[01] Azimi Pirsaraei Seyed Reza, Occupational Health Engineering Department, Faculty of Medical Sciences, Tarbiat Modares University, Jalal Ale Ahmad Highway, Tehran, IR Iran. [02] Asilian Mahabadi Hasan, Occupational Health Engineering Department, Faculty of Medical Sciences, Tarbiat Modares University, Jalal Ale Ahmad Highway, Tehran, IR Iran. [03] Jonidi Jafari Ahmad, Environmental Engineering Department, Faculty of Health, Iran University of Medical Sciences, Shahid Hemmat Highway, Tehran, IR Iran. [04] Mehrasbi Mohammad Reza, Environmental Engineering Department, Faculty of Health, Zanjan University of Medical Sciences, Zanjan, IR Iran.

A common measurement device for evaluating the volatile organic compounds (VOCs) concentration is a gas chromatograph generally equipped with a flame ionization detector (GC-FID). However, there are some limitations in working with these equipments including accessibility of them, need to highly trained operators, and the high cost of sample analysis. These restrictions result in the replacement of some direct reading methods, including the use of photoionization detector (PID).The aim of this study was to evaluate the performance of PID as a substitution for GC-FID in the measurement of toluene vapors in a continuous flow system. An experimental set up was designed for generating the toluene vapors known concentrations at 5, 20, 50, 100, 200, 500 and 1000 ppm. The concentrations were measured with both a PID system and a reference method. The correlation coefficients for the concentrations of toluene vapors at 5 to 100 ppm; at 100 to 1000 ppm and at 5 to 1000 ppm were 0.999, 1.0 and 0.999 respectively. Paired t test indicated a significant difference (P < 0.02) between the toluene concentrations in NIOSH reference method and the PID system at higher than 50 ppm but at 4 ppm and 20 ppm, there was no significant difference (P >0.05). In both methods, the coefficient of variation was less at concentrations greater than 100 ppm, thus the response of both devices had fewer variations, in comparison with the concentrations lower than 100 ppm. The correction factor for the PID system was obtained 1.05.Although the results the PID system was different from NIOSH reference method, the PID system response was linear. Thus, in this study the results were acceptable for the toluene vapors generated in a continuous flow system that was measured with the PID system.

Toluene, Gas Chromatography, Flame Ionization Detector, Photo Ionization Detector, Direct Reading Method

[01] http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=160&tid=29, [Last accessed on 2014 Sep 04]. [02] http://www.epa.gov/ttnatw01/hlthef/toluene.html , [Last accessed on 2014 Sep 04]. [03] Barzegar Shangol A, Mortazavi, SB, Asilian H, Kazemian H. Elimination of toluene vapors using natural zeolite treated by copper oxide. J Kermanshah University Med Sci. 2013; 17: 423-30. [04] Barzegar Shangol A, Mortazavi, SB, Asilian H, Kazemian H. Catalytic degradation of toluene on manganese oxide catalyst loaded on a natural zeolite support. Scientific Journal of Review. 2014; 3: 345-52. [05] Mathur AK, Majumder CB, Chatterjee Sh. Combined removal of BTEX in air stream by using mixture of sugar cane bagasse, compost and GAC as biofilter media. J Hazard Mater. 2007; 148:64-74. [06] IARC monograph. Toluene, monographs.iarc.fr/ENG/Monographs/vol71/mono71-36.pdf. [07] ACGIH. Threshold limit values for chemical substances and physical agents and biological exposure indices (TLVs and BEIs). Cincinnati, OH, USA, 2014. [08] Samarghandi M R, Babaee SA, Ahmadian M , Asgari G, Ghorbani Shahna F , Poormohammadi A. Performance Catalytic Ozonation over the Carbosieve in the Removal of Toluene from Waste Air Stream. Journal of Research in Health Sciences. 2014; 14: 227-32. [09] Rismanchian M, Golbabaei F, Mortazavi Y, Pourtaghi GH, Rahimi Foroushani A. Evaluation of photoionization detector performance in photocatalytic studies for removing volatile organic compounds. Int J Env Health Eng. 2012; 13:1-7. [10] Rismanchian M, Jafar Akbari, Keshavarzi R. Photocatalytic removal of gaseous toluene by titanium dioxide coated on nickel foam: Influence of relative humidity and toluene concentration. Int J Env Health Eng. 2014; 29:76-81. [11] The PID handbook, Theory and Applications of Direct-Reading Photoionization Detectors (PIDs). 3th ed. RAE Systems Inc, San Jose: CA; 2013. [12] Coy JD, Bigelow PL, Buchan RM, Tessari JD, Parnell JO. Field evaluation of a portable photoionization detector for assessing exposure to solvent mixtures. Am Ind Hyg Assoc J. 2000; 61: 268-74. [13] Drummond I. “On-the-fly” calibration of direct reading photoionization detectors. Am Ind Hyg Assoc J. 1997; 58: 802-22. [14] Poirot P, Subra I, GÉRardin F, Baudin V, Grossmann S, HÉRy M. Determination of Short-term Exposure with a Direct Reading Photoionization Detector. Ann Occup Hyg 2004; 48: 75-84. [15] Barsky JB, Que Hee SS, Clark CS. An evaluation of the response of some portable, direct-reading 10.2 eV and 11.8 eV photoionization detectors and a flame ionization gas chromatograph for organic vapors in high humidity. Am Ind Hyg Assoc J. 1985; 46: 9-14. [16] Lee IN, S.S. Que Hee SS, Clark CS. Additivity of detector responses of a portable direct-reading 10.2 eV photoionization detector and a flame ionization gas chromatograph for atmospheres of multi-component organics: Use of PID/FID ratios. Am Ind Hyg Assoc J. 1987; 48: 437-41. [17] Mofidi AA, Asilian H, Jonidi Jafari A. Adsorption of volatile organic compounds on fluidized activated carbon bed. Health scope. 2013; 2:84-89. [18] Dean JA. Lange's Handbook of Chemistry. In: Physical Properties, Vapor-Pressure Equations. 15th ed. New York: McGraw-Hill; 1999. P. 5.30-56. [19] NIOSH. Hydrocarbon aromatics, reference method 1501. Available from: http:// www.cdc.gov/niosh/nmam/ [Last accessed on 2014 June 18]. [20] Coffey CC, LeBouf RF, Lee L, Slaven JE, Martin S. Effect of Calibration and Environmental Condition on the Performance of Direct-Reading Organic Vapor Monitors. J Occup Environ Hyg. 2012; 9: 670-80. [21] LeBouf RF, Slaven JE, Coffey CC. Effect of calibration environment on the performance of direct-reading organic vapor monitors. J Air Waste Manag Assoc. 2013; 63:528-33. [22] Bjarke Mølgaard , Anna-Kaisa Viitanen, Anneli Kangas, Marika Huhtiniemi, et al. Exposure to Airborne Particles and Volatile Organic Compounds from Polyurethane Molding, Spray Painting, Lacquering, and Gluing in a Workshop. Int. J. Environ. Res. Public Health.2015; 12: 3756-3773. [23] Kátia Duarte, Celine I.L. Justino,Ana Cristina Freitas, Armando C. Duarte, Teresa A.P. Rocha-Santos. Direct-reading methods for analysis of volatile organic compounds and nanoparticles in workplace air. TrAC Trends in Analytical Chemistry. 2014; 53: 21–32. [24] Catalina Espino Devine, Peter Bennett, Karen Synowiec,Sheldon Nelson, Rachel Mohler and Murray Einarson. Development and Testing of a Field Screening Method Based on Bubbling Extraction and Photoionization Detection for Measurement of Benzene and Total VOCs. Ground water Monitoring & Remediation. 2014; 34: 95–104. [25] Sedighe Atrkar Roshan, Amir Abbas Mofidi. Comparison of Fixed and Fluidized Beds Adsorber with Economic, Engineering and Environmental approach. International Journal of Occupational Hygiene. 2014; 6:165-174.