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Dust Control On Unpaved Roads and Surfaces (Code 373)


Unpaved RoadThe Natural Resources Conservation Service is offering conservation assistance by encouraging California growers to use new and innovative agricultural emission reduction practices and technologies that provide significant environmental benefits to our natural resources.

The Dust Control on Unpaved Roads and Surfaces practice standard improves air quality by treating unpaved roads and surface areas with dust suppressants.  Unpaved roads and surfaces can be significant sources of particulate matter (PM10) and visible dust emissions from vehicle traffic or wind actions across the unpaved surfaces.  Applying dust suppressants can stabilize the surface to help reduce PM10 and visible dust emissions, minimize dust deposition onto sensitive crops, improve traffic safety, and avoid nuisances.

The primary factors that generate PM10 and visible dust emissions from unpaved roads and surface areas include:

  • Vehicle Traffic Conditions:  The number of vehicle daily trips, number of wheels per vehicle, and vehicle types, weight and speed.
  • Surface Conditions:  Particle size distribution, compaction, cohesiveness, bonding and durability of the surface.
  • Ambient Atmospheric Conditions:  Humidity, precipitation, temperature, wind speed and direction, and evaporation.

Many varieties of dust suppressants are available and generally classified as water, hygroscopic products (e.g. road salts), organic petroleum products (e.g. liquid asphalt road oils), organic nonpetroleum products (e.g. lignosulfonates), electrochemical products, synthetic polymer products, and clay additives.  Other product types may include surfactants, solid materials (e.g. petroleum by-products blended with soils), vegetative materials (e.g. wood chips), and aggregates (e.g. gravel, recycled asphalt chips, etc.).  Because each category has its own characteristics, selecting an appropriate treatment will depend on how the dust suppressant coheres dust particles to larger particles, remains on the treated unpaved surface, and resists to vehicle wear, crop or animal activities, weather and aging.  Reducing vehicle speed or restricting vehicle access with gates and barriers can help reduce emissions and extend the effectiveness of the treated unpaved surface.

The Environmental Quality Inventive Program (EQIP) applies this practice towards treating unpaved roads and surfaces with approved dust suppressants.  These currently include SC-250 liquid asphalt road oil (SC-800 for more alkali soils), lignosulfonates, and synthetic polymers.  Each eligible application undergoes a screening and ranking process to consider the air quality benefits of any planned conservation practice, as identified by local, state, and national priorities.  Offered statewide, proposals for treating unpaved roads and surfaces within any PM nonattainment area of California will receive a higher priority.

Program Guidelines:  373 - Dust Control on Unpaved Roads and Surfaces

California growers must meet EQIP eligibility requirements to qualify for payments.

  • The contract length is two years.  A single payment in the first year of the contract. 
  • Eligible dust suppressants are SC-250 liquid asphalt road oil (SC-800 for more alkali soils), lignosulfonate, and synthetic polymer products.
  • The condition of the unpaved road and surface must be well prepared.  If necessary, the participant will grade the surface in a manner that supports water runoff and drainage by removing potholes, washboards, berms, tire ruts, and road surface erosion.  Moisten the road surface prior to performing any grading or mechanical work, as dry conditions will fill ruts and potholes with dust and dry materials that will either blow away or wash out during rain events.  Wetting also helps to limit PM10 and visible dust emissions caused by the mechanical work.
  • Apply the dust suppressant product topically in accordance with manufacturer recommendations.  The surface condition prior to application should maintain ¼-inch or more layer of fines for the product to penetrate the surface and assure properly binding.  Pre-wetting or subsequent topical applications may be necessary for product effectiveness.
  • The following table provides general guidance for the topical application of eligible dust suppressants.  Applying a higher concentration may be necessary for heavier-use roads and lower concentrations for subsequent or maintenance applications.  Because not all dust suppressants are alike, please consult with the manufacturer to determine the appropriate application rate for the site conditions.

Dust Suppressant

Square Feet per Gallon of Concentrate

Gallons of Concentrate per Square Yard

Dilution Rate

(Water to Concentrate)

Liquid Asphalt Road Oils

18 to 36

0.25 to 0.50



18 to 30

0.30 to 0.50


Synthetic Polymers

50 to 65

0.14 to 0.18


The participant may consider to:

  • Apply aggregate or a road-base material prior to topically applying the dust suppressant to improve product effectiveness, especially on more sandy or silty-type soils.
  • Install 15 MPH or slower speed limit signs to reduce the risk of vehicle wind actions lifting dust.
  • Place barriers or gates to restrict vehicle traffic and maximize treatment effectiveness.
  • Blend the dust suppressant product with the parent or imported road-base material to provide structural integrity for heavier vehicles and a longer-term dust control solution, per manufacturer recommendations.
  • Plan for maintenance applications after the term of the contract to assure that the treated surface remains in good condition.
  • Apply dust suppressants in a manner that will not affect plants, animals, or aquatic life.  The participant must select a dust suppressant product that is safe and appropriate for ground application.  Never use waste oil as a dust suppressant, as it is a hazardous waste.
  • Depending on the site conditions and type of product applied, it may be necessary to restrict vehicular traffic for a period after application to allow the dust suppressant product to cure.  Follow manufacturer recommendations.
  • Organic producers should consult with their certifying organic organization to identify any restrictions or limitations prior to applying any dust suppressant product.
  • Payments are not available for:
  • Subsequent product applications after the initial application within the contract period;
  • Installing barriers or speed limit signs;
  • Preconditioning or maintaining the unpaved road or surface area;
  • Importing and applying aggregate or base materials;
  • Treating previously paved roads, road shoulders, or vegetated or fallow areas; or,
  • Treating unpaved roads and surface areas serving rangeland or forestland.
  • The practice lifespan is one year.

For More Information

For more information about the Environmental Quality Incentives Program (EQIP), please contact your local USDA Service Center, listed in the government section of the phone book under U.S. Department of Agriculture. Information is also available on the Internet at


Updated: 10/30/2017