Validity of empirical models of exposure in asphalt paving.
OBJECTIVE
To investigate the validity of empirical models of exposure to bitumen fume and benzo(a)pyrene, developed for a historical cohort study of asphalt paving in Western Europe.


METHODS
Validity was evaluated using data from the USA, Italy, and Germany not used to develop the original models. Correlation between observed and predicted exposures was examined. Bias and precision were estimated.


RESULTS
Models were imprecise. Furthermore, predicted bitumen fume exposures tended to be lower (-70%) than concentrations found during paving in the USA. This apparent bias might be attributed to differences between Western European and USA paving practices. Evaluation of the validity of the benzo(a)pyrene exposure model revealed a similar to expected effect of re-paving and a larger than expected effect of tar use. Overall, benzo(a)pyrene models underestimated exposures by 51%.


CONCLUSIONS
Possible bias as a result of underestimation of the impact of coal tar on benzo(a)pyrene exposure levels must be explored in sensitivity analysis of the exposure-response relation. Validation of the models, albeit limited, increased our confidence in their applicability to exposure assessment in the historical cohort study of cancer risk among asphalt workers.
Division of Environmental and Occupational Health, Institute for Risk Assessment Sciences, Utrecht University, PO Box 80176, 3508 TD Utrecht, Netherlands.
I
I
Burstyn
P
P
Boffetta
G A
GA
Burr
A
A
Cenni
U
U
Knecht
G
G
Sciarra
H
H
Kromhout
D000395:Air Pollutants, Occupational; D001564:Benzo(a)pyrene; D015982:Bias; D015331:Cohort Studies; D003252:Construction Materials; D005060:Europe; D006801:Humans; D006838:Hydrocarbons; D008962:Models, Theoretical; D016273:Occupational Exposure / Q000032:analysis*; D014481:United States; D014835:Volatilization
D000395:Air Pollutants, Occupational; D006838:Hydrocarbons; D001564:Benzo(a)pyrene; C006647:asphalt