title: Generation of hydroxyl radicals from ambient fine particles in a surrogate lung fluid solution.
abstract: While it has been hypothesized that the adverse health effects associated with ambient particulate matter (PM) are due to production of hydroxyl radical (*OH), few studies have quantified *OH production from PM. Here we report the amounts of *OH produced from ambient fine particles (PM2.5) collected in northern California and extracted in a cell-free surrogate lung fluid (SLF). On average, the extracted particles produced 470 nmol *OH mg(-1)-PM2.5 during our 15-month collection period. There was a clear seasonal pattern in the efficiency with which particles generated *OH, with highest production during spring and summer and lowest during winter. In addition, nighttime PM was typically more efficient than daytime PM at generating *OH. Transition metals played the dominant role in *OH production: on average (+/-sigma), the addition of desferoxamine (a chelator that prevents metals from forming *OH) to the SLF removed (90 +/- 5) % of *OH generation. Furthermore, based on the concentrations of Fe in the PM2.5 SLF extracts, and the measured yield of *OH as a function of Fe concentration, dissolved iron can account for the majority of *OH produced in most of our PM2.5 extracts.
authors.affiliation: Graduate Group in Agricultural and Environmental Chemistry, Department of Land, Air and Water Resources, University of California-Davis, 1 Shields Avenue, Davis, California 95616, USA.
authors.forename: Edgar
authors.initials: E
authors.lastname: Vidrio
authors.forename: Chin H
authors.initials: CH
authors.lastname: Phuah
authors.forename: Ann M
authors.initials: AM
authors.lastname: Dillner
authors.forename: Cort
authors.initials: C
authors.lastname: Anastasio
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D001826:Body Fluids / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D008168:Lung / Q000737:chemistry*; D010316:Particle Size; D012996:Solutions
chemical_list: D000393:Air Pollutants; D012996:Solutions; D017665:Hydroxyl Radical