Exposures and Cross-shift Lung Function Declines in Wildland Firefighters

Abstract

Respiratory problems are common among wildland firefighters. However, there are few studies directly linking occupational exposures to respiratory effects in this population. Our objective was to characterize wildland fire fighting occupational exposures and assess their associations with cross-shift changes in lung function. We studied 17 members of the Alpine Interagency Hotshot Crew with environmental sampling and pulmonary function testing during a large wildfire. We characterized particles by examining size distribution and mass concentration, and conducting elemental and morphological analyses. We examined associations between cross-shift lung function change and various analytes, including levoglucosan, an indicator of wood smoke from burning biomass. The levoglucosan component of the wildfire aerosol showed a predominantly bimodal size distribution: a coarse particle mode with a mass median aerodynamic diameter about 12 μm and a fine particle mode with a mass median aerodynamic diameter < 0.5 μm. Levoglucosan was found mainly in the respirable fraction and its concentration was higher for fire line construction operations than for mop-up operations. Larger cross-shift declines in forced expiratory volume in one second were associated with exposure to higher concentrations of respirable levoglucosan (p < 0.05). Paired analyses of real-time personal air sampling measurements indicated that higher carbon monoxide (CO) concentrations were correlated with higher particulate concentrations when examined by mean values, but not by individual data points. However, low CO concentrations did not provide reliable assurance of concomitantly low particulate concentrations. We conclude that inhalation of fine smoke particles is associated with acute lung function decline in some wildland firefighters. Based on short-term findings, it appears important to address possible long-term respiratory health issues for wildland firefighters. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resources: a file containing additional information on historical studies of wildland fire exposures, a file containing the daily-exposure-severity questionnaire completed by wildland firefighter participants at the end of each day, and a file containing additional details of the investigation of correlations between carbon monoxide concentrations and other measured exposure factors in the current study.].

A cross‐sectional survey of occupational history as a wildland firefighter and health

“…Although a number of studies have examined short‐term and cross‐seasonal effects of wildland firefighting, the results reported in this cross‐sectional study are the first to shed light on the potential health consequences of longer durations of wildland firefighting experience. Most studies of WLFF health have emphasized respiratory effects [Betchley et al, , Gaughan et al, , ]. In the relatively young population included here, the prevalence of most self‐reported measures of chronic respiratory illness (e.g., chronic obstructive pulmonary disease) was extremely low.…”

“…It is critical to understand how these exposures affect long‐term health. Wildland firefighters (WLFFs) are exposed to numerous air pollutants including particulate matter (PM) [Gaughan et al, ], nitrogen oxides [Naeher et al, ], benzene [Booze et al, ], carbon monoxide [Adetona et al, ], silica [Harrison et al, ], and polycyclic aromatic hydrocarbons (PAHs) [Adetona et al, ]. Although the long‐term risks to health associated with occupational exposure to wildland fire events are not well‐characterized, each of these pollutants has known long‐term health consequences.…”

Arterial stiffness, oxidative stress, and smoke exposure in wildland firefighters

“…Measurement of levoglucosan, a sugar anhydride by-product of incomplete combustion of cellulose, may be used to indicate relative exposure to products of pyrolysis from burning biomass [Simoneit et al, 1999]. A recent study examined personable exposure to airborne respirable levoglucosan using a Dorr-Oliver cyclone and air sampling pump, and cross-shift changes in lung function in a population of 17 wildland firefighters for 4 days at a large wildland fire [Gaughan et al, 2014]. The authors reported that levoglucosan was found mainly in the respirable fraction, defined as under 2.5 μm, with higher concentrations during fireline construction than in mop-up operations.…”

Evaluation of wildland fire fighter exposures during fuel reduction projects.

“…Aside from CO, wildfire smoke contains particulates of 2.5 microns in diameter, polyaromatic hydrocarbons, and levoglucosan, a product of combustion of cellulose. Several studies have shown that these products of wood combustion may decrease lung function in wildland fire fighters across fire seasons [Adetona et al 2013;Gaughan et al 2014;Hagberg et al 1985;Harrison et al 1995]. The extent to which of these specific factors may impact lung function may vary between individuals.…”