Research Trainee: Anthony Akande, PhD Student, The Ohio State University

Principal Investigator: Olorunfemi Adetona, Associate Professor, The Ohio State University

Although, cardiac events are the major cause of on-the-job deaths among wildland firefighters (WFFs) in the United States, no systematic study of the cardiac effects of the occupation has been conducted. However, WFFs are occupationally exposed to multiple cardiovascular disease (CVD) risk factors during firefighting. Such exposures are likely to increase because of growing wildfire activity and increased use of prescribed burns to manage the landscape. Therefore, the proposed study will leverage available samples and investigate the impact of wildland firefighting on cardiac health. Changes across the wildland fire season in biomarkers of cardiac injury including cardiac troponin T (cTnT) and N-terminal pro-B type natriuretic peptide (NT-proBNP) will be measured among WFFs, correlated with wildland firefighting activity during the season, and compared with corresponding changes in emergency medical technicians (EMTs). The findings of the study will inform future research to identify specific workplace and non-occupational hazards that impair cardiac health among WFFs, contribute towards the improvement of risk assessment of wildland firefighting, and inform risk mitigation strategies. The training afforded by the project will equip the trainee, Anthony Akande, with requisite skills to build a career in research about the occupational health of public safety workers.

Research Trainee: Judith Arthur, PhD Student, University of Cincinnati

Principal Investigator: Sripriya Shankar Nannu, Assistant Professor, University of Cincinnati

Climate change, characterized by rising temperatures and altered precipitation patterns, exacerbates wildfire risk and severity. These fires, in turn, release large amounts of greenhouse gases, contributing to further climate change and creating a vicious cycle. Notably, an average of 70,000 wildfires occur annually in the USA, and over a 15-year period (2006-2020), ~15,000 deaths have been estimated due to exposure to fine particulate matter (PM2.5) from wildfire smoke. Given the increasing severity of wildfires and their impact on the economy, ecosystems, and human health, it is considered one of the major issues in the USA.

Among the different stages of combustion (pre-ignition, flaming, transition, and smoldering), smoldering is the most dangerous phase because (a) it is the longest stage of a fire and can take several weeks to fully extinguish all embers from a large fire; (b) even a small increase in oxygen levels can reinvigorate the fire; and (c) a greater mass of organic aerosols (both primary and secondary) is released into the atmosphere. Since temperatures are low during smoldering (compared to flaming), aerosol emissions readily interact with other atmospheric components under favorable conditions, thereby altering the climate and consequently affecting public health.

Although extensive research exists on the chemical components of wildfire smoke, the biological components, primarily bioaerosols, remain underexplored. Recent studies have confirmed that wildfire smoke is an important medium for aerosolizing and transporting bioaerosols, and biomass burning is a key source of viable bioaerosols in urban and residential atmospheres. Once transported, bioaerosols can pose significant health risks to occupational workers (such as firefighters, emergency responders, and outdoor workers) and the public. Urgent research is needed to assess microbial exposure risks and inform public and occupational health policies, given the lack of standard protocols or limits for bioaerosols.

Our study aims to simulate wildland fire in a controlled chamber to provide firsthand information on emissions and the survivability of bioaerosols under these conditions. We hypothesize that smoldering generates significant concentrations of microorganisms from the fuels, including those in respirable fractions (<10 μm), and that a substantial proportion of bioaerosols will retain viability during this phase. By integrating aerosol measurements with microbiological techniques, we believe our findings will advance the field of Pyroaerobiology and help inform health policies and air quality standards to reduce risks among exposed populations.

Research Trainee: Ga-Young Lim, PhD Student, Indiana University

Principal Investigator/Mentor: Zachary Schlader, Associate Professor, Indiana University

To better protect workers from occupational heat stress, this project will examine whether repeated heat exposure during construction work leads to measurable heat acclimatization. Heat acclimatization is an established strategy for mitigating the adverse health, safety and performance effects of heat exposure, but most evidence comes from controlled laboratory or exercise-based studies. Less is known about how heat acclimatization develops in real occupational settings, where workers experience variable heat exposure, changing work intensities, long shifts, and inconsistent rest opportunities.

This one-year pilot project will analyze data currently being collected from up to 160 construction workers monitored continuously during work across a 6-month heat season (March–September) in Louisiana, USA. Wearables will be used to estimate core temperature and characterize work intensity and work-rest patterns based on physiological data. Thermal dose will be calculated as cumulative heat strain during work shifts and used to examine whether repeated occupational heat exposure is associated with heat acclimatization.

The study has three aims: (1) to quantify daily and cumulative thermal dose across the construction heat season; (2) to determine whether heat acclimatization occurs as thermal dose increases (3) to examine whether potential adaptation benefits are offset by higher work intensities or shorter rest periods, a pattern we define as adaptation–workload mismatch.

This work addresses a key gap: occupational heat acclimatization schedules are widely recommended but not well validated in worker populations. By linking thermal dose, work intensity, rest patterns and physiological strain under real construction conditions, this study will provide preliminary field evidence to inform heat stress monitoring, acclimatization guidance, and work-rest practices.

Research Trainee: Ryleigh Turner, PhD Student, Purdue University

Principal Investigator/Mentor: Ellen Wells, Professor, Purdue University

The overall goal of this research project is to evaluate occupational exposure to lead and benzene at a small regional airport that primarily uses leaded aviation gasoline (avgas). Avgas is a substantial source of benzene and is the only remaining transportation fuel containing lead in the United States. It is used widely in small pistonengine aircraft, which are often used in general aviation and flight instruction at small airports. This includes the Purdue University Airport (LAF), which uses 100 Octane Low Lead (100LL) avgas. Despite the well-established toxicity of lead and benzene, occupational exposure data for general aviation ground workers remain scarce. This pilot study uses a repeated-measures design to characterize lead and benzene concentrations among Purdue Aviation employees (n=15 participants). Data will be collected using a survey, personal air sampling, dermal wipe sampling, and dried blood spots. Environmental samples will be collected every two months over an eight-month period (N=75 samples). Lead samples will be analyzed by X-ray fluorescence (XRF), and benzene samples will be analyzed by gas chromatography with flame ionization detection (GC-FID). Differences in lead and benzene concentrations across job functions (fuel loaders, aircraft mechanics, and administrative staff) will be determined using repeated-measure ANOVA tests to account for time-related correlation. Lead and benzene concentrations will also be compared to standard occupational limits. It is anticipated that findings will address a critical data gap of occupational health concerns among small airport workers, contribute to recommendations for evidence-based occupational health policy, and provide the baseline data needed to protect an understudied workforce as lead is phased out of aviation fuels.

Research Trainee: Xin Zhang, Research fellow, Department of Environmental Health Sciences, University of Michigan

Principal Investigator: Rick Neitzel, Professor, Department of Environmental Health Sciences, University of Michigan

Hearing protector often achieve less noise attenuation in the field than lab-tested values suggest. Although hearing conservation programs are widely implemented and audited for compliance, limited field data describe what is the actual reduction in practice. This gap is particularly relevant for workers who use vibrating power tools, as vibration-related tasks may disrupt hearing protector fit and lower achieved attenuation, and hand-arm vibration (HAV) in combination with noise has been linked to increased risk of noise-induced hearing loss.

This pilot project will conduct a secondary analysis of de-identified noise and HAV data collected during routine field use of intelligent hearing protectors equipped with inside and outside microphones. The data, provided by an industry collaborator, include shift-long records of sound levels sampled external to, and simultaneously underneath, hearing protectors every 10 seconds, as well as tool usage records with tool-level vibration magnitude. Aim 1 will describe real-world noise exposure and hearing protector effectiveness by occupation and industry, comparing externally measured noise levels with existing U.S. exposure estimates obtained from the publicly available NoiseJEM created previously by our research team. Aim 2 will evaluate whether tasks involving HAV use are associated with lower achieved attenuation, using paired within-shift comparisons and mixed-effects regression models. An exploratory aim will identify work contexts where hearing protection effectiveness may fall short of needed levels, generating hypotheses for future controlled studies. Findings will extend the NoiseJEM data repository by adding a supplementary dimension of hearing protector effectiveness under field conditions.

This project will provide the research trainee with hands-on experience in wearable sensor-based exposure assessment, complex field data management, and industry collaboration, supporting her development toward an independent research career in occupational health and safety. Preliminary results will inform future grant applications for prospective studies of integrated noise monitoring and hearing protection strategies in U.S. workplaces.