Total versus inhalable sampler comparison study for the determination of asphalt fume exposures within the road paving industry

Abstract

Exposure to asphalt fumes has a threshold limit value (TLV of 0.5 mg m(-3) (benzene extractable inhalable particulate) as recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). This reflects a recent change (2000) whereby two variables are different from the previous recommendation. First is a 10-fold reduction in quantity from 5 mg m(-3) to 0.5 mg m(-3). Secondly, the new TLV specifies the "inhalable" fraction as compared to what is presumed to be total particulate. To assess the impact of these changes, this study compares the differences between measurements of paving asphalt fume exposure in the field using an "inhalable" instrument versus the historically used 'total' sampler. Particle size is also examined to assist in the understanding of the aerodynamic collection differences as related to asphalt fumes and confounders. Results show that when exposures are limited to asphalt fumes, a 1:1 relationship exists between samplers, showing no statistically significant differences in benzene soluble matter (BSM). This means that for the asphalt fume ACGIH TLV, the 'total' 37-mm sampler is an equivalent method to the "inhalable" method, referred to as IOM (Institute of Occupational Medicine), and should be acceptable for use against the TLV. However, the study found that when confounders (dust or old asphalt millings) are present in the workplace, there can be significant differences between the two samplers' reported exposure. The ratio of IOM/Total was 1.37 for milling asphalt sites, 1.41 for asphalt paving over granular base, and 1.02 for asphalt over asphalt pavements.

A Comparison of Total, Respirable, and Real-Time Airborne Particulate Sampling in Horse Barns

“…In the last decade there has been increased awareness that TP samples do not capture all of airborne particulate mass, (12,13) and there has been increased interest in the Institute of Medicine (IOM) sampler designed to capture larger airborne particles missed by the standard methods of TP sampling. (14) Although we did not include IOM samples in our measurements, it is likely that airborne particulate concentrations measured by IOM sampling would be larger than the TP measurements made in this study.…”

Personal Breathing Zone Exposures among Hot-Mix Asphalt Paving Workers; Preliminary Analysis for Trends and Analysis of Work Practices That Resulted in the Highest Exposure Concentrations

“…Over the time period that these studies were conducted (i.e., 1998-2008), the arithmetic mean HMA paving application temperatures have decreased, supporting claims by industry that application temperatures are being lowered, when possible, as recommended by NIOSH. (2) Averaging the TOM exposure data from the two earlier studies (21,26) (1.32 mg/m 3 ) and comparing the result to our TOM exposure data for when diesel oil was used shows an estimated TOM reduction of 22% and corresponds to an HMA paving application temperature decrease of ~11°C.…”

“…Kriech et al (21) data show TOM = 1.23 mg/m 3 and Kriech et al (26) data show TOM = 1.41 mg/m 3 ; for both studies, the arithmetic mean HMA paving application temperature was 150°C. In the current study, the arithmetic mean data show TOM = 1.03 mg/m 3 at an arithmetic mean HMA paving application temperature of 139°C for diesel oil use.…”

“…(25,26) However, three HMA paving workers had exposures that exceeded this TLV ® during a sampling day when the HMA paving crew used an older paver configured with a diesel-powered screed. These data, shown in Figure 1, are the highest three BSF points for diesel oil use (concentrations shown in Supplemental Table 2).…”

Field Sampling Investigations Within the Road Paving Industry

“…(2) As a non-size-specific sampler (collection of matter with no specific considerations dedicated to the inhalable fraction), the 37-mm cassette is frequently referred to as a "total" aerosol sampler. (3) In 1998, the National Institute for Occupational Safety and Health (NIOSH) published a specific method for determining asphalt fumes as the benzene-soluble fraction (BSF) and total airborne particulates. (4) Owing to its convenience, NIOSH specified the 37-mm cassette to capture the particulates.…”