Temperature-Dependent Chemical-Specific Emission Rates of Aromatics and Polyaromatic Hydrocarbons (PAHs) in Bitumen Fume

Abstract

Chemical-specific emission rates for simple aromatic and polycyclic aromatic hydrocarbon compounds (PAHs) from bitumens during hot mix asphalt (HMA) production and placement activities were evaluated using a headspace gas chromatography method. Temperature-dependent headspace concentrations of the EPA listed aromatic and polycyclic aromatic compounds were measured in the laboratory using headspace gas chromatographs equipped with a variety of detectors. The methodology has previously been calibrated and verified by a program of simultaneous laboratory and field tests, and is accurate in identifying field inhalation exposure potential to individual compounds in asphalt fumes.The results indicated that chemical-specific emission rates of aromatic and PAHs are strongly linked to both the performance grade of the asphalt binder and the binder temperature. Individual chemical compounds were quantified for 22 paving grade bitumen sources from throughout the United States. Chemical-specific emission rates from each binder were measured at a series of temperatures spanning the range, typically used for application of HMA, and at temperatures well in excess of those used for HMA applications in the United States. Emissions of all detected compounds increased with elevating temperature. The amount and composition of PAHs were markedly influenced by changes in temperature. At binder temperatures at or below 190 • C, only very small amounts of mostly 2-and 3-ringed PAHs were emitted. Concentrations of individual two-ringed PAHs ranged from 0.5 to 11 μg/m 3 at 150 • C and ranged from 2.0 to 100 μg/m 3 at 190 • C. Concentrations of 3-ringed PAHs were below method detection level of 0.1 μg/m 3 and ranged from 0.1 to 120 μg/m 3 at 190 • C. Larger ring number PAHs were below detection at 150 • C and less than 10 μg/m 3 for 4-ringed PAHs at 190 • C. As binder temperature increased above the typical limit for HMA production and application, several PAHs with greater ring numbers (4-, 5-, and 6-ringed PAHs) and more potent toxicity equivalency factors (carcinogenic potential) were detected.

Characterization of Endocrine Disruptors and Particulate Matter Emissions from Laser Cutting of Plastic Film in the TFT-LCD Industry

“…Among the 16 PAHs, the increases in the concentrations of lowmolecular-weight PAHs (2-and 3-ring) were significantly higher than those of medium-(4-ring) and high-molecularweight PAHs (5-and 6-ringed). This trend is similar to those observed in previous studies (Grimmer, 1983;Lange et al, 2007). For PC, the highest ratio of gas phase/total concentration (about 99.9%) was found in 2-ring PAHs (such as NaP) when the laser power was 240 W, and the highest ratio of particle phase/total concentration (about 90.5%) was found in 5-ring PAHs (such as BbF, BkF, and BaP) under 240 W laser power.…”

Considering the future of anthropogenic gas-phase organic compound emissions and the increasing influence of non-combustion sources on urban air quality

“…Similarly, there were no IVOCs or SVOCs declared in the asphalt-containing products in our MSDS survey. Nonsolvent emissions during the hot storage, application, or resurfacing of these asphalts are caused by the degradation (i.e., fragmentation) of larger organic compounds from asphalts to form smaller compounds (C 7 -C 30 ), which include cyclic and acyclic alkanes, single-ring aromatics, PAHs (2ring, 3-ring, and 4-ring), and sulfur-or nitrogen-containing species (i.e., benzo-and dibenzo-thiophenes and furans), all of which were not present in the asphalt prior to heating (Cavallari et al, 2012b;Gasthauer et al, 2008;Kitto et al, 1997;Kriech et al, 2002;Lange et al, 2005;Lange and Stroup-Gardiner, 2007; The Asphalt Institute and European Bitumen Association, 2015). The total mass and composition of emissions is dependent on production methods, asphalt grade, and increases in magnitude and maximum molecular weight with storage and application temperatures (i.e., more SVOCs at high temperatures), which ranged 100-240 • C or higher for roofing asphalts (Cavallari et al, 2012c;Gasthauer et al, 2008;Kitto et al, 1997;Kriech et al, 2002;Lange et al, 2005;Lange and Stroup-Gardiner, 2007; The Asphalt Institute & European Bitumen Association, 2015).…”

Exposure to Diesel Motor Exhaust and Lung Cancer Risk in a Pooled Analysis from Case-Control Studies in Europe and Canada

“…In general, lowering of temperature of the bitumen mix at the paving sites has led to decreased exposure levels, and has changed the composition of exposure to PAHs. 67 A large number of epidemiological studies have described cancer risk in asphalt workers and roofers in various countries. 68,69 In particular, lung cancer excesses have been observed in roofers.…”