TD–GC–MS Characterization of Wildfire Smoke Compounds Captured in Respirator Cartridges Used by Wildland Firefighters

Wildfire smoke often gets attention during big, visible events, but we know much less about its longer-term effects on health. To better protect people battling these fires, clearer evidence and improved health guidance are needed, including how best to use masks and respirators. Studying what particles get trapped in respirator filters can also help improve their design so they work better and are more comfortable to wear. A study conducted by researchers at the British Columbia Cancer Research Institute, Thompson Rivers University, and the British Columbia Wildfire Service (all in British Columbia, Canada) measured the chemical composition of wildfire smoke captured by two types of respirator cartridges (containing P100 filters and activated carbon sorbent) used by 19 wildland firefighters in the province. All filters and activated carbon samples were measured using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). A paper based on their work was published in Environmental Research.¹

What Are the Health Impacts of Wildfire Smoke?

Wildfires happen regularly, and over the past century they have been becoming more frequent and more severe, largely because of climate change.² Wildfire smoke is made up of thousands of different chemicals, some in tiny solid or liquid particles, and others as gases. Breathing in this smoke can harm the lungs and heart, and during heavy smoke events, more people end up in the hospital.^3,4While there is clear evidence that wildfire smoke can cause short-term breathing problems, most of what we know relates to brief exposure. Much less is understood about the long-term effects, including whether it contributes to chronic conditions like asthma, COPD, or lung cancer.⁵

What Chemicals are Present in Wildfire Smoke and Are They Captured by Respirator Filters?

In total, the research team detected 496 wildfire smoke compounds on either the filters or the activated carbon samples, with most compounds being oxygenated aromatics (54.9%) for the filters and aromatic hydrocarbons (36.0%) for the activated carbon. A total of 24 compounds were found on publicly available databases of carcinogens or endocrine disruptors. In addition, 17 features were classified as polycyclic aromatic hydrocarbons, which are known carcinogens, abundant in wildfire smoke.¹

“These harmful components,” write the authors of the paper,¹ “were captured on both the filters and activated carbon, which demonstrates the importance of respiratory protection for both gas- and particle-phase pollutants. Elucidating which molecules are captured by current respirator cartridge models can inform future cartridge designs to be optimized for both filtration effectiveness as well as wearability for wildland firefighters and the public.”

The researchers admit to some limitations of their study. One is that the method used cannot detect very small gas-phase chemicals. Some of these compounds either pass through too quickly to be picked up or produce signals that fall outside the instrument’s detection range. For example, a major pollutant in wildfire smoke, formaldehyde, would not be captured by this setup. Other small chemicals like formaldehyde and acrolein are still important to consider when designing better respirator filters, even though they weren’t measured here due to these technical limits. Another point the researchers suggest keeping in mind is that the analysis method was broad and exploratory rather than highly specific. It relies on matching detected signals to reference libraries, which only gives a tentative identification. While many matches were strong, a substantial portion were weaker and should be interpreted with caution. Still, a lower threshold was used on purpose to capture as many potential compounds as possible for this initial investigation.¹

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References

1. Kiland, K. J.; Borden, S. A.; Lichty, D. et al. Chemical Profile of Respirator Cartridges Worn in the Field by Wildland Firefighters. Environ Res. 2026, 124565. DOI: 10.1016/j.envres.2026.124565
2. Jones M. W.; Abatzoglou J.T.; Veraverbeke S. et al. Global and Regional Trends and Drivers of Fire Under Climate Change.Rev. Geophys.2022, 60. DOI: 10.1029/2020RG000726
3. Hughes, F.; Parsons, L.; Levy, J. H. et al. Impact of Wildfire Smoke on Acute Illness. Anesthesiology 2024, 141 (4), 779-789. DOI: 10.1097/ALN.0000000000005115
4. Lei, Y.; Lei, T. H.; Lu, C. et al. Wildfire Smoke: Health Effects, Mechanisms, and Mitigation. Environ Sci Technol. 2024, 58 (48), 21097-21119. DOI: 10.1021/acs.est.4c06653
5. Gao, Y.; Huang, W.; Yu, P. et al. Long-Term Impacts of Non-Occupational Wildfire Exposure on Human Health: A Systematic Review. Environ Pollut. 2023, 320, 121041. DOI: 10.1016/j.envpol.2023.121041