This study was undertaken to determine if the ventilatory capacity of children is affected by hourly concentrations of ozone inhaled during their daily activity. Over a 3-wk period (June-July 1987) children who were attending a summer camp in the San Bernardino mountains of California performed spirometry up to three times per day during their stay at the camp. A total of 43 children were tested a total of 461 times. Ozone, oxides of nitrogen, sulfur dioxide, temperature, and relative humidity were measured continuously. Daily average measurements of total suspended particulate and the PM10 particulate fraction (less than or equal to 10 microns) were also made. Hourly ozone concentrations at the time of testing varied between 20 and 245 ppb. Regressions of each individual's FEV1 and FVC supported the view that high ozone levels reduced these lung function parameters. The average regression coefficient for FEV1 on ozone was -0.39 ml/ppb (SEM = 0.12) and for FVC -0.44 ml/ppb (SEM = 0.15), both of which were significantly different from zero. Statistical allowance for temperature and humidity increased the magnitude of these slopes. Nitrogen dioxide never exceeded 40 ppb during the time of testing and averaged 13 ppb. Sulfur dioxide's highest measurement was 8 ppb and often was at the limit of detection. Neither NO2 nor SO2 was considered in the statistical modeling. Data were divided based on whether each subject had been exposed to levels of ozone in excess of the National Ambient Air Quality Standard (NAAQS) during the several hours previous to being tested. Exposures exceeding the NAAQS indicated a significant negative relationship between ozone and FEV1, FVC, and PEFR. Data for nonexceedance periods did not indicate this negative relationship for any of the three lung function parameters, but it could not be determined if this was due to an absence of an ozone effect or to a combination of the increased variability and decreased size of this data subset. These data indicate that lung function changes on a daily basis relate in a negative fashion to ambient ozone levels. The magnitude of the changes are small and are reversed as ambient ozone decreases.
Abstract. Dimensional management is a form of quality assurance for the manufacture of mechanical structures, such as vehicle bodies. Establishing and maintaining dimensional control is a process of adjusting complex machinery for environmental and material changes to manufacture product to specifications within very small tolerances. It involves constant monitoring of the process as well as responding to crises. A good deal of undocumented "folk wisdom" is built up by the dimensional management teams on how to diagnosis and cure problems, but this knowledge tends to be lost over time (people can't remember, people move on) and is rarely shared from shop to shop. Our project involves establishing a case-based diagnostic system for dimensionalmanagement problems, which can also serve as a system for systematically documenting solved dimensional-control problems. It is intended that this documentation should be meaningful over time and be shareable between plants. The project includes defining a workable case structure and matching ontology, especially to establish the context and generic language to accomplish this. A prototype system has been launched in a vehicle assembly plant.
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