Two devices, an occupational carbon monoxide (CO) dosimeter (LOCD), and an indoor air quality (IAQ) passive sampler were developed for use in population-based CO exposure assessment studies. CO exposure is a serious public health problem in the US., causing both morbidity and mortality (lifetime mortality risk approximately 10-4. Sparse data from population-based CO exposure assessments indicate that approximately 10\% of the U.S. population is exposed to CO above the national ambient air quality standard. No CO exposure measurement technology is presently available for affordable population-based CO exposure assessment studies.
The LOCD and IAQ Passive Sampler were tested in the laboratory and field. The palladium-molybdenum based CO sensor was designed into a compact diffusion tube sampler that can be worn. Time-weighted-average (TWA) CO exposure of the device is quantified by a simple spectrophotometric measurement. The LOCD and IAQ Passive Sampler were tested over an exposure range of 40 to 700 ppm-hours and 200 to 4200 ppm-hours, respectively. Both devices were capable of measuring precisely (relative standard deviation \<20\%), with low bias (\<10\%). The LOCD was screened for interferences by temperature, humidity, and organic and inorganic gases. Temperature effects were small in the range of 10{\textdegree}C to 30{\textdegree}C. Humidity effects were low between 20\% and 90\% RH. Ethylene (200 ppm) caused a positive interference and nitric oxide (50 ppm) caused a negative response without the presence of CO but not with CO.
The LOCD was used to monitor personal TWA CO exposures of 154 workshifts in a convention center during heavy use of propane powered forklifts. Performance of the LOCD was compared to an accurate standard method and against the commonly user Dr{\"a}ger CO diffusion tube. Exposure distributions were measured by the LOCD with a precision of about {\textpm}1 ppm. The Dr{\"a}ger tube was found to have a negative bias (20\% at 8-hour TWA of 10 ppm, 40\% below 10 ppm). Only one exposure exceeded the Cal/OSHA PEL of 25 ppm TWA for 8-hours. Workers at the loading docks had the highest 8-hour TWA exposures (50\% \>12.5 ppm). The LOCD is potentially valuable as a device for measurement of occupational CO exposures.
}, year = {1997}, booktitle = {Environmental Health Sciences}, journal = {Environmental Health Sciences}, series = {Environmental Health Sciences}, pages = {200}, month = {09/1997}, address = {Berkeley, California}, language = {eng}, }