[Ventilation in trailers].

There are many possible means of determining exposure ranging from self-reports of physical exposure to measures of muscle activations and estimated spinal loads. In epidemiologic studies, issues of validity make instrumented measures preferable, however issues of cost and practicability tend to force investigators to less costly but less valid and less reliable measures of exposure, such as self-report questionnaires. This paper presents a method by which estimates of exposure from self-report questionnaires, expert observers, work sampling, video analysis and electromyograms can be reported in a common metric, Newtons of force on a tissue, and show, as an example of its application, estimation of spinal compression on auto workers. A common metric allows a flexible approach to selection of measurement methods in occupational settings: no matter which instrument is used the results can be combined to provide an overall picture of exposure. This approach to exposure assessment for the low back allows for comparability across studies and settings.

Automobiles↗

PubMed1997

An analysis of Michigan and California CO remote sensing measurements.

Remote sensing measurements of CO emissions from onroad vehicles were made in California in 1991 and in Michigan in 1992. It was determined that both fleets had a small linear increase in the high emitter frequency (vehicles emitting more than 4% CO) as a function of vehicle age for 1986 and newer model vehicles. Although high emitting vehicles were only a small minority of the fleet, they had a dominant impact on the mean CO and total CO emitted by the fleet. In Michigan, the highest emitting 5% of passenger cars generated 45% of the CO from cars. In California, the highest emitting 5% of passenger cars generated 38% of the CO from cars. There was a high correlation between the mean CO emitted by each model year of vehicle and the frequency of high emitting vehicles within the model year for both the Michigan and California fleets. The frequency of high emitters within any model year had no obvious relation to that model year's certification standards. The high emitter frequencies for vehicles less than nine years old were very similar for the California and Michigan fleets. An increase in the high emitter frequency in the ten-year-old and older Michigan passenger car fleet (relative to the California passenger car fleet), suggests, but does not conclusively demonstrate, that the rate of high emitters in Michigan and California is reduced by the inspection and maintenance (I/M) programs.

Automobiles↗