Unique and shared patterns of chemosensory dysfunction distinguish chronic COVID-19 and aspirin-exacerbated respiratory disease.

Per‐ and polyfluoroalkyl substances (PFAS) include thousands of anthropogenic chemicals containing highly stable carbon‐fluorine bonds [, ]. Despite their widespread use in industrial and consumer applications, only a handful of these chemicals have been systematically studied [, ]. PFAS are of public health concern because several long‐chain PFAS are detected in the blood of nearly all US residents and are associated with numerous adverse health outcomes including lipid dysregulation, increased incidence of certain cancers, immune modulation, and endocrine disruption [, , ]. Among general populations, ingestion of contaminated water and food, inhalation of particles, and dermal absorption of PFAS‐containing products are thought to be the primary PFAS exposure pathways []. However, the relative importance of these exposure pathways varies by physiological, geographic, and temporal factors []. Some populations such as firefighters may be additionally exposed to PFAS through their occupations [, ]. Firefighters may be exposed to PFAS through use of class‐B aqueous film‐forming firefighting foams (AFFF), combustion products, and possibly their firefighter protective clothing (turnout gear) [, , , , ]. Firefighters have been found to have higher than average serum concentrations of several PFAS compounds (including perfluorooctanoic acid [PFOA] [, , ], perfluorooctane sulfonic acid [PFOS] [, , ], perfluorohexane sulfonic acid [PFHxS] [, , , , , ], and perfluorononanoic acid [PFNA] [, , ]) compared to reference populations. However, there is heterogeneity in the concentrations of PFAS compounds reported in firefighter biomonitoring studies, which may be attributable to multiple factors such as changes in exposure over time or by geographic, individual, and physiological factors [, , ]. Of the over one million firefighters in the United States, 65% are volunteers []. However, despite volunteer firefighters having the same responsibilities as career firefighters [], few studies have assessed PFAS serum profiles in volunteer firefighters. While volunteer firefighters anecdotally report less frequent AFFF use and may spend less time at their fire stations than career firefighters, they may have other PFAS exposure pathways. Volunteer firefighters tend to be under‐resourced compared with career firefighters []. For example, their turnout gear may be older or fit poorly, opening potential fire scene and gear‐related exposure pathways []. Many volunteer fire departments do not have gear (extraction) washers or showers in the fire station []. Many volunteer firefighters do not have a second set of turnout gear to use while the first one is being cleaned, thus their gear may be laundered less frequently. Unlike many career fire stations, volunteer fire stations may not be equipped with separate storage areas for gear or equipment that may off‐gas PFAS or generate dust containing PFAS. Volunteer fire departments may not have, or may not regularly update, standard operating procedures for post‐contamination exposure reduction. Volunteer firefighters may also use personal vehicles to transport themselves or their gear prior to complete decontamination. Volunteer firefighters may perform multiple or overlapping duties at a fire scene when few members respond to a call, possibly increasing the number of hours spent on scene. These factors can lead to a build‐up of contaminants and prolong potential exposure.