Ozone Reactions with Squalene: Particle Formation and Chemical Identification
Ground-level ozone penetration indoors is the dominant and controlling source of ozone indoors, resulting in continuous ozone exposures to people. One substrate that ozone reacts with is squalene, an unsaturated skin lipid. Squalene-ozone reaction byproducts include particulate-phase products that may cause respiratory and ocular irritation, which is particularly concerning to vulnerable populations such as asthmatics and the elderly. The goal of my research is to identify and characterize the ozone-squalene reaction byproducts that may degrade indoor air quality and document their potential human exposures. My proposed work will better characterize the factors (i.e. relative humidity, ozone concentration, seed particle composition, and squalene loading) that affect particle formation from squalene-ozone reactions. I will also determine the chemical composition of the particles formed by collecting them onto Teflon filters and subsequently analyzing them through derivatization followed by gas chromatography mass spectrometry or directly by liquid chromatography mass spectrometry. My preliminarily results have identified a number of carbonyls formed. Particle number analysis will be determined with a condensation particle counter to investigate the previously mentioned factors influencing particle formation. Three sample types will be analyzed: 1) particles from squalene-ozone reactions on glass plates, 2) particles produced and skin wipes from exposing people to ozone in a controlled exposure facility and 3) particles collected from homes of elderly persons residing in New Jersey and Georgia during the ozone season. Since squalene is found on the surface of hair, clothing, and in house dust, in addition to skin, the squalene-ozone reaction is important in reducing ozone levels in homes but results in the generation of reaction products that people breathe in. The average human spends approximately 90% of their time indoors, so exposures to components found within indoor air are of concern. These reaction products in which people are exposed to may contribute to health issues attributed to ambient ozone.
This project resulted in the following publication:
Breann Coffaro and Clifford P.Weisel, (2022). The effect of environmental parameters on squalene-ozone particle formation, Atmospheric Environment, 289 (15): 119295. https://doi.org/10.1016/j.atmosenv.2022.119295
Ground-level ozone penetration indoors is the dominant and controlling source of ozone indoors, resulting in continuous ozone exposures to people. One substrate that ozone reacts with is squalene, an unsaturated skin lipid. Squalene-ozone reaction byproducts include particulate-phase products that may cause respiratory and ocular irritation, which is particularly concerning to vulnerable populations such as asthmatics and the elderly. The goal of my research is to identify and characterize the ozone-squalene reaction byproducts that may degrade indoor air quality and document their potential human exposures. My proposed work will better characterize the factors (i.e. relative humidity, ozone concentration, seed particle composition, and squalene loading) that affect particle formation from squalene-ozone reactions. I will also determine the chemical composition of the particles formed by collecting them onto Teflon filters and subsequently analyzing them through derivatization followed by gas chromatography mass spectrometry or directly by liquid chromatography mass spectrometry. My preliminarily results have identified a number of carbonyls formed. Particle number analysis will be determined with a condensation particle counter to investigate the previously mentioned factors influencing particle formation. Three sample types will be analyzed: 1) particles from squalene-ozone reactions on glass plates, 2) particles produced and skin wipes from exposing people to ozone in a controlled exposure facility and 3) particles collected from homes of elderly persons residing in New Jersey and Georgia during the ozone season. Since squalene is found on the surface of hair, clothing, and in house dust, in addition to skin, the squalene-ozone reaction is important in reducing ozone levels in homes but results in the generation of reaction products that people breathe in. The average human spends approximately 90% of their time indoors, so exposures to components found within indoor air are of concern. These reaction products in which people are exposed to may contribute to health issues attributed to ambient ozone.
This project resulted in the following publication:
Breann Coffaro and Clifford P.Weisel, (2022). The effect of environmental parameters on squalene-ozone particle formation, Atmospheric Environment, 289 (15): 119295. https://doi.org/10.1016/j.atmosenv.2022.119295