Source apportionment and health effects of particle-bound metals in PM2.5 near a precision metal machining factory

Exposure to particle-bound metals in oil mist and fine particulate matter (PM2.5) may exert harmful health effects. Oil mist and PM samples were collected from metal machining workplaces and areas surrounding a precision machining factory using a multistage impactor. Metal-containing particles were analyzed through inductively coupled plasma - optical emission spectrometry. Mean mass concentrations in PM2.5 were 22.8 +/- 8.2 mu g/m(3) near the precision machinery factory. The average PM2.5 constituted 62.8% +/- 6.2% of the total particles, ranging from 49.6 to 71.0%. The most abundant metal elements in PM2.5 were Fe (293.33 +/- 123.16 ng/m(3)), Zn (292.39 +/- 62.49 ng/m(3)), and Al (115.28 +/- 38.81 ng/m(3)) near the precision machining factory. The three most abundant metal elements are similar to those found in a solvent/water-based cutting oil of metal processing workplace, indicating that observations were influenced by workplace emissions. The total cancer risk of six particle-bound heavy metals (Cr(VI), Co, Ni, As, Cd, and Pb) in PM2.5 via inhalation exposure at the human respiratory systems of residents living near the precision metal machining factory exceeds 10(-6). Source contributions of related metal machining processes were carbon steel/stainless steel machining emissions (17.20 +/- 4.94%) and aluminum alloys/gasoline engine exhaust (27.65 +/- 3.90%) using absolute principal component score receptor model in the surrounding atmosphere of the precision machining factory.