Effects of aqueous extracts of PM10filters from the Utah Valley on human airway epithelial cells

Abstract

We hypothesized that the reduction in hospital respiratory admissions in the Utah Valley during closure of a local steel mill in 1986–1987 was attributable in part to decreased toxicity of ambient air particles. Sampling filters for particulate matter < 10 μm (PM₁₀) were obtained from a Utah Valley monitoring station for the year before (year 1), during (year 2), and after (year 3) the steel mill closure. Aqueous extracts of the filters were analyzed for metal content and oxidant production and added to cultures of human respiratory epithelial (BEAS-2B) cells for 2 or 24 h.Year 2 dust contained the lowest concentrations of soluble iron, copper, and zinc and showed the least oxidant generation. Only dust from year 3 caused cytotoxicity (by microscopy and lactate dehydrogenase release) at 500 μg/ml. Year 1 and year 3, but notyear 2, dust induced expression of interleukin-6 and -8 in a dose-response fashion. The effects of ambient air particles on human respiratory epithelial cells vary significantly with time and metal concentrations.