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

Abstract

An exposure assessment of hot-mix asphalt (HMA) paving workers was conducted to determine which of four exposure scenarios impacted worker exposure and dose. Goals of this report are to present the personal-breathing zone (PBZ) data, discuss the impact of substituting the releasing/ cleaning agent, and discuss work practices that resulted in the highest exposure concentration for each analyte.One-hundred-seven PBZ samples were collected from HMA paving workers on days when diesel oil was used as a releasing/cleaning agent. An additional 36 PBZ samples were collected on days when B-100 (100% biodiesel, containing no petroleum-derived products) was used as a substitute releasing/cleaning agent. Twenty-four PBZ samples were collected from a reference group of concrete workers, who also worked in outdoor construction but had no exposure to asphalt emissions. Background and field blank samples were also collected daily. Total particulates and the benzene soluble fraction were determined gravimetrically. Total organic matter was determined using gas chromatography (GC) with flame ionization detection and provided qualitative information about other exposure sources contributing to worker exposure besides Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript asphalt emissions. Thirty-three individual polycyclic aromatic compounds (PACs) were determined using GC with time-offlight mass spectrometry; results were presented as either the concentration of an individual PAC or a summation of the individual PACs containing either 2-to 3-rings or 4-to 6-rings. Samples were also screened for PACs containing 4-to 6-rings using fluorescence spectroscopy.Arithmetic means, medians, and box plots of the PBZ data were used to evaluate trends in the data. Box plots illustrating the diesel oil results were more variable than the B-100. Also, the highest diesel oil results were much higher in concentration than the highest B-100 results. An analysis of the highest exposure results and field notes revealed a probable association between these exposures and the use of diesel oil, use of a diesel-powered screed, elevated HMA paving application temperatures, lubricating and working on broken-down equipment, and operation of a broom machine.

Occupational Exposure during Asphalt Paving—Comparison of Hot and Warm Mix Asphalt in Field Experiments

“…OC measured during paving may originate from different sources, e.g. pollen, the asphalt itself, diesel exhaust from passing traffic (traffic was allowed to pass in the open lane during paving), the paving machines, or other local sources ( Burstyn et al , 2002 ; Osborn et al , 2013 ). EC often originates from diesel engines ( Shah et al , 2004 ).…”

“…Levels of airborne contaminants including respirable particulate matter (PM), total PM, polycyclic aromatic hydrocarbons (PAH), and oil mist and vapor have been measured during asphalt paving ( Burstyn et al , 2002 ; Heikkila et al, 2002 ; Elihn et al , 2008 ; Cavallari et al , 2012 ; Osborn et al , 2013 ; Nilsson et al , 2018 ). However, few studies have investigated airborne contaminants generated during paving with asphalt at different temperatures.…”

Assessing cancer hazards of bitumen emissions – a case study for complex petroleum substances

“…Warm-mix asphalts are applied at temperatures typically 10-40 C lower than conventional rolled or dense-graded asphalt. Use of diesel oil as a releasing/cleaning agent is widespread in the hot mix asphalt paving industry and can contribute significantly to worker hydrocarbon exposures, including PACs, which may also be present in bitumen emissions (Cavallari et al 2012a(Cavallari et al , 2012bOsborn et al 2013).…”