The Harvard Southern California Chronic Ozone Exposure Study: assessing ozone exposure of grade-school-age children in two Southern California communities.

Abstract

The Harvard Southern California Chronic Ozone Exposure Study measured personal exposure to, and indoor and outdoor ozone concentrations of, approximately 200 elementary school chlidren 6-12 years of age for 12 months (une 1995(une -May 1996. We selected two Southern California communities, Upland and several towns located in the San Bernardino mountains, because certain characteristics of those communities were believed to affect personal exposures.On 6 consecutive days during each study month, participant homes were monitored for indoor and outdoor ozone concentrations, and participating children wore a small passive ozone sampler to measure personal exposure. During each sampling period, the children recorded time-location-activity information in a diary. Ambient ozone concentration data were obtained from air quality monitoring stations in the study areas. We present ozone concentration data for the ozone season (une-September 1995 and May 1996) and the nonozone season (October 1995-April 1996. During the ozone season, outdoor and indoor concentrations and personal exposure averaged 48.2, 11.8, and 18.8 ppb in Upland and 60.1, 21.4, and 25.4

Commuters’ Personal Exposure to Ambient and Indoor Ozone in Athens, Greece

“…The comparison of personal ozone levels to those documented from other studies is constrained by a number of factors: method and uncertainty of sampling, different climatic conditions, season and period of sampling, participants' activity pattern, etc. Nevertheless, the ratios of personal to residential-outdoor (0.14 ± 0.09) and personal to office-outdoor (0.1 ± 0.06) concentrations were similar to those found for Athens and Thessaloniki cities by Grivas et al [23], or other cities worldwide [22,43,44] during fall. As Grivas et al [23] underlined, the low ratio value reveals the large discrepancy between the two exposure metrics (personal versus ambient air) and thus the protective role of the indoor environment, due to the lack of indoor sources of ozone and the increased times spent indoors.…”

“…However, as these measurements do not take into account the existence of a personal cloud of each individual, they usually result in poor correlations of personal exposure with ambient concentrations [14][15][16][17][18]. These limitations were overtaken by the development of light-weight passive ozone samplers [19] for the assessment of personal exposure to O 3 , which have been used to a large extent since then [3,5,17,18,[20][21][22][23][24][25], and still comprise a reliable [26] and cost-effective method.…”

A national fine spatial scale land-use regression model for ozone

“…At each end of the cylinder a nitrite based filter is placed between two stainless steel screens and sealed with a cap with holes where diffusion can take place. Ogawa samplers for ozone have been used before to map ozone concentrations (Liu and Rossini, 1996;Koutrakis et al, 1993;Geyh et al, 2000;Lozano et al, 2009;Gibson et al, 2009) and shown to agree well with continuous ozone monitors. The principle of the method is that ozone oxidizes nitrite to nitrate.…”

“…The sampling rate for the Ogawa passive sampler given in the Ogawa protocol was used as a constant of 21.8 mL min À 1 (Ogawa, 2001). The same sampling rate has been used different articles using the Ogawa passive sampler (Geyh et al, 2000;Gibson et al, 2009;Gerboles et al, 2006;Salem et al, 2009). The collection rate of passive samplers was shown not to be affected by temperature and humidity (Geyh et al, 2000;Gibson et al, 2009).…”

Comparison between Personal and Individual Exposure to Urban Air Pollutants

“…Most of the studies about the comparison between O 3 personal exposure indicated a limited correspondence with the concentrations measured at a fixed site, both indoors and outdoors (Geyh et al 2000;Lee et al 2004;Linn et al 1996;Sarnat et al 2005), because fixed site measurements do not take into account the spatial variability of O 3 , indoor/outdoor differences (high reactivity and low infiltration rates) and emission sources related to specific activities. Predictive models based on the weighted contribution of different activities could explain 40% of the personal exposure variability, up to 76% for subjects who spend most of their time indoors (Liu et al 1993).…”