Synergistic Effects of Ozone Reaction Products and Fine Particulate Matter on Respiratory Pathophysiology in Children with Asthma
Linchen He, Charles J. Weschler, Glenn Morrison, Feng Li, Yinping Zhang, Michael Bergin, Marilyn Black, Junfeng Zhang
Abstract
High Resolution Image Download MS PowerPoint Slide After being transported from outdoor to indoor environments, a large portion of ozone (O 3 ) reacts with indoor chemicals to generate O 3 reaction products. A fraction of these products can partition to fine particulate matter (PM 2.5 ). Hence, we hypothesize that PM 2.5 serves as a carrier to deliver O 3 reaction products to the deep lung, leading to synergistic adverse pulmonary effects. In a panel study involving 43 children with asthma, each was assessed 4 times (2-week interval) for biomarkers of respiratory pathophysiology and personal exposures to PM 2.5 and O 3 . We also assessed O 3 loss exposures, calculated by taking the difference between the outdoor and indoor O 3 concentrations, which was proportional to the net exposure to O 3 reaction products. We found the adverse effects of O 3 loss exposure on biomarkers of pulmonary inflammation, airway (especially lower airway) mechanics, and spirometry lung function were greater at higher PM 2.5 exposure levels. We also found that the adverse effects of PM 2.5 exposure were greater at higher O 3 loss exposure levels. This suggests an additional mechanism for the synergistic pulmonary effects: PM 2.5 predisposes the lung to be more susceptible to O 3 reaction products and vice versa. However, our data is limited in differentiating the two potential mechanisms.