A co-created citizen science project on the short term effects of outdoor residential woodsmoke on the respiratory health of adults in the Netherlands.

Background and aim: Woodsmoke from household fireplaces contributes significantly to outdoor air pollution in the Netherlands. The current understanding of the respiratory health effects of exposure to smoke from residential wood burning is limited. This study investigated the association between short-term changes in outdoor woodsmoke exposure and lung function, respiratory symptoms, and medication use in adults in the Netherlands.

Methods: This study was co-created with citizen scientists and other relevant stakeholders. A panel study was conducted with repeated observations in 46 adults between February and May 2021 in four Dutch towns. Participants recorded their symptoms and medication use in daily diaries, and conducted morning and evening home spirometry measurements. Woodsmoke exposure was characterized by measuring levoglucosan (most specific marker for woodsmoke exposure), black/brown carbon, fine and ultrafine particulate matter at central monitoring sites. Individual woodsmoke perception (smell) was recorded in daily diaries. Linear and logistic regression models were used to investigate the association between respiratory health and woodsmoke exposure. Models were adjusted for time-varying confounders and accounted for repeated observations within participants.

Results: Consistent positive associations were found between levoglucosan and shortness of breath (SOB) during rest and extra respiratory medication use. Odds ratios for current day exposure to levoglucosan were 1.12 (95% CI: 0.97, 1.30) for SOB during rest and 1.19 (95% CI: 1.07, 1.33) for extra medication use, expressed per interquartile range of levoglucosan concentrations (69.16 ng/m³). Positive non-significant associations were found between levoglucosan and nasal symptoms, cough and waking up with SOB. No consistent association was found between levoglucosan and lung function. Associations found between woodsmoke markers, SOB during rest and extra medication use remained after the inclusion of PM_2.5 and UFP in two-pollutant models.

Conclusions: Adults experienced more SOB during rest, nasal symptoms and used more medication to treat respiratory symptoms on days with higher levels of outdoor woodsmoke concentrations.