# 2004 British Occupational Hygiene Society Published by Oxford University Press doi:10.1093/annhyg/meh081 Size Distribution and Speciation of Chromium in Paint Spray Aerosol at an Aerospace Facility

Spray painters are potentially exposed to aerosol containing Cr(VI) via inhalation of chromate-based paint spray. Two field studies were conducted at an aerospace facility to determine the size distribution and speciation of Cr(VI) in paint spray aerosol. Sampled paint products consisted of sparingly soluble strontium chromate in an epoxy resin matrix, a matrix generally known for its durability and toughness. Personal aerosol samples were collected using Sierra Marple personal cascade impactors and analyzed for Cr(VI) and total Cr. The size distribution of total Cr particles in the paint aerosol had a Mass Median Aerodynamic Diameter (MMAD) of 7.5 mm [Geometric Standard Deviation (GSD = 2.7 mm)] in both field studies. The MMAD of Cr(VI) particles was 8.5 mm (GSD = 2.2 mm). Particles>2 mm constituted 90 % or more of the total Cr and the Cr(VI) mass, in all sampled paint aerosols and were lognormally distributed. The target site for respiratory deposition of Cr in the aerosol was estimated based on the mass distribution of Cr according to particle size. On an average, 62 % of the Cr and Cr(VI) mass in the paint aerosol consisted of particles>10 mm. This study showed that 71.8 % of Cr(VI) mass in paint spray aerosol potentially inhaled by a spray painter may deposit in the head airways region. Only 2.0 and 1.4 % of Cr(VI) mass in the paint aerosol may potentially deposit in th