Ozone is recognized as one of the most dangerous
irritants to eyes, throat, lungs and etc .. Chamber studies
consistently have demonstrated adverse effects of ozone on
human lung function. The results of epidemiological studies,
however, have been controversial, partly because there are
many factors that affect human lung function. Thus it has been
difficult to control confounding in epidemiological studies.
Among these factors, retention and ventilation are two of the
more important because of their strong influence on ozone's
physiologically effective dose. This study used a computer
simulation model, utilizing data from the "children's Camp
Study", to analyze the effects of retention factors and
ventilation on ozone's physiologically effective dose. The
results of the simulations indicated appreciable improvement
in the estimated exposure to ozone when inhaled ozone exposure
(effective dose) was included in the model. These results were
consistent with the study's a priori- hypothesis (that
incorporating retention and ventilation factors into the model
would improve the estimated exposure to ozone) primarily
because of the greater precision and reduction in bias
associated with the use of heart rate data that were child-and
hour-specific. The study identified three simulation data sets
for which the ozone dose model yielded a more significant
coefficient than did the average ozone concentration model.
Using the t-statistic, the three models were seen to follow
the expected pattern, with statistically significant
differences between the R² values (the coefficient of
variation changed from 45.4 to 11.0 when the error term was
0. 01). The results of the analyses support the hypothesis that
ventilation and retention factors can be used to increase the
precision of ozone exposure measurement and reduce exposure
assessment errors significantly, thereby sharpening the power
of studies evaluating ozone's acute health effects. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37217 |
| Date | 16 January 1992 |
| Creators | Yu, Xianhong |
| Contributors | Rossignol, Annette |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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