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Wildland firefighters (WLFFs) are exposed to a mixture of chemicals found in wildland fire smoke and emissions from nonwildland-fuel smoke sources such as diesel. We investigated compositional differences in exposure to particulate matter and explored differences in ventilation rate and potential inhaled dose relative to the work tasks of WLFFs. Repeated measures on ten professional and two volunteer firefighters were collected on prescribed burn and nonburn days. Personal monitoring consisted of real-time and gravimetric fine particulate matter (PM2.5), carbon monoxide (CO), and accelerometer measurements to estimate ventilation rate and potential dose of PM2.5. The fine particulate matter was analyzed for levoglucosan (LG) and light absorbing carbon as a surrogate for black carbon (BC). Breathing zone personal exposure concentrations of PM2.5, LG, BC, and CO were higher on burn days (P < 0.05). Differences in exposure concentrations were observed between burn day tasks (P < 0.05) with firefighters managing fire boundaries (holders) being exposed to higher CO and LG concentrations and less BC concentrations than those conducting lighting (lighters). While no statistical difference in PM2.5 exposure measures was observed between the two tasks, holders in the study tended to be exposed to higher PM2.5 concentrations (~1.4×), while lighters tended to have more inhaled amounts of PM2.5 (~1.3×). Our findings demonstrate possible diversity in the sources of particulate matter exposure at the fireline and suggest the potential importance of using dose as a metric of inhalation exposure in occupational or other settings., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

Objective: A repeated measures study was used to assess the effect of work tasks on select proinflammatory biomarkers in firefighters working at prescribed burns., Methods: Ten firefighters and two volunteers were monitored for particulate matter and carbon monoxide on workdays, January to July 2015. Before and after workshift dried blood spots were analyzed for inflammatory mediators using the Meso Scale Discovery assay, while blood smears were used to assess leukocyte parameters., Results: Firefighters lighting with drip-torches had higher cross-work-shift increases in interleukin-8, C-reactive protein, and serum amyloid A compared with holding, a task involving management of fire boundaries. A positive association between interleukin-8 and segmented-neutrophil was observed., Conclusion: Results from this study suggest that intermittent occupational diesel exposures contribute to cross-work-shift changes in host systemic innate inflammation as indicated by elevated interleukin-8 levels and peripheral blood segmented-neutrophils.

Wildland firefighters in the United States are occupationally exposed to high levels of woodsmoke. Results from experimental studies show that exposure to woodsmoke induces inflammation. A study was conducted to investigate the effect of occupational woodsmoke exposure on inflammatory biomarkers in firefighters working at prescribed burns. Twelve U.S. Forest Service wildland firefighters at the Savannah River Site, South Carolina, volunteered to give blood samples during four prescribed burns between February and March 2011. Twenty-four paired (pre- and post-work shift) blood samples were collected using dried blood spot method to facilitate repeated sample collection. Inflammatory biomarker concentrations in blood samples were measured using the Meso Scale Discovery multi-spot assay system. Concurrent personal PM₂.₅ and CO monitoring of firefighters was conducted. Linear mixed models were used to test whether cross-work shift differences occurred in the following inflammatory biomarkers: IL-1β, IL-8, CRP, SAA, ICAM-1, and VCAM-1. IL-8 showed a significant cross-work shift difference as indicated by a post/pre-work shift ratio of 1.70 (95% CL: 1.35, 2.13; p = 0.0012). Concentrations of IL-8, CRP, and ICAM-1 increased in >50% of samples across work shift. Firefighters who lighted fires as opposed to other work tasks had the largest cross-work shift increase in IL-8. A significant cross-work shift increase in IL-8 in blood samples was observed in healthy wildland firefighters working at prescribed burns. Further research is needed to understand the physiological responses underlying the adverse effects of woodsmoke exposure, and the dose-response relationship between woodsmoke exposure and inflammatory responses.