Ozone indoors

Knudsen, H.N., Nielsen, P.A., Clausen, P.A., Wilkins, C.K. and Wolkoff, P. (2003) Sensory evaluation of emissions from selected building products exposed to ozone. Indoor Air, 13 (3), 223-31. 

Deals with issues that affect the quality of our air and protection from exposure to harmful radiation. OAR de >el-ops national programs, technical policies, and regulations for controlling air pollution and radiation exposure. Areas of concern to OAR include indoor and outdoor air quality, stationaiy and mobile sources of air pollution, radon, acid rain, stratospheric ozone depletion, radiation protection, and pollution prevention. 

This review begins with a summary of the sources of monitoring data operated primarily by public agencies. The spatial and temporal patterns of oxidant concentrations are then discussed—urban versus rural and indoor versus outdoor relationships, diurnal and seasonal patterns, and long-term trends. The chapter includes brief discussions of photochemical oxidants other than ozone and of data quality and concludes with a set of recommendations for guidelines in future monitoring of atmospheric concentrations of ozone and other photochemical oxidants. 

The use of ozonizers for deodorizing indoor air has been discussed and evaluated with respect to potential health hazards. In a normal 40-m room, an ozone concentration of 0.1 ppm is established after 3.5 h of operation of one of these devices. Evidence on health effects was cited to support the conclusion that inhalation of the quantities of ozone produced by these air conditioners should be avoided and that certainly no beneficial effects should be attributed to ozone inhalation. 

Sabersky, R. H., D. A. Sinema, and F. H. Shair. Concentrations, decay rates, and removal of ozone and their relation to establishing clean indoor air. Environ. Sci. Technol. 7 347-353, 1973. 

Enviromnent and health-related problems Bio varnishes , i.e. varnishes based on natural, renewable raw materials, were developed as close-to-nature alternatives (substitutes) i.a. as a reaction to the so-called German wood preservative scandal and indoor pollution due to chemical solvents. Nevertheless, they have until now had a relatively high content of volatile bio-organic solvents, which may cause irritations, allergic and neurotoxic reactions, and contribute to the formation of tropospheric ozone. 

Ozone (O3) is a powerful oxidizing agent. It is found naturally in the atmosphere by the action of electrical storms. The major indoor source of ozone is from electrical equipment and electrostatic air cleaners. The indoor ozone concentration is determined by ventilation. It depends on the room volume, the number of air changes in the room, room temperature, materials, and the nature of surfaces in the room. Ozone is irritating to the eyes and all mucous membranes. Pulmonary edema may occur after exposure has ceased [32,33]. 

Any increase in ultraviolet radiation will exacerbate the danger to herbivores. Ozone depletion by 25% leads to an increase of 50% in ultraviolet B over ambient levels (El-Sayed, 1988). Will livestock be drastically affected if levels rise more in the future Will animals be able to shift to nocturnal activity If not, will large portions of the vegetation be rendered useless for domestic stock and wild species or will animals have to be fed indoors Will humans be affected ... 

Monn C Exposure assessment of air pollutants A review on spatial heterogeneity and indoor/outdoor/personal exposure to suspended particulate matter, nitrogen dioxide and ozone. Atmos Environ 35 1, 2001... 

Industrial activity has polluted the outdoor air with a number of chemicals known to be hazardous to human health. These include a variety of gases, such as carbon monoxide, ozone, and the oxides of sulfur and nitrogen. Unacceptable levels of air pollutants can occur indoors as well. While some of these pollutants may be the same as for the outdoor air, they also include biological... 

Table 15.1 summarizes the major species of concern for indoor air pollution and some of their sources (Su, 1996). We focus in this chapter primarily on those species common to indoor and outdoor air environments, including oxides of nitrogen, volatile organic compounds (VOC), CO, ozone, the OH radical, S02, and particles. In addition, a brief discussion of radon is included since this has been one of the major foci of concern in the past with respect to indoor air pollution. 

In the indoor environment in cars, ozone levels tend to be significantly less than in the surrounding area. For example, Chan et al. (1991b) report that in-vehicle 03 concentrations during commutes in Raleigh, North Carolina, were only about 20% of those measured in the local area at a fixed station. There are several contributing factors to these low concentrations. One is that NO concentrations are higher near roadways, so that 03 is titrated to N02 by its rapid reaction with NO. A second is that 03 can decompose... 

As discussed in detail throughout this book, there is rich and complex chemistry involving volatile organic compounds (VOCs), oxides of nitrogen, and ozone in ambient air. One might therefore anticipate similar chemistry in indoor air environments, and although there are far fewer studies, this does indeed appear to be the case. Weschler and Shields (1997b) and Wolkoff et al. (1997, 1999) review VOC-NOx chemistry that could potentially be important in indoor air enviro-ments and the implications for human exposures. 

However, as discussed by Reiss et al. (1995a), separating the contribution of ozone reactions from other factors such as temperature and relative humidity, which also affect direct emissions, is difficult. For example, while the production rate of oxygenated organics is correlated with the ozone removal rate, the latter is also correlated with temperature. As a result, both reaction and increased direct emission rates due to higher temperatures may be contributing to these enhanced indoor levels. 

Ozone can also react with components found in air ducts. For example, Morrison et al. (1998) reported that the sealant and neoprene gaskets used in the ducts emitted VOCs into the airstream, but at relatively low levels compared to the typical concentrations found indoors. However, reaction with 03 led to increased emissions of aldehydes, particularly the C5-C10 aldehydes. 

As discussed in Chapter 9.C.2, some of the larger alkenes such as terpenes form particles containing low-volatility organics on oxidation with ozone. Hence particle formation might be expected indoors in the presence of such compounds, and indeed this has been observed (Weschler and Shields, 1999). 

Druzik, J. R., M. S. Adams, C. Tiller, and G. R. Cass, The Measurement and Model Predictions of Indoor Ozone Concentrations in Museums, Atmos. Environ., 24A, 1813-1823 (1990). 

Morrison, G. C., W. W. Nazaroff, J. Alejandro Cano-Ruiz, A. T. Hodgson, and M. P. Modera, Indoor Air Quality Impacts of Ventilation Ducts Ozone Removal and Emissions of Volatile Organic Compounds, J. Air Waste Manage. Assoc., 48, 941-952 (1998). 

Reiss, R., P. B. Ryan, and P. Koutrakis, Modeling Ozone Deposition onto Indoor Residential Surfaces, Environ. Sci. Technol., 28, 504-513 (1994). 

Romieu, I., M. C. Lugo, S. Colome, A. M. Garcia, M. H. Avila, A. Geyh, S. R. Velasco, and E. P. Rendon, Evaluation of Indoor Ozone Concentration and Predictors of Indoor-Outdoor Ratio in Mexico City, J. Air Waste Manage. Assoc., 48, 327-335 (1998). 

Weschler, C. J., M. Brauer, and P. Koutrakis, Indoor Ozone and Nitrogen Dioxide A Potential Pathway to the Generation of Nitrate Radicals, Dinitrogen Pentaoxide, and Nitric Acid Indoors, Environ. Sci. TechnoL, 26, 179-184 (1992a). 

Weschler, C. J., and H. C. Shields, Indoor Ozone/Terpene Reactions as a Source of Indoor Particles, Atmos. Environ., 33, 2307-2318 (1999). 

Diazinon has a finite vapor pressure (see Chapter 3) and thus will be present in the air. A method for diazinon in air has been reported that is based on the use of polyurethane foam (PUF) to adsorb the pesticide from the air as the air is pulled through the PUF (Hsu et al. 1988). The PUF is then Soxhlet-extracted and the extract volume reduced prior to capillary GC/MS analysis. An LOD of 55 ng/m3 (5.5 m3 sample) and recovery of 73% were reported. Another study was described in which the diazinon levels in indoor air were monitored following periodic application of the pesticide for insect control (Williams et al. 1987). In this method, air is pulled through a commercially available adsorbent tube to concentrate diazinon. The tube is then extracted with acetone prior to GC/NPD analysis. No data were provided for the LOD, but recoveries in excess of 90% were reported at the 0.1 and 1 pg/m3 levels. This paper also indicated that diazinon can be converted to diazoxon by ozone and NOx in the air during the sampling process. 

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