Time Variant Exposure Analysis (TVEA): A Measurement Tool for Characterizing Particulate Exposure Determinants in Construction

Abstract

A work sampling-based approach, time variant exposure analysis (TVEA), was developed for assessment of determinants for particulate air contaminants in dynamic construction environments. To use TVEA, the field researcher records observations at fixed intervals to systematically survey over 30 potential determinants that could affect exposure to three types of particulate matter: quartz-containing dusts, diesel exhaust, and a general grouping of “other particles” that includes welding fume and wood dust. Two field studies were conducted to address questions of inter-rater reliability (n = 20) and coding interval appropriateness (n = 21) for the TVEA method. At least substantial inter-rater agreement (kappa > 0.60) was obtained for the TVEA variables related to tool or machine use, process, material, source intensity, and source orientation. Kappa values for source direction (0.22–0.38) and number of sources (0.38–0.60) showed comparatively lower agreement for all particulate types. Observation interval appropriateness was analyzed using linear regression to compare a 5-min observation interval “gold standard” with alternate intervals. Regression statistics indicated that while 30 min is an acceptable interval for exposure assessment, 15 min optimizes precision and practicality by ensuring that 95% of all observations differ less than ten percentage points from the “true” values. TVEA is a useful exposure assessment tool for the dynamic construction environment. It is flexible in that only those determinants that are of interest need be coded and the coding interval can be adjusted to accommodate the level of precision desired.

Keywords:

• construction
• exposure assessment
• particulate matter

ACKNOWLEDGMENTS

Thanks to the contractors, construction workers, and local unions who participated in the sampling, and to the students and staff who assisted in data collection and analysis: Abbas Virji, Nicole Blute, Rebecca Gore, Dana Hanson, and Heather Lyons. Also, thanks to Pam Susi and Jim Platner from CPWR for their assistance and support.

This publication was supported by grant number CCU317202 from the National Institute of Occupational Safety and Health (NIOSH) of the Centers for Disease Control and Prevention in cooperation with the Center to Protect Workers' Rights.

The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of NIOSH.

Notes

^A Quartz (Q), Diesel (D), Other Particles (P).

^B Only present in observation interval dataset.

^C Only present in inter-rater dataset.

^D Traffic indicates the volume of traffic and the distance between the worker and the roadway adjacent to the construction site.

^A Agreement scale based on Landis and Koch (1977) kappa evaluation criteria.

^B Weighted kappa.