Characteristics of traffic-induced fugitive dust from unpaved roads

Abstract

The characteristics of fugitive dust emitted from vehicles traveling on unpaved dirt roads were measured using a suite of instruments including a real-time fugitive dust sampler. The fugitive dust sampler is formed from a combination of a large particle inlet and an optical particle spectrometer that reports particle sizes from 6 to 75 mm. The large particle inlet permits the sampling of particles up to 75 mm with only a moderate dependence of sampling efficiency on wind-speed. Measurements made with the sampler showed that particles as large as »50 mm were suspended from vehicular movement on the dirt roads, with the mode of the fugitive dust particle number size distribution »2 mm, while the mass distribution mode was »7 mm. A comparison of the fugitive dust sampler measurements with those made using standard PM instruments showed that the conventional instruments have a wind-direction bias that can result in under-sampling of large particles. The current measurements suggest that particles suspended from dirt roadways are of importance for local air quality within the near-road environment.

Characterization of organic aerosol across the global remote troposphere: a comparison of ATom measurements and global chemistry models

“…The studies referenced to derive the emission ratio used ambient data in urban air, where all sources mix together and impact the POA / BC ratio, and thus the ratios include the impact of POA sources that may not emit BC. It should be noted that urban model ratios do not include emissions associated with fugitive dust from road, tires, and construction, as those are typically found in particles larger than those studied here (Zhao et al, 2017). For biomass burning sources, we use a value of POA / BC = 11.8 (BB ratio ) based on the average of the recent review by Andreae (2019), which included over 200 previous determinations for a variety of fuels and burning conditions (since Andreae, 2019, used an OA / OC ratio of 1.6 in his work, we have used that value to calculate POA / BC; we note that this is different from the 1.8 OA / OC ratio used for other studies listed in Table S1).…”

“…It is associated with adverse health effects (Mauderly and Chow, 2008;Shiraiwa et al, 2017) and contributes radiative forcing to the climate system (Boucher et al, 2013). The currently limited understanding of processes involved in the formation, aging, and removal of organic compounds results in large uncertainties in (i) the predicted global OA burden, (ii) relative contributions of emissions vs. chemistry to OA formation, (iii) spatial distribution, and (iv) impacts on radiation and clouds (Kanakidou et al, 2005;Hallquist et al, 2009;Heald et al, 2011;Spracklen et al, 2011;Tsigaridis et al, 2014;Hodzic et al, 2016;Shrivastava et al, 2017;Tsigaridis and Kanakidou, 2018;Zhu et al, 2019). The uncertainties are particularly large in the estimated global burden of SOA, which ranges from 12 to 450 Tg yr −1 (see Fig.…”

Quantifying Anthropogenic Dust Emissions

“…Cropland management practices can create mosaic landscapes with dust emission hot spots arising in response to tillage practices and crop rotations within individual fields (Bielders et al, ; Houyou et al, ; Lee et al, ; Rajot, ; Singh et al, ). Similarly, intensive landscape disturbances resulting from altered hydrological regimes (e.g., river diversion), energy development, graded road networks, and off‐road vehicle activity, modify land cover and potentially accelerate point‐source dust emissions (Goossens & Buck, ; Zhao et al, ). Wind erosion accelerated by LULCC influences soil nutrients and biogeochemical cycles, the land surface energy budget, and climate, with feedbacks that can promote further land cover change, dryland expansion, and increased dust emissions (D'Odorico et al, ).…”

Fugitive Dust Suppression in Unpaved Roads: State of the Art Research Review

“…Initially, Sanders et al [68] experimented with the efficacy of chloride-based dust suppressants on the unpaved road sections. Application of calcium chloride (CaCl 2 ) and magnesium chloride (MgCl 2 ) indicated a reduction of dust emission by 50-70% at an application rate of 0.5 gals/yd 3 [68]. Goodrich et al [90] studied the performance of MgCl 2 dust suppressant on the surface water chemistry next to the treated unpaved road in Colorado, USA.…”

“…A significant portion of these unpaved roads serve as a connection between rural farming communities and urban areas, and the rest of them facilitate pathways to forests, mining fields, and timber hauls [2]. On unpaved roads, fugitive dust emanates from the mechanical interaction between the moving vehicles and the crushed aggregates [3]. Fugitive dust primarily comprises soil minerals (e.g., oxides of silicon, aluminum, calcium, and iron) with particulate material sizes lower than 10 µm (PM 10 ) [4].…”