Predicting changes in PM exposure over time at U.S. trucking terminals using structural equation modeling techniques.
This study analyzes the temporal variability of occupational and environmental exposures to fine particulate matter in the U.S. trucking industry and tests the predictive ability of a novel multilayer statistical approach to occupational exposure modeling using structural equation modeling (SEM) techniques. For these purposes, elemental carbon mass in PM<1 microm at six U.S. trucking terminals were measured twice during the same season up to 2 years apart, observing concentrations in the indoor loading dock (median EC: period 1 = 0.65 microg/m(3); period 2 = 0.94 microg/m(3)) and outdoor background location (median EC: period 1 = 0.46 microg/m(3); period 2 = 0.67 microg/m(3)), as well as in the truck cabs of local drivers while on the road (median EC: period 1 = 1.09 microg/m(3); period 2 = 1.07 microg/m(3)). There was a general trend toward higher exposures during the second sampling trips; however, these differences were statistically significant in only a few cases and were largely attributable to changes in weather patterns (wind speed, precipitation, etc.). Once accounting for systematic prediction errors in background concentrations, the SEM approach provided a strong fit for work-related exposures in this occupational setting.
Department of Urban and Environmental Policy and Planning, Tufts University, Medford, Massachusetts 02155, USA. mary.davis@tufts.edu
Mary E
ME
Davis
Francine
F
Laden
Jaime E
JE
Hart
Eric
E
Garshick
Andrew
A
Blicharz
Thomas J
TJ
Smith
D000395:Air Pollutants, Occupational / Q000032:analysis*; D001334:Automobile Driving; D004781:Environmental Exposure / Q000032:analysis; D004784:Environmental Monitoring; D005544:Forecasting / Q000379:methods*; D008962:Models, Theoretical; D018986:Motor Vehicles; D016273:Occupational Exposure / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D013997:Time Factors; D014481:United States
D000395:Air Pollutants, Occupational; D052638:Particulate Matter