Association between woodsmoke and respiratory health: A Dutch panel study

Background and aim: In the Netherlands household fireplaces are responsible for burning about 1 billion kilograms of wood per year, emitting a significant amount of woodsmoke. Little is known about the respiratory health effects associated with the level of woodsmoke exposure present in the Netherlands. Thus, our aim was to investigate the short-term changes in lung function, respiratory symptoms and medication use associated with short-term changes in woodsmoke exposures in citizens with and without COPD/asthma. The study was co-created with citizens. Methods: We conducted a panel study with repeated observations in 46 adults (11 asthma/COPD) between February and May 2021 in four Dutch cities. Participants were asked to document symptoms and medication use in a daily diary and conduct daily home spirometry measurements in the morning and evening. Woodsmoke exposure was characterized by measuring various exposures at central sites in each study location set-up specifically for the study, and individual woodsmoke perception (smell) recorded in the daily diaries. The association between woodsmoke and health was analyzed using linear and logistic regression, adjusting for time-varying confounders and repeated observations. Results: We found significant positive associations between the specific wood smoke marker levoglucosan and shortness of breath during rest (OR 1.15 (95%CI 1.01, 1.32) per IQR increment for previous day exposure) and extra medication use (OR 1.19 (95%CI 1.07, 1.33) per IQR increment for current day exposure). We found weak associations between woodsmoke and nasal symptoms, and no consistent association with either morning or evening lung function measurements. The associations with levoglucosan remained after the inclusion of generic PM2.5 as a co-pollutant in the statistical models. Conclusion: People experienced more shortness of breath at rest, nasal symptoms and used more medication on days with higher levels of outdoor woodsmoke exposure. Keywords: Woodsmoke, Levoglucosan, Respiratory health, Panel study.