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The study of TSP, PM2.5–10 and PM2.5 during Taiwan Chi-Chi Earthquake in the traffic site of central Taiwan, Taichung
Chemosphere 41 (2000) 1727±1731
The study of TSP, PM2:5±10 and PM2:5 during Taiwan Chi-Chi Earthquake in the trac site of central Taiwan, Taichung Guor-Cheng Fang a,*, Cheng-Nan Chang b, Nai-Phon Wang c, Yuh-Shen Wu a, Vicky Wang d, Peter Pi-Cheng Fu e, Chii-Dong Cheng b, Shun-Chin Chen b, Don-Yee Lin a a
Air Toxic and Environmental Analysis Laboratory, Hungkuang Institute of Technology, Sha-Lu, Taichung 433, Taiwan b Department of Environmental Science, Tunghai University, Taichung 407, Taiwan c Department of Health Care Administration, Hungkuang Institute of Technology, Sha-Lu, Taichung 433, Taiwan d Oce of Secretary, Chief Secretary, Hungkuang Institute of Technology, Sha-Lu, Taichung 433, Taiwan e Division of Biochemical Toxicology, National Center for Toxicological Research, Jeerson, Arkansas 72079, USA Received 12 January 2000; accepted 10 February 2000
Abstract Ambient particle concentration was taken on the trac sampling site over the Chung-Chi Road over bridge (CCROB) in front of Hungkuang Institute of Technology (HKIT). The sampling time was from August 1999 to December 1999. During the sampling period, Taiwan's biggest earthquake in more than a century registered 7.3 on the Richter scale (Taiwan Chi-Chi Earthquake). Besides, there were more than 20,000 aftershocks that followed the Taiwan Chi-Chi Earthquake within three months. Thus, the PM2:5 , PM2:5±10 particle concentrations were also collected then and compared with total suspended particle (TSP) in this study. The average PM2:5±10 , PM2:5 and TSP concentrations are 24.6, 58.0 and 106 lg/m3 , respectively, after the Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after Taiwan Chi-Chi Earthquake were 70 and 127 lg/m3 , respectively. It is clearly shown that the average concentration of TSP after Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before Taiwan Chi-Chi Earthquake in the trac site of central Taiwan. And the ratios of PM2:5 /PM2:5±10 , PM2:5 /PM10 and PM2:5 /TSP are 2.2%, 67.2%, 38.9%, respectively. The results also indicated about Chi-Chi ®ne particle concentration (PM2:5 ) and the TSP increases in the trac site of central Taiwan after Taiwan Chi-Chi Earthquake. Ó 2000 Elsevier Science Ltd. All rights reserved. Keywords: PM2:5 ; PM2:5±10 ; TSP; Earthquake; Particulate matter
1. Introduction Ambient aerosol particles cover a size range from a few nanometers up to several tens of micrometers in diameter. Ultra®ne particle with diameters less than 0.1 lm originate mainly from gas-to-particle conversion
*
Corresponding author. Tel.: +886-4-631-8652 ext. 230; fax: +886-4-350-2102. E-mail address: [email protected] (G.-C. Fang).
or combustion processes. These ultra®ne particles coagulate rapidly depending on their concentration and thermodynamic conditions forming larger particles attributed to the accumulation mode which ranges from 0.1 up to 1.0 lm (Tuch et al., 2000). Secondary aerosol, sea spray exhaust from diesel engine combustion, photochemical production, exhaust from power plants, and incomplete combustion exhaust from vehicles are the major air pollution sources in Central Taiwan (Chen et al., 1998). Recent epidemiological studies have shown that suspended particulate matter and lung function
0045-6535/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 0 4 5 - 6 5 3 5 ( 0 0 ) 0 0 0 5 5 - 2
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G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731
parameter, respiratory symptoms and mortality have been found (Dockery et al., 1993). The health-related ®ndings of these studies were associated with either the total mass concentration of suspended particles (TSP) or the mass concentration of particles with aerodynamic diameters smaller than 10 lm (PM10 ) or smaller than 2.5 lm (PM2:5 ) (Tuch et al., 2000). Only few measurements were about the contribution of coarse particles (aerodynamic diameter dae > 10 lm) to the total atmospheric particle concentration. One reason is that coarse particles are dicult to quantitatively sample. Another reason is that many measurements of atmospheric particle concentrations focus on air pollution problems associated with small particles from combustion sources (Wagenpfeil et al., 1999). Standards for monitoring this pollution have been established; however, as technology improves in measurement techniques and more information becomes available on the relationship between exposure and health eects, it has become more apparent that existing standards may need to be revised to include monitoring of a ®ner particle size range (Hitchins et al., 2000). Besides, Hitchins indicates a contribution from suspended road dust, which means that vehicle exhaust emissions may not be the main source for PM10 and PM2:5 in proximity to a busy road. One of the important emission sources in urban areas is fugitive dust, which can arise from a wide variety of sources including paved and unpaved roads, industrial areas, and construction and agricultural activities. Fugitive dust is usually associated with the coarse fraction (>2.5 lm) of atmospheric aerosols (Holsen et al., 1998). 2. Experimental 2.1. Sampling program Ambient particle concentration was taken on the bridge in front of Hungkuang Institute of Technology (HKIT). HKIT is located 500 m high of Da Du Mountain. It is a medium-large school and has around 9000 students. However the bridge is a characteristic of trac sampling site over the Chung-Chi Road over bridge (CCROB) (Fig. 1). The sampling height was about 9 m high and the sampling time was from August 1999 to December 1999. Then, the sampling information is listed in Table 1. During the sampling period, Taiwan's biggest earthquake, which occurred on September 21, 1999 (921 Taiwan Chi-Chi Earthquake) in more than a century registered 7.3 on the Richter scale, leaving more than 2200 people dead, 6500 injured and 100,000 homeless. Besides, there are more than 20,000 aftershocks that followed the Taiwan Chi-Chi Earthquake within three months. And Chi-Chi Town was located at the central part of Taiwan. It was about 50 km on the South-eastern part of CCROB (Fig. 2). Thus, the
Fig. 1. The trac sampling site over CCROB.
Table 1 Sampling information (1999) Date
Sampling time (min)
Sampling device
Before 921 Earthquake 8/16 335 8/19 281 8/26 313 8/27 343 9/09 1473 9/10 1373 9/11 1440 9/12 1440
TSP TSP TSP TSP TSP TSP TSP TSP
After 921 Earthquake 10/03 1440 10/21 1464 10/23 1381 10/29 1128 11/01 1445 11/03 1440 11/04 1440 11/05 1380 11/07 1400 11/16 1380 11/17 1459 11/22 1412 12/04 1576 12/11 1431
TSP TSP TSP TSP TSP, TSP, TSP, TSP, TSP, TSP, TSP, TSP, TSP, TSP,
Universal Universal Universal Universal Universal Universal Universal Universal Universal Universal
Fig. 2. The locations of the sampling site from the epicenter (Chi-Chi Town).
G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731
PM2:5 , PM2:5±10 particle concentrations were also collected then and compared with TSP in this study. TSP samples were concurrently collected on Glass Micro®ber ®lters by PS-1 samplers. Daily dichotomous sampler (<2.5 and 2.5±10 lm) were collected on Glass Micro®ber ®lters with the universal dichotomous sampler. 2.2. PS-1 sampler The PS-1 (Gps1 Poly-Urethane Filter (PUF) sampler, General Metal Work) consists of nine basic assemblies: Dual chamber, sampling module, ¯ow vent, magnehelic gage, voltage variator, elapsed time indicator, pump, 7-day skip timer, exhaust hose and aluminum shelter. The PS-1 is a completed air sampling system designed to simultaneously collect suspended airborne particles at ¯ow rate up to 280 l/min and the ¯ow rate was adjusted to 200 l/min in this study. The Glass Micro®ber ®lters (diameter 10.2 lm) are used to ®lter the suspended particle in this study. The ®lter paper is put into the dry box for at least 48 h until the humidity equilibrium. Before sampling, the ®lter paper is got from the dry box and is weighted the initial mass. And the ®lter paper is placed onto the dustfree box. Then the ®lter is brought to the sampling site. After sampling, the ®lter is also put into the dust-free box for at least 48 h until the humidity equilibrium and then weighted the ®nal mass. 2.3. Universal sampler The Model 310 Universal Air SamplerTM (USATM ) is a general purpose air sampler for atmospheric aerosol sampling and for mass concentration, and organic or inorganic analysis. The sampler has a design inlet sampling ¯ow rate of 300 l/min. Fully equipped, it includes two virtual impactors for size fractionation of airborne
1729
particles and a PUF sampler for analysis of volatile organic compounds (VOCs) in the air sample. The sampler is provided with an omni-directional inlet, a PM10 (10 lm cut) virtual impactor classi®er, either a PM2:5 or PM10 virtual impactor classi®er, a ®ne particle ®lter and a PUF sampler. This allows operation as a high volume dichotomous sampler for size fractionation of airborne particle in the 0±2.5 lm and 2.5±10 lm aerodynamic size ranges. Air is sampled at 300 l/min from the ambient atmosphere through an omni-directional, cylindrical inlet. Particles greater than 10 lm aerodynamic equivalent diameter are removed from the sampled air stream by the PM10 classi®er and discarded. Particle less than 10 lm ¯ow to the PM2:5 classi®er located downstream. Particles in the 2.5±10 lm range are collected on a 62 165 mm2 ®lter and those smaller than 2.5 mm are collected on a 200 250 mm2 ®nal ®lter. The ®ltered air stream is then directed through the PUF sampler to collect the VOCs in the ®ltered air stream (Universal Air Sampler, 1996).
3. Results and discussion 3.1. The ambient air particle concentrations in the trac site (CCROB) In Fig. 3, it displayed the concentration variation of TSP before and after 921 Taiwan Chi-Chi Earthquake. It was found that the concentration of TSP increases after 921 Taiwan Chi-Chi Earthquake signi®cantly. It also showed the concentration variation of PM10 and TSP at CCROB sampling site after 921 Taiwan Chi-Chi Earthquake. Basically, PM10 and TSP have the same distribution trend. And the average concentration ratio for TSP/PM10 after 921 Taiwan Chi-Chi Earthquake is about 1.5.
Fig. 3. The concentration variation of TSP and PM10 during 921 Taiwan Chi-Chi Town.
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G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731
The ambient air particle concentrations of PM2:5±10 , PM2:5 and TSP are displayed in Table 2. These results indicated that the average PM2:5±10 , PM2:5 and TSP concentrations are 24.6, 58.0 and 106 lg/m3 , respectively. Apparently, the concentration of PM2:5±10 is lower than PM2:5 . It is due to the exhaust of vehicles, and these vehicle emissions were mainly composed of ®ne particles (PM2:5 ) (Fang et al., 1999). The average TSP concentrations before and after 921 Taiwan Chi-Chi Earthquake were 70 and 127 lg/m3 , respectively. It is clearly shown that the average concentration of TSP after 921 Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before 921 Taiwan Chi-Chi Earthquake. 3.2. The ratios of TSP, PM2:5±10 and PM2:5 in the trac sampling site (CCROB) The ratios of TSP, PM2:5±10 and PM2:5 in the trac sampling site (CCROB) after 921 Taiwan Chi-Chi Earthquake were displayed in Table 3. First, the ratios Table 2 TSP, PM2:5±10 and PM2:5 particle concentration in the trac site (CCROB, 1999) Date
Concentration (lg/m3 ) PM2:5±10
Before 921 Earthquake 8/16 ± 8/19 ± 8/26 ± 8/27 ± 9/09 ± 9/10 ± 9/11 ± 9/12 ±
PM2:5 ± ± ± ± ± ± ± ±
Average
60.7 84.1 58.2 43.2 73.8 66.5 96.7 73.3 70
After 921 Earthquake 10/03 ± 10/21 ± 10/23 ± 10/29 ± 11/01 20.6 11/03 16.2 11/04 32.5 11/05 37.2 11/07 19.3 11/16 23.8 11/17 18.3 11/22 24.7 12/04 32.5 12/11 20.6
± ± ± ± 25.4 25.3 92.6 116 29.2 40.7 28.4 61.4 97.3 64.7
Average Total average
TSP
66.3 116 96.8 122 102 84.9 196 232 102 121 115 113 188 123 127
24.6
58.0
106
Table 3 The ratios of TSP, PM2:5±10 and PM2:5 in the trac site after 921 Taiwan Chi-Chi Earthquake (CCROB, 1999) Date
PM2:5 / PM2:5±10
PM2:5 /PM10 (%)
PM2:5 /TSP (%)
11/1 11/3 11/4 11/5 11/7 11/16 11/17 11/22 12/04 12/11
1.2 1.6 2.8 3.1 1.5 1.7 1.6 2.5 3 3.1
55.3 61 74 75.6 60.2 63.1 60.8 71.3 75 75.9
24.8 29.9 47.3 49.8 28.7 33.5 24.6 46 51.8 52.6
Average
2.2
67.2
38.9
of PM2:5 /PM2:5±10 were ranged from 1.2 to 3.1 and were averaged 2.2. These results indicated that the average ®ne particles concentrations were about 2.2 times as that of coarse particles concentration in the trac sampling site (CCROB) after 921 Taiwan Chi-Chi Earthquake. Besides, the average ratios of PM2:5 /PM2:5±10 were higher than previous studies (Fang et al., 1999); increase about 120% which indicated ®ne particle concentration increase compared to the coarse particles concentration at the trac sampling site after 921 Taiwan Chi-Chi Earthquake. Second, the ratios of PM2:5 /PM10 were ranged from 55.3% to 75.9% and were averaged 67.2%. These results were dierent from previous study whose data were collected by day and night time, respectively. And the average ratio of PM2:5 /PM10 in this study increases about 17% compared to that of the previous study (Fang et al., 1999) during the 921 Taiwan Chi-Chi Earthquake period. Finally, the ratios of PM2:5 /TSP were ranged from 24.6% to 52.6% and were averaged 38.9%. These results in the trac sampling site were much higher than those data collected in the rural sites (Fang et al., 1999). This is because that the exhaust of vehicles, and these vehicle emissions were mainly composed of ®ne particles. However, the average ratio of PM2:5 /TSP in this study decreases about 15% compared to those data in the trac sampling site in the previous study (Chang, 1998). Apparently, the ratio of the particles that were less than 2.5 lm in the PM10 increased and the ratio of the particles that were less than 10 lm in the TSP decreased after the 921 Taiwan Chi-Chi Earthquake. To sum up, the ®ne particle concentration (PM2:5 ) increased in the trac site of central Taiwan after 921 Taiwan Chi-Chi Earthquake. And the total suspended particle (TSP) concentration also increased after 921 Taiwan Chi-Chi Earthquake. The particle concentration for PM2:5±10 and PM2:5 compared to the other studies is displayed in Table 4. It
G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731 Table 4 Particle concentrations compare to other studies Sampling sites
PM2:5 (lg/m3 )
PM2:5±10 (lg/m3 )
Waterrown (Boston) Long Beach (California) GU Site (Brisbane) Kashima (Japan) Quebec (Canada) Montreal (Canada) Taichung (Taiwan) This study (Taiwan)
17.4
17.4
48.6
22.5
7.3
10.4
17.7
17.5
11.9
11.6
20.9
23.7
29.7
25.8
58
24.6
showed that the particle concentration of PM2:5 is signi®cantly higher than those of the other areas while the particle concentration of PM2:5±10 is not dierent from those of the other areas. This is because of the in¯uence of 921 Taiwan Chi-Chi Earthquake. It enhances the ®ne particles concentration (PM2:5 ). 4. Conclusion The main conclusions in this paper are listed as follows: 1. It was found that the concentration of TSP increases signi®cantly after 921 Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after 921 Taiwan Chi-Chi Earthquake were 70 and 127 lg/m3 , respectively. It is clearly shown that the average concentration of TSP after 921 Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before 921 Taiwan Chi-Chi Earthquake. 2. The average ambient air particle concentrations of PM2:5±10 , PM2:5 and TSP were 24.6, 58.0 and 106 lg/m3 , respectively. And the average concentration ratios for TSP/PM10 , TSP/PM2:5 were 1.5, 2.2, respectively after the 921 Taiwan Chi-Chi Earthquake. 3. The average ®ne particles concentration were about 2.2 times as that of coarse particles concentration in the trac sampling site (CCROB) after the 921
1731
Taiwan Chi-Chi Earthquake. Besides, the average ratios of PM2:5 /PM2:5±10 increases about 120% which indicated ®ne particle concentration increase compared to the coarse particles concentration at the trac sampling site after 921 Taiwan Chi-Chi Earthquake. 4. The ®ne particle concentration (PM2:5 ) and the TSP concentration both increase after the 921 Taiwan Chi-Chi Earthquake in the trac site of central Taiwan. Acknowledgements The ®nancial support provided by the Hungkuang Institute of Technology of Humanities and Science Council, through a research contract (HKHSC-90-01) is gratefully appreciated.
References Chang, K.F., 1998. Characteristics study of ambient air particle concentrations at trac and rural area during day and night period in central Taiwan. M.S. Thesis. Chen, C.Y., Cheng, M.T., Zuang, P.C., 1998. The Total Quantity Control in Taichung Pork. EPA, Taiwan, Taichung. Dockery, D.W., Pope, C.A., Xu, X., Spengler, J.D., Ware, J.H., Fay, M.E., Ferris, B.G., Speizer, G.E., 1993. An association between air pollution and mortality in six US cities. NEW Engl. J. Med. 329, 1753±1759. Fang, G.C., Wu, Y.S., Chang, C.N., Chang, K.F., Yang, D.G., 1999. Modeling dry deposition of total particle mass in tracked and rural sites of central Taiwan. Environ. Internat. 25 (5), 625±633. Hitchins, J., Morawska, L., Wol, R., Gilbert, D., 2000. Concentrations of submicrometer particles from vechicle emissions near a major road. Atmos. Environ. 34, 51±59. Tuch, Th., Mirme, A., Tamm, E., Heinrich, J., Hyder, J., Brand, P., Roth, Ch., Wichmann, H.E., Pekkanen, J., Kreuling, W.G., 2000. Comparison of two particle-size spectrometers for ambient aerosol measurements. Atmos. Environ. 34, 139±149. Universal Air Sampler, 1996. Model 310 Universal Air SamplerTM Instruction Manual (USATM ), MSP Corporation, I313 Fifth Street, S.E. Suite 206 Minneapolis, MN55414, USA. Wagenpfeil, F., Paretzke, H.G., Peres, J.M., Tschiersch, J., 1999. Resuspension of coarse particles in the region of chernobyl. Atmos. Environ. 33, 3313±3323.
The study of TSP, PM2:5±10 and PM2:5 during Taiwan Chi-Chi Earthquake in the trac site of central Taiwan, Taichung Guor-Cheng Fang a,*, Cheng-Nan Chang b, Nai-Phon Wang c, Yuh-Shen Wu a, Vicky Wang d, Peter Pi-Cheng Fu e, Chii-Dong Cheng b, Shun-Chin Chen b, Don-Yee Lin a a
Air Toxic and Environmental Analysis Laboratory, Hungkuang Institute of Technology, Sha-Lu, Taichung 433, Taiwan b Department of Environmental Science, Tunghai University, Taichung 407, Taiwan c Department of Health Care Administration, Hungkuang Institute of Technology, Sha-Lu, Taichung 433, Taiwan d Oce of Secretary, Chief Secretary, Hungkuang Institute of Technology, Sha-Lu, Taichung 433, Taiwan e Division of Biochemical Toxicology, National Center for Toxicological Research, Jeerson, Arkansas 72079, USA Received 12 January 2000; accepted 10 February 2000
Abstract Ambient particle concentration was taken on the trac sampling site over the Chung-Chi Road over bridge (CCROB) in front of Hungkuang Institute of Technology (HKIT). The sampling time was from August 1999 to December 1999. During the sampling period, Taiwan's biggest earthquake in more than a century registered 7.3 on the Richter scale (Taiwan Chi-Chi Earthquake). Besides, there were more than 20,000 aftershocks that followed the Taiwan Chi-Chi Earthquake within three months. Thus, the PM2:5 , PM2:5±10 particle concentrations were also collected then and compared with total suspended particle (TSP) in this study. The average PM2:5±10 , PM2:5 and TSP concentrations are 24.6, 58.0 and 106 lg/m3 , respectively, after the Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after Taiwan Chi-Chi Earthquake were 70 and 127 lg/m3 , respectively. It is clearly shown that the average concentration of TSP after Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before Taiwan Chi-Chi Earthquake in the trac site of central Taiwan. And the ratios of PM2:5 /PM2:5±10 , PM2:5 /PM10 and PM2:5 /TSP are 2.2%, 67.2%, 38.9%, respectively. The results also indicated about Chi-Chi ®ne particle concentration (PM2:5 ) and the TSP increases in the trac site of central Taiwan after Taiwan Chi-Chi Earthquake. Ó 2000 Elsevier Science Ltd. All rights reserved. Keywords: PM2:5 ; PM2:5±10 ; TSP; Earthquake; Particulate matter
1. Introduction Ambient aerosol particles cover a size range from a few nanometers up to several tens of micrometers in diameter. Ultra®ne particle with diameters less than 0.1 lm originate mainly from gas-to-particle conversion
*
Corresponding author. Tel.: +886-4-631-8652 ext. 230; fax: +886-4-350-2102. E-mail address: [email protected] (G.-C. Fang).
or combustion processes. These ultra®ne particles coagulate rapidly depending on their concentration and thermodynamic conditions forming larger particles attributed to the accumulation mode which ranges from 0.1 up to 1.0 lm (Tuch et al., 2000). Secondary aerosol, sea spray exhaust from diesel engine combustion, photochemical production, exhaust from power plants, and incomplete combustion exhaust from vehicles are the major air pollution sources in Central Taiwan (Chen et al., 1998). Recent epidemiological studies have shown that suspended particulate matter and lung function
0045-6535/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 0 4 5 - 6 5 3 5 ( 0 0 ) 0 0 0 5 5 - 2
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G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731
parameter, respiratory symptoms and mortality have been found (Dockery et al., 1993). The health-related ®ndings of these studies were associated with either the total mass concentration of suspended particles (TSP) or the mass concentration of particles with aerodynamic diameters smaller than 10 lm (PM10 ) or smaller than 2.5 lm (PM2:5 ) (Tuch et al., 2000). Only few measurements were about the contribution of coarse particles (aerodynamic diameter dae > 10 lm) to the total atmospheric particle concentration. One reason is that coarse particles are dicult to quantitatively sample. Another reason is that many measurements of atmospheric particle concentrations focus on air pollution problems associated with small particles from combustion sources (Wagenpfeil et al., 1999). Standards for monitoring this pollution have been established; however, as technology improves in measurement techniques and more information becomes available on the relationship between exposure and health eects, it has become more apparent that existing standards may need to be revised to include monitoring of a ®ner particle size range (Hitchins et al., 2000). Besides, Hitchins indicates a contribution from suspended road dust, which means that vehicle exhaust emissions may not be the main source for PM10 and PM2:5 in proximity to a busy road. One of the important emission sources in urban areas is fugitive dust, which can arise from a wide variety of sources including paved and unpaved roads, industrial areas, and construction and agricultural activities. Fugitive dust is usually associated with the coarse fraction (>2.5 lm) of atmospheric aerosols (Holsen et al., 1998). 2. Experimental 2.1. Sampling program Ambient particle concentration was taken on the bridge in front of Hungkuang Institute of Technology (HKIT). HKIT is located 500 m high of Da Du Mountain. It is a medium-large school and has around 9000 students. However the bridge is a characteristic of trac sampling site over the Chung-Chi Road over bridge (CCROB) (Fig. 1). The sampling height was about 9 m high and the sampling time was from August 1999 to December 1999. Then, the sampling information is listed in Table 1. During the sampling period, Taiwan's biggest earthquake, which occurred on September 21, 1999 (921 Taiwan Chi-Chi Earthquake) in more than a century registered 7.3 on the Richter scale, leaving more than 2200 people dead, 6500 injured and 100,000 homeless. Besides, there are more than 20,000 aftershocks that followed the Taiwan Chi-Chi Earthquake within three months. And Chi-Chi Town was located at the central part of Taiwan. It was about 50 km on the South-eastern part of CCROB (Fig. 2). Thus, the
Fig. 1. The trac sampling site over CCROB.
Table 1 Sampling information (1999) Date
Sampling time (min)
Sampling device
Before 921 Earthquake 8/16 335 8/19 281 8/26 313 8/27 343 9/09 1473 9/10 1373 9/11 1440 9/12 1440
TSP TSP TSP TSP TSP TSP TSP TSP
After 921 Earthquake 10/03 1440 10/21 1464 10/23 1381 10/29 1128 11/01 1445 11/03 1440 11/04 1440 11/05 1380 11/07 1400 11/16 1380 11/17 1459 11/22 1412 12/04 1576 12/11 1431
TSP TSP TSP TSP TSP, TSP, TSP, TSP, TSP, TSP, TSP, TSP, TSP, TSP,
Universal Universal Universal Universal Universal Universal Universal Universal Universal Universal
Fig. 2. The locations of the sampling site from the epicenter (Chi-Chi Town).
G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731
PM2:5 , PM2:5±10 particle concentrations were also collected then and compared with TSP in this study. TSP samples were concurrently collected on Glass Micro®ber ®lters by PS-1 samplers. Daily dichotomous sampler (<2.5 and 2.5±10 lm) were collected on Glass Micro®ber ®lters with the universal dichotomous sampler. 2.2. PS-1 sampler The PS-1 (Gps1 Poly-Urethane Filter (PUF) sampler, General Metal Work) consists of nine basic assemblies: Dual chamber, sampling module, ¯ow vent, magnehelic gage, voltage variator, elapsed time indicator, pump, 7-day skip timer, exhaust hose and aluminum shelter. The PS-1 is a completed air sampling system designed to simultaneously collect suspended airborne particles at ¯ow rate up to 280 l/min and the ¯ow rate was adjusted to 200 l/min in this study. The Glass Micro®ber ®lters (diameter 10.2 lm) are used to ®lter the suspended particle in this study. The ®lter paper is put into the dry box for at least 48 h until the humidity equilibrium. Before sampling, the ®lter paper is got from the dry box and is weighted the initial mass. And the ®lter paper is placed onto the dustfree box. Then the ®lter is brought to the sampling site. After sampling, the ®lter is also put into the dust-free box for at least 48 h until the humidity equilibrium and then weighted the ®nal mass. 2.3. Universal sampler The Model 310 Universal Air SamplerTM (USATM ) is a general purpose air sampler for atmospheric aerosol sampling and for mass concentration, and organic or inorganic analysis. The sampler has a design inlet sampling ¯ow rate of 300 l/min. Fully equipped, it includes two virtual impactors for size fractionation of airborne
1729
particles and a PUF sampler for analysis of volatile organic compounds (VOCs) in the air sample. The sampler is provided with an omni-directional inlet, a PM10 (10 lm cut) virtual impactor classi®er, either a PM2:5 or PM10 virtual impactor classi®er, a ®ne particle ®lter and a PUF sampler. This allows operation as a high volume dichotomous sampler for size fractionation of airborne particle in the 0±2.5 lm and 2.5±10 lm aerodynamic size ranges. Air is sampled at 300 l/min from the ambient atmosphere through an omni-directional, cylindrical inlet. Particles greater than 10 lm aerodynamic equivalent diameter are removed from the sampled air stream by the PM10 classi®er and discarded. Particle less than 10 lm ¯ow to the PM2:5 classi®er located downstream. Particles in the 2.5±10 lm range are collected on a 62 165 mm2 ®lter and those smaller than 2.5 mm are collected on a 200 250 mm2 ®nal ®lter. The ®ltered air stream is then directed through the PUF sampler to collect the VOCs in the ®ltered air stream (Universal Air Sampler, 1996).
3. Results and discussion 3.1. The ambient air particle concentrations in the trac site (CCROB) In Fig. 3, it displayed the concentration variation of TSP before and after 921 Taiwan Chi-Chi Earthquake. It was found that the concentration of TSP increases after 921 Taiwan Chi-Chi Earthquake signi®cantly. It also showed the concentration variation of PM10 and TSP at CCROB sampling site after 921 Taiwan Chi-Chi Earthquake. Basically, PM10 and TSP have the same distribution trend. And the average concentration ratio for TSP/PM10 after 921 Taiwan Chi-Chi Earthquake is about 1.5.
Fig. 3. The concentration variation of TSP and PM10 during 921 Taiwan Chi-Chi Town.
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G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731
The ambient air particle concentrations of PM2:5±10 , PM2:5 and TSP are displayed in Table 2. These results indicated that the average PM2:5±10 , PM2:5 and TSP concentrations are 24.6, 58.0 and 106 lg/m3 , respectively. Apparently, the concentration of PM2:5±10 is lower than PM2:5 . It is due to the exhaust of vehicles, and these vehicle emissions were mainly composed of ®ne particles (PM2:5 ) (Fang et al., 1999). The average TSP concentrations before and after 921 Taiwan Chi-Chi Earthquake were 70 and 127 lg/m3 , respectively. It is clearly shown that the average concentration of TSP after 921 Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before 921 Taiwan Chi-Chi Earthquake. 3.2. The ratios of TSP, PM2:5±10 and PM2:5 in the trac sampling site (CCROB) The ratios of TSP, PM2:5±10 and PM2:5 in the trac sampling site (CCROB) after 921 Taiwan Chi-Chi Earthquake were displayed in Table 3. First, the ratios Table 2 TSP, PM2:5±10 and PM2:5 particle concentration in the trac site (CCROB, 1999) Date
Concentration (lg/m3 ) PM2:5±10
Before 921 Earthquake 8/16 ± 8/19 ± 8/26 ± 8/27 ± 9/09 ± 9/10 ± 9/11 ± 9/12 ±
PM2:5 ± ± ± ± ± ± ± ±
Average
60.7 84.1 58.2 43.2 73.8 66.5 96.7 73.3 70
After 921 Earthquake 10/03 ± 10/21 ± 10/23 ± 10/29 ± 11/01 20.6 11/03 16.2 11/04 32.5 11/05 37.2 11/07 19.3 11/16 23.8 11/17 18.3 11/22 24.7 12/04 32.5 12/11 20.6
± ± ± ± 25.4 25.3 92.6 116 29.2 40.7 28.4 61.4 97.3 64.7
Average Total average
TSP
66.3 116 96.8 122 102 84.9 196 232 102 121 115 113 188 123 127
24.6
58.0
106
Table 3 The ratios of TSP, PM2:5±10 and PM2:5 in the trac site after 921 Taiwan Chi-Chi Earthquake (CCROB, 1999) Date
PM2:5 / PM2:5±10
PM2:5 /PM10 (%)
PM2:5 /TSP (%)
11/1 11/3 11/4 11/5 11/7 11/16 11/17 11/22 12/04 12/11
1.2 1.6 2.8 3.1 1.5 1.7 1.6 2.5 3 3.1
55.3 61 74 75.6 60.2 63.1 60.8 71.3 75 75.9
24.8 29.9 47.3 49.8 28.7 33.5 24.6 46 51.8 52.6
Average
2.2
67.2
38.9
of PM2:5 /PM2:5±10 were ranged from 1.2 to 3.1 and were averaged 2.2. These results indicated that the average ®ne particles concentrations were about 2.2 times as that of coarse particles concentration in the trac sampling site (CCROB) after 921 Taiwan Chi-Chi Earthquake. Besides, the average ratios of PM2:5 /PM2:5±10 were higher than previous studies (Fang et al., 1999); increase about 120% which indicated ®ne particle concentration increase compared to the coarse particles concentration at the trac sampling site after 921 Taiwan Chi-Chi Earthquake. Second, the ratios of PM2:5 /PM10 were ranged from 55.3% to 75.9% and were averaged 67.2%. These results were dierent from previous study whose data were collected by day and night time, respectively. And the average ratio of PM2:5 /PM10 in this study increases about 17% compared to that of the previous study (Fang et al., 1999) during the 921 Taiwan Chi-Chi Earthquake period. Finally, the ratios of PM2:5 /TSP were ranged from 24.6% to 52.6% and were averaged 38.9%. These results in the trac sampling site were much higher than those data collected in the rural sites (Fang et al., 1999). This is because that the exhaust of vehicles, and these vehicle emissions were mainly composed of ®ne particles. However, the average ratio of PM2:5 /TSP in this study decreases about 15% compared to those data in the trac sampling site in the previous study (Chang, 1998). Apparently, the ratio of the particles that were less than 2.5 lm in the PM10 increased and the ratio of the particles that were less than 10 lm in the TSP decreased after the 921 Taiwan Chi-Chi Earthquake. To sum up, the ®ne particle concentration (PM2:5 ) increased in the trac site of central Taiwan after 921 Taiwan Chi-Chi Earthquake. And the total suspended particle (TSP) concentration also increased after 921 Taiwan Chi-Chi Earthquake. The particle concentration for PM2:5±10 and PM2:5 compared to the other studies is displayed in Table 4. It
G.-C. Fang et al. / Chemosphere 41 (2000) 1727±1731 Table 4 Particle concentrations compare to other studies Sampling sites
PM2:5 (lg/m3 )
PM2:5±10 (lg/m3 )
Waterrown (Boston) Long Beach (California) GU Site (Brisbane) Kashima (Japan) Quebec (Canada) Montreal (Canada) Taichung (Taiwan) This study (Taiwan)
17.4
17.4
48.6
22.5
7.3
10.4
17.7
17.5
11.9
11.6
20.9
23.7
29.7
25.8
58
24.6
showed that the particle concentration of PM2:5 is signi®cantly higher than those of the other areas while the particle concentration of PM2:5±10 is not dierent from those of the other areas. This is because of the in¯uence of 921 Taiwan Chi-Chi Earthquake. It enhances the ®ne particles concentration (PM2:5 ). 4. Conclusion The main conclusions in this paper are listed as follows: 1. It was found that the concentration of TSP increases signi®cantly after 921 Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after 921 Taiwan Chi-Chi Earthquake were 70 and 127 lg/m3 , respectively. It is clearly shown that the average concentration of TSP after 921 Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before 921 Taiwan Chi-Chi Earthquake. 2. The average ambient air particle concentrations of PM2:5±10 , PM2:5 and TSP were 24.6, 58.0 and 106 lg/m3 , respectively. And the average concentration ratios for TSP/PM10 , TSP/PM2:5 were 1.5, 2.2, respectively after the 921 Taiwan Chi-Chi Earthquake. 3. The average ®ne particles concentration were about 2.2 times as that of coarse particles concentration in the trac sampling site (CCROB) after the 921
1731
Taiwan Chi-Chi Earthquake. Besides, the average ratios of PM2:5 /PM2:5±10 increases about 120% which indicated ®ne particle concentration increase compared to the coarse particles concentration at the trac sampling site after 921 Taiwan Chi-Chi Earthquake. 4. The ®ne particle concentration (PM2:5 ) and the TSP concentration both increase after the 921 Taiwan Chi-Chi Earthquake in the trac site of central Taiwan. Acknowledgements The ®nancial support provided by the Hungkuang Institute of Technology of Humanities and Science Council, through a research contract (HKHSC-90-01) is gratefully appreciated.
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