Modelling lung deposition of fine particulate matter in males and females during urban cycle commuting

Exposure to fine particulate matter (PM_2.5) from urban areas may be modified by structural (e.g., airway anatomy) and functional (e.g., ventilatory pattern) sex-related physiological differences during exercise, resulting in greater PM_2.5 deposition in females versus males. Beyond the total PM_2.5 deposition, further insights concerning regional differences in PM_2.5 deposition are needed to understand females’ hyperresponsiveness to PM_2.5. Thus, a modelling-based analysis of structural and functional characteristics of PM_2.5 deposition in the human respiratory tract was conducted simulating an urban cycle commute of 30 min. Two scenarios were considered to estimate the PM_2.5 deposition: 1) greater minute ventilations in females versus males (p < 0.001); and 2) minute ventilations matched between males and females (p = 0.710). We found that females experience 51.32% and 0.62% greater total PM_2.5 deposition for Scenarios 1 and 2, respectively (both p < 0.001). Regardless of total minute ventilation, there was greater PM_2.5 deposition into the bronchiolar and alveolar region in females compared to males (p < 0.001 for both). These data indicate a greater likelihood of bronchial hyperresponsiveness in females compared with males when exposed to PM_2.5 while cycle commuting in urban areas.