Reactive Ambient Particles

Abstract

One of the major causative factors for adverse human health outcomes following exposure to ambient airborne particulate matter (PM) is oxidative stress. Thus, it is necessary to examine how particles can induce oxidative stress and since oxidizing species typically react quickly, it then points toward particles that are chemically reactive that are likely to be important as drivers of health effects. Reactive particles can provide oxidants in two ways. There can be exogenous reactive oxygen species (ROS) that are formed through the formation mechanisms of secondary organic aerosol (SOA) and be transported as part of the particle into the respiratory system. Alternatively, particles can include reactive species that can form oxidant in situ (endogenous ROS) that then react with the lung tissues to induce inflammation and stress. This chapter will review the formation chemistry of both exogenous and endogenous ROS and what is known about the potential of ambient PM to induce oxidative stress.