AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
The Concentration of Reactive Oxygen Species in a Sample of Houses in Austin, Texas
SHAHANA KHURSHID, Jeffrey Siegel, Kerry Kinney, The University of Texas at Austin
Abstract Number: 393 Working Group: Indoor Aerosols
Abstract Reactive oxygen species (ROS) are an important class of secondary air pollutants which include hydroperoxides, organic peroxides, hypochlorite ions, and alkyl peroxyl radicals. High levels of ROS in the body can induce cell injury and cause a variety of deleterious health effects. In outdoor air, ROS is mainly generated from photochemical reactions in polluted air containing VOCs and NO$_x. In indoor environments, reactions between ozone and unsaturated organic compounds may be an important additional source of ROS. While ROS can exist in both gas and particulate phases, particulate ROS (especially particles smaller than 2.5 micrometers) can penetrate deep into the lungs. In this research, PM$_(2.5) particles were collected on Teflon filters inside and outside single-family residences in Austin, Texas and ROS was assessed with a fluorescent reagent. The background fluorescence produced by nine different kinds of filters (by Pall, SKC, and Whatman) was assessed and Pall PTFE filters on a polypropylene support were selected for use in the assay because of their low background fluorescence and structural integrity. The average concentration of ROS inside the sample of houses was found to be 1.7 times higher than the average outdoor ROS concentration (3.03 nanomoles H$_2O$_2/m$^3 as compared to 1.78 nanomoles H$_2O$_2/m$^3). The indoor concentration of ROS was a weak function of the outdoor ROS concentration, building age and building size. Additionally, the outdoor concentration of ROS was found to be higher near roadways. The outdoor concentrations agree with other studies which have reported outdoor ROS levels in the range 0.54-5.71 nanomoles/m$^3. This study provides insight into the indoor to outdoor ratio of particulate ROS and is one of the first studies to assess ROS in indoor environments, especially houses. A better understanding of accurate levels of ROS in the places we occupy is essential to establish healthy living environments.