Association between Outdoor Fungal Concentrations during Winter and Pulmonary Function in Children with and without Asthma

Outdoor fungi are important components of airborne particulate matter (PM). However, the associations between pulmonary function and outdoor fungi are less well known compared to other airborne PM constituents. The objective of this study was to investigate the association between outdoor fungi and pulmonary function in children. Morning peak expiratory flow (PEF) rates were measured daily in 339 schoolchildren (including 36 with asthma), aged 10 to 12, 2 to 27 February 2015. Airborne PM was collected on filters, using a high volume air sampler, each day during the study period. The daily concentration of outdoor fungi-associated PM was calculated using a culture-based method. A linear mixed model was used to estimate the association between PEF values and daily concentrations of outdoor fungi, and the daily levels of suspended PM (SPM) and PM ≤ 2.5 μm (PM2.5). An increase in the interquartile range (46.2 CFU/m³) for outdoor fungal concentration led to PEF changes of -1.18 L/min (95% confidence interval, -2.27 to -0.08) in all children, 1.22 L/min (-2.96 to 5.41) in children without asthma, and -1.44 L/min (-2.57 to -0.32) in children with asthma. Outdoor fungi showed a significant negative correlation with PM2.5 levels (r = -0.4, p = 0.04), but not with SPM (r = ‒0.3, p = 0.10) levels. Outdoor fungi may be associated with pulmonary dysfunction in children. Furthermore, children with asthma may show greater pulmonary dysfunction than those without asthma.