US EPA

35793 

Journal Article 

Hydroxyl radicals in indoor environments 

Sarwar, G; Corsi, R; Kumura, Y; Allen, D; Weschler, CJ 

2002 

1 

Atmospheric Environment
ISSN: 1352-2310
EISSN: 1873-2844 

36 

24 

3973-3988 

English 

10.1016/S1352-2310(02)00278-9 

WOS:000178355800010 

#Indoor hydroxyl radical concentrations were estimated using a new indoor air quality model which employs the SAPRC-99 atmospheric chemistry model to simulate indoor homogenous reactions. Model results indicate that typical indoor hydroxyl radical concentrations are lower than typical outdoor summertime urban hydroxyl radical levels of 5-10Î106 molecules cm-3; however, indoor levels can be similar to or greater than typical nighttime outdoor hydroxyl radical levels of approximately 5Î104 molecules cm-3. Effects of selected parameters on indoor hydroxyl radical concentrations are presented herein. Indoor hydroxyl radical concentrations are predicted to increase non-linearly with increasing outdoor ozone concentrations, indoor alkene emission rates, and air exchange rates. Indoor hydroxyl radical concentrations decrease with increasing outdoor nitric oxide concentrations. Indoor temperature and indoor light intensity have moderate impacts on indoor hydroxyl radical concentrations. Outdoor hydroxyl radical concentrations, outdoor nitrate (NO3.) radical concentrations, outdoor hydroperoxy radical concentrations, and hydroxyl radical removal by indoor surfaces are predicted to have no appreciable impact on indoor hydroxyl radical concentrations. Production of hydroxyl radicals in indoor environments appears to be controlled primarily by reactions of alkenes with ozone, and nitric oxide with hydroperoxy radical. Estimated indoor hydroxyl radical levels may potentially affect indoor air quality. Two examples are presented in which reactions of d-limonene and "alpha"-pinene with indoor hydroxyl radicals produce aldehydes, which may be of greater concern than the original compounds. 

indoor air quality; chemistry; ozone; hydroxyl radicals; aldehydes