Uncorrected Author Proof Work xx (2020) x–xx DOI:10.3233/WOR-203272 IOS Press 1 Chemical pollutants in the respiratory zone of welders: Determination of concentrations and hazard analysis 1 2 3 Younes Mehrifar, Sara Karimi Zeverdegani and Masoud Rismanchian ∗ 4 Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran 5 6 Received 4 June 2019 7 Accepted 23 June 2020 8 Abstract. 9 BACKGROUND: Welding pollutants have potentially dangerous effects on the health of welders. Analysis of exposure risks is an appropriate method for industrial hygiene occupational exposure. 10 11 OBJECTIVE: The present study aimed to determine the concentrations of exposure and risk evaluation of welders to fumes and gases in three common types of welding including Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW). 12 13 14 METHODS: This cross-sectional study was carried out at a steel company. Samples were taken from manganese, chromium and nickel fumes with NIOSH 7300 method and for NO, NO2, CO and O3 gases using direct reading instruments. SQRCA method was used to assess the level of exposure risk. 15 16 17 RESULTS: Our study showed that the highest and lowest concentrations of exposure to gases were observed in MIG and GTAW welding, respectively. Also, the highest and lowest concentrations of exposure to metals were observed in SMAW and GTAW processes, respectively. Mean exposure to M, Cr and Ni metals was 2.302, 3.195, and 1.241 mg/m 3 , respectively. Also, mean exposure to CO, NO, NO2 and O3 was 43.05, 27.88, 4.30, and 0.41ppm, respectively. Results of risk analysis showed that O3, NO2 and Cr had high and very high risk levels in all welding processes. 18 19 20 21 22 CONCLUSIONS: MIG and SMAW welders have a high occupational exposure to metal and toxic gases in welding. Preventive measures such as assessment of workplace air, installation of the ventilation systems, and providing appropriate respiratory protection devices for welders should be taken. 23 24 25 Keywords: Risk assessment, fume, gas, steel industry, welders 26 1. Introduction 27 The welding process is available in most small and 28 large workplaces and is used to repair problematic 29 parts [1]. The use of welding has increased in recent 30 years. Welding is defined as the process of connecting 31 ∗ Address for correspondence: Masoud Rismanchian, Depart- ment of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran. E-mail: rismanchian@hlth.mui.ac.ir. two pieces of metal to each other by metal melting 32 called the electrode. There are different types of weld- 33 ing. In the process of Shielded Metal Arc Welding 34 (SMAW), a coalescence of metals are produced by 35 heating them with an arc between a covered metal 36 electrode and the work [2]. The SMAW process is 37 popular in the industry because it is cheap, can boil 38 most of the metals and alloys, and can be easily imple- 39 mented in harsh environments [3]. 40 In the process of Gas Metal Arc Welding (GMAW) 41 and Gas Tungsten Arc Welding (GTAW), shielding 42 1051-9815/20/$35.00 © 2020 – IOS Press and the authors. All rights reserved