Household wood smoke exposure, lung black carbon deposition, and genomic instability in U.S. Mountain West Residents

Household wood-burning is common in the U.S. Mountain West, yet it remains unknown whether typical U.S. exposure increases lung black carbon deposition or genomic instability. We conducted a multi-site pilot panel study of 109 woodstove users in New Mexico (NM), Alaska, Idaho, and Montana (2022–2024) during high-heating (greatest heating demand) and low-heating (mild heating demand) seasons. The NM site additionally included a non-heating season (no heating demand) and a comparison group of non-woodstove users ( n = 18) assessed during the high-heating season. Key study elements includes indoor PM 2.5 , wood-burning behaviors, macrophage carbon load, and blood biomarkers of genomic instability. NM homes using wood-burning stoves had significantly higher indoor PM 2.5 during the high-heating season (21.95 µg/m³) than during the non-heating season (4.10 µg/m³, p = 0.039) or non-woodstove homes during the high-heating season (3.79 µg/m³, p = 0.018). Moreover, woodstove users in NM had ~three-fold higher numbers of particles (NoP) in airway macrophages in high-heating season (1.88) than in non-heating season (0.61, P = 0.014) or non-users in high-heating season (0.79, p = 0.05). Those who routinely tended woodstoves showed higher area of particles (AoP) and percentages of cell occupied by carbons (PCOC) across all four sites ( p < 0.05) and higher urinary levoglucosan in NM (0.23 versus 0.14 µg/g creatinine, p = 0.027) than those who never/seldomly did. Older woodstoves (≥ 20 years) were consistently associated with higher AoP, NoP, and PCOC. In NM, blood from woodstove users exhibited significantly higher frequencies of micronuclei, nuclear buds, and nucleoplasmic bridges. For example, micronuclei frequency increased from 14.46 in non-heating season to 23.08 per 1000 binucleated cells in high-heating season ( p < 0.001). Overall, household wood-burning increases indoor PM 2.5 , lung-deposited black carbon, and genomic instability among the U.S. Mountain West residents. Replacing woodstoves older than 20 years and improving stove-tending practices may be promising intervention targets. Not applicable.