title: Comparison between Thermal Desorption Tubes and Stainless Steel Canisters Used for Measuring Volatile Organic Compounds in Petrochemical Factories.
abstract: OBJECTIVE
  The purpose of this study was to compare thermal desorption tubes and stainless steel canisters for measuring volatile organic compounds (VOCs) emitted from petrochemical factories.
  
  
  METHODS
  Twelve petrochemical factories in the Mailiao Industrial Complex were recruited for conducting the measurements of VOCs. Thermal desorption tubes and 6-l specially prepared stainless steel canisters were used to simultaneously perform active sampling of environmental air samples. The sampling time of the environmental air samples was set up on 6 h close to a full work shift of the workers. A total of 94 pairwise air samples were collected by using the thermal adsorption tubes and stainless steel canisters in these 12 factories in the petrochemical industrial complex. To maximize the number of comparative data points, all the measurements from all the factories in different sampling times were lumped together to perform a linear regression analysis for each selected VOC. Pearson product-moment correlation coefficient was used to examine the correlation between the pairwise measurements of these two sampling methods. A paired t-test was also performed to examine whether the difference in the concentrations of each selected VOC measured by the two methods was statistically significant.
  
  
  RESULTS
  The correlation coefficients of seven compounds, including acetone, n-hexane, benzene, toluene, 1,2-dichloroethane, 1,3-butadiene, and styrene were >0.80 indicating the two sampling methods for these VOCs' measurements had high consistency. The paired t-tests for the measurements of n-hexane, benzene, m/p-xylene, o-xylene, 1,2-dichloroethane, and 1,3-butadiene showed statistically significant difference (P-value < 0.05). This indicated that the two sampling methods had various degrees of systematic errors. Looking at the results of six chemicals and these systematic errors probably resulted from the differences of the detection limits in the two sampling methods for these VOCs.
  
  
  CONCLUSIONS
  The comparison between the concentrations of each of the 10 selected VOCs measured by the two sampling methods indicted that the thermal desorption tubes provided high accuracy and precision measurements for acetone, benzene, and 1,3-butadiene. The accuracy and precision of using the thermal desorption tubes for measuring the VOCs can be improved due to new developments in sorbent materials, multi-sorbent designs, and thermal desorption instrumentation. More applications of thermal desorption tubes for measuring occupational and environmental hazardous agents can be anticipated.
authors.affiliation: 1.Department of Occupational Safety and Health, Chang Jung Christian University, Tainan 71101, Taiwan; 2.Occupational Hygiene Association of Taiwan, New Taipei City 24205, Taiwan;
authors.forename: Cheng-Ping
authors.initials: CP
authors.lastname: Chang
authors.affiliation: 2.Occupational Hygiene Association of Taiwan, New Taipei City 24205, Taiwan; 3.Department of Safety, Health and Environmental Engineering, National United University, Lienda, Miaoli 36063, Taiwan;
authors.forename: Tser-Cheng
authors.initials: TC
authors.lastname: Lin
authors.affiliation: 2.Occupational Hygiene Association of Taiwan, New Taipei City 24205, Taiwan; 4.Department of Public Health, Fu Jen Catholic University, New Taipei City 24205, Taiwan.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Lin
authors.affiliation: 3.Department of Safety, Health and Environmental Engineering, National United University, Lienda, Miaoli 36063, Taiwan;
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Hua
authors.affiliation: 1.Department of Occupational Safety and Health, Chang Jung Christian University, Tainan 71101, Taiwan;
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Chu
authors.affiliation: 1.Department of Occupational Safety and Health, Chang Jung Christian University, Tainan 71101, Taiwan;
authors.forename: Tzu-Yu
authors.initials: TY
authors.lastname: Lin
authors.affiliation: 1.Department of Occupational Safety and Health, Chang Jung Christian University, Tainan 71101, Taiwan;
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Lin
authors.affiliation: 1.Department of Occupational Safety and Health, Chang Jung Christian University, Tainan 71101, Taiwan; 2.Occupational Hygiene Association of Taiwan, New Taipei City 24205, Taiwan; jdwu@mail.cjcu.edu.com.
authors.forename: Jyun-De
authors.initials: JD
authors.lastname: Wu
mesh_terms: D000096:Acetone / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis; D001554:Benzene / Q000032:analysis; D002070:Butadienes / Q000032:analysis; D002617:Chemical Industry; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D015386:Hazardous Substances / Q000032:analysis; D006801:Humans; D016273:Occupational Exposure / Q000032:analysis; D013193:Stainless Steel; D055549:Volatile Organic Compounds / Q000032:analysis*; D014992:Xylenes / Q000032:analysis
chemical_list: D000393:Air Pollutants; D002070:Butadienes; D015386:Hazardous Substances; D055549:Volatile Organic Compounds; D014992:Xylenes; D013193:Stainless Steel; D000096:Acetone; C031286:4-xylene; D001554:Benzene; C031763:1,3-butadiene
keywords: air sampling; consistency; petrochemical factory; stainless steel canister; thermal desorption tube; volatile organic compounds