Personal exposure to electrophilic compounds of fine particulate matter and the inflammatory response: The role of atmospheric transformation

Abstract

Atmospheric oxidation can produce electrophilic compounds, altering the health effects induced by fine particulate matter (PM2.5); however, little is known about these electrophilic compounds or their health effects. Using electron capture negative ionization, we systematically detected 301 electrophilic compounds from personal PM2.5 samples in a panel study in urban Beijing. Most were oxygen-containing compounds with 3–17 double bond equivalents (DBE), suggesting the dominance of oxidized aromatic structures. Over 64% of the species, mostly outdoor-originated, were associated with inflammatory cytokines in both exhaled breath condensate and serum. Primary components of polycyclic aromatic hydrocarbons (PAHs) and high-DBE oxygenated PAHs, mainly from fossil fuel combustion, were positively associated with interleukin (IL)− 6, a cytokine related to oxidative homeostasis. Oxidized secondary species, particularly maleic and phthalic anhydrides, were negatively associated with IL-2/IL-8, which changed by − 3.8% to − 16.4% per one-fold increase in the abundance of the secondary source, indicating the immune disorders in response to the oxidized aerosols. Mediation analysis demonstrated the necessity of transformation products between atmospheric oxidation capacity and IL-2/IL-8 inhibition. This study provides new information on particulate electrophilic compounds and highlights the role of atmospheric chemistry in specific immune disorders.