Peroxides and macrophages in the toxicity of fine particulate matter in rats.

Epidemiologists have observed a positive association between human morbidity and mortality and the atmospheric concentrations of fine particulate matter (PM), but the mechanisms underlying the toxic effects of PM have not been elucidated. Various components of ambient PM have been implicated in toxicity (including ultrafine particles, transition metals, organics and oxidants). Our research focused on hydrogen peroxide (H2O2).

Indoor hydrogen peroxide derived from ozone/d-limonene reactions.

In this pilot study, performed in an office manipulated to resemble an environment with a strong indoor ozone source or a significant influx of outdoor air during a smog event, reactions between ozone and d-limonene produced hydroperoxides. Hydrogen peroxide (H202) presumably constituted the majority of the measured hydroperoxides, although a small amount of organic hydroperoxides (ROOH) may have contributed to the signal. Total hydroperoxides were 1.