Measurements of quinones in fine particulate matter

Inhalation of fine particulate matter (PM) has been shown to be harmful to human health and well-being. One of the main mechanisms of particle toxicity in the lungs is the generation of reactive oxygen species (ROS) which contributes to respiratory diseases such as asthma and lung cancer. Specific chemical constituents of PM have been implicated in the conversion of molecular oxygen to the harmful ROS but the extent of contribution by these chemical species is not well understood. Quinones are a class of organic molecules found in the complex composition of fine PM that have been shown to undergo a potentially indefinite catalytic process generating ROS in the lungs. Fine particles were collected for two weeks in winter of 2013 in Fresno California, analyzed for the presence of specific quinones, and compared with measurements of ROS formation. Four quinones were identified using gas chromatography mass spectrometry (GCMS): 9,10-phenanthraquinone, 9,10-anthraquinone, 1,4-napthoquinone, and 1,2-naphthoquinone. Comparison with ROS generated by particles in a cell-free, surrogate lung fluid show some contribution of quinones to the production of ROS but the contributions are shown to be minimal.