ozone

The purpose of this paper is to present an experimental setup developed to characterizereactions between ozone and building products and document their potential impact on indoorair quality. Preliminary experiments were conducted on four building products: two carpets, agypsum board and a pine wood board. These preliminary experiments clearly indicate thatozone is significantly removed in contact with the four selected products. Measured ozoneremoval were around 65% for the two carpets, 70% for the gypsum board and 75% for thepine wood board.

Indoor chemistry is receiving attention due to the possible health effects of products ofreactions between indoor pollutants, and the potential for such products to contribute to indoorparticulate matter (PM). Much of the focus with respect to indoor chemistry has been onterpene/ozone reaction products, since terpenes are ubiquitous indoors, ozone readilyinfiltrates from outdoors, and the reaction rates are comparable to typical air exchange rates inmany indoor settings. Several studies have documented particle formation from reactionsbetween ozone and a-pinene or d-limonene.

The purpose of this paper is to document the potential impact on indoor air quality of outdoorozone during photochemical pollution episodes. A preliminary one-day experiment wasconducted during summer 2002 in a room of the CSTB experimental house MARIA. Ozone,VOC and aldehyde concentrations were monitored outdoors and indoors from 8 a.m. to 8 p.m.Outdoor ozone hourly mean concentrations increased from 30 to 100 g/m3 during the day.The indoor to outdoor ratio ranged from 0.10 to 0.25, indicating possible ozone-inducedreactions occurring indoors.

Usually only primary emissions from building products are measured. That study takes into account potential secondary emissions due to oxidation with ozone. In the long run secondary emissions may influence the perceived air quality.The aim of that study was to investigate if the interaction between ozone and selected building products induces changes in emissions.

The objective of this study has been to clarify to what extent ozone (O3) and O3 /limonene in interaction with surface materials has an impact on the indoor air quality in typical low-polluting offices at realistic outdoor air change rates. Three similar offices furnished with the same materials and ventilated with charcoal filtered outdoor air were used in the study. Eight environmental conditions with different realistic combinations of air change rate, O3 and limonene levels were studied.

Three offices ventilated with charcoal filtered outdoor air were investigated with different air change rates, ozone level and limonene, using the perception of a sensory panel. Results confirm that ventilation is necessary for ensuring good indoor quality even in low-polluting offices.

Measured ozone decay rates were found to be significantly correlated with house type and the number of bedrooms for a monitoring project of 43 California homes. The observed decay rates were higher in multiple-family homes and homes with fewer than three bedrooms. Homes with higher surface-area-to-volume ratios had higher decay rates.

In order to determine whether high outdoor ozone concentrations are transferred to the indoor climate of museums, a monitoring project was carried out on eleven museums, art galleries, historical houses and a museum library for 38 days over the summers of 1984 and 1985. The differences in indoor ozone levels between the buildings could be explained by differences in building and ventilation system design, and this was verified by a mathematical model. Peak indoor ozone levels were highest in building with no air conditioning but a high rate of air exchange with the outdoors.

The emission rate of VOCs and aldehydes from materials typically found in ventilation ducts was measured. It was found to be low for some duct liners, but high for duct sealing caulk and a neoprene gasket - in fact approaching the odour threshold. Exposure to ozone was found to increase the emission rate of aldehydes from a duct liner, duct sealing caulk and neoprene gasket. When exposed to ozone, the removal efficiency for a lined duct diminished to less than 4% over 10 days. It was much lower for an unlined duct.