Long-Term Efficiencies of Dust Suppressants to Reduce PM₁₀ Emissions from Unpaved Roads

Abstract

A 14-month study was undertaken to assess the long-term efficiencies of four dust suppressants (i.e., biocatalyst stabilizer, polymer emulsion, petroleum emulsion with polymer, and nonhazardous crude-oil-containing materials) to reduce the emission of PM 10 from public unpaved roads. PM 10 emission rates were calculated for each test section and for an untreated section for comparison purposes. Emission rates were determined from PM 10 concentrations measured from 1.25 m to 9 m upwind and downwind of the road and above its surface. Calculated emission factors ranged between zero and 1,361 g-PM 10 /vehicle kilometer traveled (VKT) (average uncertainty = ±35 g-PM 10 / VKT) for the four types applied. One week after application, suppressant efficiencies ranged between 33% and 100% for the four types applied. After 8-12 months of exposure to weathering and 4,900-6,400 vehicle passes, the suppressant efficiencies ranged from zero to 95%. Roadway surface properties associated with low-emitting, well-suppressed surfaces are (1) surface silt loading and (2) strength and flexibility of suppressant material as a surface layer or cover. Suppressants that create surface conditions resistant to brittle failure are less prone to deterioration and more likely to increase long-term reduction efficiency for PM 10 emissions on unpaved roads. IMPLICATIONS PM 10 emissions from unpaved roads constitute large fractions of emission inventories. Chemical suppressants often are recommended to reduce these emissions, but the effectiveness of these measures over time has not been proven. This study shows that several suppressants do not stand up to long-term wear and tear from vehicles and weather. Treatments that resist brittle failure of the surface have the greatest potential to create long-term dust reductions. Inexpensive surface property measurements can be applied to establish quantitative performance standards for suppressant acceptability.

Effect of vehicle characteristics on unpaved road dust emissions

“…From 11-24 April 2002, unpaved road emission flux experiments were conducted at Ft. Bliss, TX, using an upwind/downwind measurement technique similar to Gillies et al (1999). Three towers were set up collinearly and perpendicular to a 1000 m section of unpaved road.…”

Deposition and Removal of Fugitive Dust in the Arid Southwestern United States: Measurements and Model Results

“…The experimental procedure was-based on an upwind/downwind technique that has been used by other investigators (e.g., Gillies et al 23 and Cowherd 24 ). Three towers were set up collinearly and perpendicular to a 1000-m section of unpaved road (Figure 2), which was oriented in a northsouth direction.…”

Particulate Emissions from U.S. Department of Defense Artillery Backblast Testing

“…The mechanics of the backblast process are very different from other fugitive emission sources. 1,11,12 The emission mechanism is hypothesized to be the force that is transferred to the soil surface by the detonation of the propellant. As the backblast force impacts the earth surface at the gun position, the earth responds by compressing and then rebounding.…”