Association between lung function and exposure to smoke among firefighters at prescribed burns

We investigated the short-term effects of exposures to PM3.5, acrolein, formaldehyde, and carbon monoxide on lung function in a group of firefighters performing prescribed burns. Spirometric measurements were made on 65 firefighters at the beginning, midpoint, and end of their work shift, while exposure was measured over the entire day. The interquartile range (IQR) of daily personal PM3.5 exposures was 235 mug/m(3) to 1317 mug/m(3), with an average daily exposure of 882 mug/m(3). Concentrations of acrolein (IQR: [0.002, 0.018] ppm), formaldehyde (IQR: [0.008, 0.085] ppm), and carbon monoxide (IQR: [2.10, 10.48] ppm) were similarly elevated. In this group of firefighters, FEV1 changed by -0.125 L from preshift to postshift (p <.001). We examined the association between this cross-shift lung function decrement and smoke exposure. A 1000 mug/m(3) increase in PM3.5 was associated with a -0.030 L change in the cross-shift FEV1 (95% CI [-0.087, 0.026]). Acrolein, formaldehyde, and carbon monoxide exposure were also not significantly associated with changes in FEV1, FVC, or FEF25-75. We concluded that while firefighters' lung function significantly decreased from preshift to postshift, firefighters exposed to greater concentrations of respiratory irritants did not experience greater lung function decrements. We could not establish a significant link to any of the individual toxic components of smoke we measured.