Plasma cutting and exposure to PM2.5metal aerosol in metalworking, Almaty, Kazakhstan, 2020

Objectives Little is known regarding the metal working subprocesses that determine exposures in the workplace primarily because their segregation from the main process is rather difficult in real-life occupational settings. The present study aimed to identify the subprocesses in a metalworks plant with high personal exposure to particulate matter (PM 2.5) metal aerosol in order to plan future risk reduction interventions. Methods A total of eighty 8-hour PM 2.5 metal aerosol samples from the breathing zone of four workers in each of four major operations (plasma cutting, machine operating, assembling and welding) were collected in a metalwork plant in Almaty in January to June 2020. Minimal, maximal, time-weighted average PM 2.5 metal aerosol mass concentrations were recorded with TSI SidePak AM520 personal aerosol and analysed using analysis of variance (ANOVA) after normalisation. Results The overall sampling time was 640 hours. Maximal 1 min and geometric mean PM 2.5 concentrations were 8.551 and 1.7268 mg/m 3 in plasma cutting; 4.844 and 0.9343 mg/m 3 in machine operating; 2.993 and 0.6898 mg/m 3 in assembling; and 2.848 and 0.4903 mg/m 3 in welding. Using a Tukey-Kramer test after a one-way ANOVA, plasma cutting concentrations were significantly higher compared with all other operations (F-ratio 29.6, p<0.001). The fold-range containing 95% of the total variability (R 0.95) from all samples was 12.5. Conclusions The highest PM 2.5 concentrations were found in plasma cutting, potentially elevating the risk of systemic inflammatory effects. © Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.