Characterization of exhaled breath condensate (EBC) non-exchangeable hydrogen functional types and lung function of wildland firefighters

Systematic review of impacts of occupational exposure to wildfire smoke on respiratory function, symptoms, measures and diseases

BACKGROUND

Wildfire smoke contains numerous hazardous air pollutants which pose serious health risks to humans. Despite this, there has been a limited focus on the assessment of the acute physiological and longer-term respiratory effects of wildfire exposure on firefighters and other emergency workers. Therefore, we undertook a systematic review of the evidence about the respiratory impacts of occupational wildfire smoke exposure among wildfire fighters (WFF).

METHODS

Eligible studies from Medline, Embase and Scopus databases were included if they described the relationship between wildfire exposure and respiratory function, symptoms, measures and diseases amongst emergency personnel or firefighters who had responded to wildfires.

RESULTS

Twenty-six articles met the inclusion criteria. 24 out of 26 (22 out of 23 moderate/high quality) studies provided evidence of adverse respiratory effects, including reduced lung function, increased airway dysfunction and airway inflammation, upper and lower respiratory tract symptoms and increased asthma incidence related to wildfires or prescribed burns exposure among WFF and police responders. Fourteen out of 19 studies showed statistically significant declines in spirometry measures of lung function (mostly short-term studies). Two studies using complex lung function tests showed a significant effect on peripheral airway function.

DISCUSSION

This review found a convincing body of evidence that occupational exposure to wildfires or prescribed burns has both acute and possibly longer-term respiratory effects among WFFs and some other emergency personnel. Given that these events are increasing, more needs to be done to identify those most at risk and mitigate these risks.

The wildland firefighter exposure and health effect (WFFEHE) study: cohort characteristics and health behavior changes in context

OBJECTIVES

Work is an under-recognized social determinant of health. There is limited research describing US wildland firefighter (WFF) workforce demographics or how to work associates with WFF health behaviors. In this study researchers characterized a WFF cohort and tested hypotheses that WFFs used tobacco, alcohol, and sugar-sweetened beverages (SSBs) differently over the course of the fire season and that different fire crews may exhibit different behavior patterns.

METHODS

Researchers collected data in the field with 6 WFF crews during 2 consecutive fire seasons (2018 and 2019). WFF crews completed questionnaires before and after each season. WFFs with an initial preseason questionnaire and at least 1 follow-up questionnaire were included (n = 138). Descriptive statistics summarized WFFs' baseline demographic, employment, and health characteristics. Linear mixed models were used to test for changes in WFFs' substance use over time and assess crew-level differences. A meta-analysis of WFF longitudinal studies' population characteristics was attempted to contextualize baseline findings.

RESULTS

WFFs were predominately male, less than 35 yr of age, non-Hispanic White, and had healthy weight. Smokeless tobacco use and binge drinking were prevalent in this cohort (52% and 78%, respectively, among respondents). Longitudinal analyses revealed that during the fire season WFFs' use of tobacco and SSBs increased and the number of days they consumed alcohol decreased. Crew-level associations varied by substance. The meta-analysis was not completed due to cross-study heterogeneity and inconsistent reporting.

DISCUSSION

WFF agencies can promote evidence-based substance use prevention and management programs and modify working conditions that may influence WFF stress or substance use.

Evaluation of cytokines in exhaled breath condensate in an occupationally exposed population to pneumotoxic pollutants

The quarrying is considered a precarious occupation with high toxicity, is an informal economic activity that employs low technology, limited protection, and poses a risk to workers and their families. In quarrying, silica dust is generated and there is also occupational exposure to significant mixtures of pneumotoxic pollutants, including mineral dust (crystalline silica, carbon or cement, polycyclic aromatic hydrocarbons (PAHs), solvents, and others, which are aggravated by the lack of use of protective equipment, causing irreversible damage to the worker's respiratory health. Thus, the objective of this work focused on the evaluation of the respiratory health of artisan stonemasons in San Luis Potosí, Mexico through the study of exhaled breath condensate (EBC) (pH, pro-inflammatory cytokines) as well as the study of the exposure to pollutants present in the work area (PAHs, toluene, and 2.5 µm particulate matter) through biomarkers of exposure (hippuric acid and hydroxylated metabolites of PAHs). The results show the presence of crystalline SiO₂ in 100% of the samples analyzed; the PM_2.5 concentrations were 5 to 10 times the permitted levels. Regarding exposure to PAHs, all the stonemasons presented urine concentrations of at least 5 of the OH-PAHs evaluated; 9-OH-FLU occurred at higher concentrations of 171.2 (122.7-279.4) µg L^-1; hippuric acid, which was present in 100% of the workers evaluated in concentrations of 283.4 (27.72-1119) mg L^-1, 100% of which were above the values established for occupational scenarios. The pH values obtained for the EBC samples were presented at an average of 7.07 (6.33-7.66). Pro-inflammatory cytokines were present in 86.1% of the study population. The cytokine that was found in higher concentrations was IL-2, with a mean of 178.01 pg mL^-1 and 3124.01 pg mL^-1 for the pH < 7 and pH > 7 groups, respectively. Some correlations between the cytokines and the exposure biomarkers were presented. Stonemasons are highly exposed to pneumotoxic pollutants and markers of inflammation at the pulmonary level; in addition, a high risk of developing silicosis. Quarrying should be addressed as a carcinogenic activity, which would imply the design of monitoring and control strategies for these pollutants that our country currently lacks, particularly in precarious occupations. It is necessary to develop strategies to protect the health of precarious workers.

Health risks and mitigation strategies from occupational exposure to wildland fire: a scoping review

OBJECTIVES

Due to accelerating wildland fire activity, there is mounting urgency to understand, prevent, and mitigate the occupational health impacts associated with wildland fire suppression. The objectives of this review of academic and grey literature were to: 1. Identify the impact of occupational exposure to wildland fires on physical, mental, and emotional health; and 2. Examine the characteristics and effectiveness of prevention, mitigation, or management strategies studied to reduce negative health outcomes associated with occupational exposure to wildland fire.

METHODS

Following established scoping review methods, academic literature as well as government and industry reports were identified by searching seven academic databases and through a targeted grey literature search. 4679 articles were screened using pre-determined eligibility criteria. Data on study characteristics, health outcomes assessed, prevention or mitigation strategies studied, and main findings were extracted from each included document. The results of this scoping review are presented using descriptive tables and a narrative summary to organize key findings.

RESULTS

The final sample was comprised of 100 articles: 76 research articles and 24 grey literature reports. Grey literature focused on acute injuries and fatalities. Health outcomes reported in academic studies focused on respiratory health (n = 14), mental health (n = 16), and inflammation and oxidative stress (n = 12). The identified studies evaluated short-term outcomes measuring changes across a single shift or wildland fire season. Most research was conducted with wildland firefighters and excluded personnel such as aviation crews, contract crews, and incident management teams. Five articles reported direct study of mitigation strategies, focusing on the potential usage of masks, advanced hygiene protocols to reduce exposure, fluid intake to manage hydration and core temperature, and glutamine supplementation to reduce fatigue.

CONCLUSIONS

While broad in scope, the evidence base linking wildland fire exposure to any one health outcome is limited. The lack of long-term evidence on changes in health status or morbidity is a clear evidence gap and there is a need to prioritize research on the mental and physical health impact of occupational exposure to wildland fire.