources for epidemiological studies in California Environmental Science & Technology, 48(9), 4980–4990 IPCC (2007) Fourth assessment report IPCC, Ge Janhäll, S (2015) Review on urban vegetation and particle air pollution–Deposition and dispersion Atmospheric Environment, 105, 130–137 Kelly, F J., & Fussell, J C (2012) Size, source and chemical composition as determinants of toxicity attributable to ambient particulate matter Atmospheric Environment, 60, 504– 526 Liang, C.-S., Yu, T.-Y., & Lin, W.-Y (2015) Source apportionment of submicron particle size distribution and PM2 composition during an Asian dust storm period in two urban atmospheres Aerosol Air Qual Res, 15, 2609–2624 Lin, C.-Y., Liu, S C., Chou, C C K., Liu, T H., Lee, C.-T., Yuan, C.-S., … Young, C.-Y (2004) Long-range transport of Asian dust and air pollutants to Taiwan Terrestrial, Atmospheric and Oceanic Sciences, 15(5), 759–784 Liu, C L., Zhang, J., & Shen, Z B (2002) Spatial and temporal variability of trace metals in aerosol from the desert region of China and the Yellow Sea Journal of Geophysical Research: Atmospheres, 107(D14) 32 Lizong, L (1985) Synoptic and climatic characteristics of the surface inversion in Nanjing region Scientia Meteorologica Sinica, 2, Lung, S.-C C., Liu, C.-H., Huang, S.-Y., Lin, T.-J., Chou, C C K., & Liu, S C (2004) Water-soluble ions of aerosols in Taipei in spring 2002 Terrestrial, Atmospheric and Oceanic Sciences, 15(5), 901–923 Nel A., Xia T., Madler L., and L N (2006) Toxic potential of materials at the nanolevel Science, 5761(311), 622–627 NIEA (1992) 空氣粒狀污染物中硫酸鹽、氯鹽、硝酸鹽檢測方法－離子層析法 Nwafor, K., O., Chineke, C., T., Pinker, & T., R (2007) Seasonal Characteristics of Aerosol Research, Optical Properties at a Sub-Sahara Site Atmospheric Research, (85), 38–51 Pope III, C A., Thun, M J., Namboodiri, M M., Dockery, D W., Evans, J S., Speizer, F E., & Heath Jr, C W (1995) Particulate air pollution as a predictor of mortality in a prospective study of US adults American Journal of Respiratory and Critical Care Medicine, 151(3_pt_1), 669–674 Pui, D Y H., Chen, S.-C., & Zuo, Z (2014) PM 2.5 in China: Measurements, sources, visibility and health effects, and mitigation Particuology, 13, 1–26 Rohde, R A., & Muller, R A (2015) Air pollution in China: Mapping of concentrations and sources PloS One, 10(8), e0135749 U.S Environmental Protection Agency (2009) Integrated Science Assessment for Particulate Matter (Final Report) United States Environmental Protection Agency Wang, Y., Zhuang, G., Zhang, X., Huang, K., Xu, C., Tang, A., … An, Z (2006) The ion chemistry, seasonal cycle, and sources of PM 2.5 and TSP aerosol in Shanghai 33 Atmospheric Environment, 40(16), 2935–2952 WHO (2016) Ambient air pollution: a global assessment of exposure and burden of disease In Ambient air pollution: a global assessment of exposure and burden of disease Ye, J R (2002) The influence of Asian dust storms on acidic air pollutants in Central Taiwan Master Thesis National Chung-Hsing University., Taichung, Taiwan Yu, H.-L., Wang, C.-H., Liu, M.-C., & Kuo, Y.-M (2011) Estimation of fine particulate matter in Taipei using landuse regression and Bayesian maximum entropy methods International Journal of Environmental Research and Public Health, 8(6), 2153–2169 Zhang, J., Wu, Y., Liu, C L., Shen, Z B., Yu, Z G., & Zhang, Y (2001) Aerosol characters from the desert region of Northwest China and the Yellow Sea in spring and summer: observations at Minqin, Qingdao, and Qianliyan in 1995–1996 Atmospheric Environment, 35(29), 5007–5018 34 APPENDICES APPENDIX 1: Table 1.1: Trace metals compositions and mean concentration (ng/m3) of PM2.5 in winter and spring Winter Spring Species No (ng/m3) Mean Std Deviation Mean 10 11 12 13 14 15 16 17 18 19 20 21 22 23 43.75 61.62 563.29 36.94 35.91 145.30 0.57 2.16 3.12 4.46 0.10 3.46 3.63 33.50 1.41 0.23 1.22 1.03 0.06 10.72 4.47 1.52 1.31 77.63 53.25 223.89 17.75 44.85 133.76 0.32 2.14 3.39 4.72 0.07 2.57 3.90 31.16 2.67 0.25 1.50 1.09 0.05 10.87 4.71 1.24 1.03 47.29 348.72 6.68 60.34 247.40 188.10 0.81 1.44 19.86 7.23 0.13 2.42 3.59 20.21 0.12 0.14 1.11 1.20 0.09 8.67 6.58 4.04 1.17 Al Fe Na Mg Ca K Sr Ba Ti Mn Co Ni Cu Zn Mo Cd Sn Sb Tl Pb V Cr As Winter Spring Species No Std Std Std (ng/m3) Mean Mean Deviation Deviation Deviation 92.68 110.78 14.95 42.79 94.77 104.95 0.61 2.64 9.66 3.79 0.08 2.00 3.17 14.86 0.00 0.10 1.06 0.97 0.03 5.43 4.32 1.41 0.85 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Y Se Zr Ge Rb Cs Ga La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf U 0.04 0.84 6.08 0.84 0.35 0.02 0.36 0.08 0.07 0.02 0.12 0.00 0.00 0.01 0.04 0.00 0.04 0.00 0.00 0.00 0.01 0.12 0.01 0.06 1.05 1.52 0.30 0.29 0.02 0.25 0.09 0.08 0.01 0.05 0.01 0.00 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00 0.07 0.02 0.00 1.36 0.02 0.00 0.57 0.04 0.04 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.28 0.00 0.00 0.22 0.01 0.08 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 35 ... analyzing the characteristic of fine particulate matter PM2. 5 Table 3.1: Methods used for measurements of fine particulate matter PM2. 5 Measurement of fine particulate matter PM2. 5 PM2. 5 trace... concentration of PM2. 5 and safety level in winter and spring Date of sampling Winter (n=14) Spring (n=8) 28/10/20 15 29/10/20 15 30/10/20 15 31/10/20 15 1/11/20 15 2/11/20 15 3/11/20 15 4/11/20 15 5/11/20 15. .. composition of ambient air PM2. 5 during different periods, ambient air PM2. 5 samples were collected at suburban area of Taipei city in Taiwan from April 24 to May 1, 2017 PM2. 5 samples were taken