Characteristics and aerosol size distributions of metal-containing paint particles at a spray-painting workplace

Abstract

The health effects of metal-containing paint-particles at various particle-size distributions on workers in a spray-painting workplace at an industrial ventilation equipment manufacturing plant. Samples were collected over 30 working days in 2014. Aerosol samples were collected for 8 h using the 10 impaction stages of a micro-orifice uniform deposit impactor. Metal-containing particles were analyzed using inductively coupled plasma with atomic emission spectroscopy (ICP-AES). Measurement results show that the particles with the highest mass concentrations were PM_>18 (1043.3 ± 412.5 μg m⁻³). The mass ratios of PM₁₀ to total PM ranged from 0.36 to 0.56. The submicron particles (PM₁) and ultrafine particles (PM_0.1) constituted 6.2% and 1.5% of the total PM mass, respectively. The most abundant metal elements in all particle sizes on all sampling days were Pb (55.1 ± 19.5 μg m⁻³) and Fe (42.1 ± 4.1 μg m⁻³). Significantly, the MMD of Cd, Ni, As and Cr of carcinogenic metals were in the range 0.4–2.1 μm (below respirable particle diameters), indicating that 50% carcinogenic metals could possibly be deposited in the non-ciliated gas-exchange regions of the lung. Most metal content contributed approximately 57.48–98.09% to the total PM content in submicron particles (PM₁), except Pb. Cancer risks of carcinogenic metals (Cd, Ni and Cr) in PM₁₀ for paint spraying process workers at the industrial ventilation equipment manufacturing plant nevertheless exceeded 10⁻⁶. In particular, the assessment of health risk of inhaled Cr in ultrafine particle (UFP) fractions was found to be higher than 10⁻⁶, indicating that a carcinogenic health effect existed in the spray-painting workplace.