26855604

PMC4741105

Indoor chemistry may be initiated by reactions of ozone (O|), the hydroxyl radical (OH), or the nitrate radical (NO|) with volatile organic compounds (VOC). The principal indoor source of O| is air exchange, while OH and NO| formation are considered as primarily from O| reactions with alkenes and nitrogen dioxide (NO|), respectively. Herein, we used time-averaged models for residences to predict O|, OH, and NO| concentrations and their impacts on conversion of typical residential VOC profiles, within a Monte Carlo framework that varied inputs probabilistically. We accounted for established oxidant sources, as well as explored the importance of two newly realized indoor sources: (|) the photolysis of nitrous acid (HONO) indoors to generate OH and (|) the reaction of stabilized Criegee intermediates (SCI) with NO| to generate NO|. We found total VOC conversion to be dominated by reactions both with O|, which almost solely reacted with d-limonene, | also with OH, which reacted with d-limonene, other terpenes, alcohols, aldehydes, and aromatics. VOC oxidation rates increased with air exchange, outdoor O|, NO| and d-limonene sources, and indoor photolysis rates; and they decreased with O| deposition and nitric oxide (NO) sources. Photolysis was a strong OH formation mechanism for high NO, NO|, and HONO settings, but SCI/NO| reactions weakly generated NO| except for only a few cases.

CDC Public Access

CC999999/Intramural CDC HHS/United States