Dust Control

Gravel roads will generate dust in varying amounts based on the amount of traffic the road sees and the type of weather the seasons bring. Linn County Secondary Roads applies safety chloride to various road and rock overlays each season. 

View the 2022 Linn County Secondary Road Chloride Application Map.

Additionally, applications to help control the amount of dust produced are available through the county to be applied by the individual property owner, private contractor or the county with an approved permit. Property owners can sign up for dust control application during these dates:

First Sign Up Period: April 1 - May 10

  • First application of calcium chloride
  • Application of oil (MC-70) or seal coat
  • Application by private contractor

Second Sign Up Period: June 1 - July 10

  • Second application of calcium chloride
  • Application by private contractor

Individuals may sign up by calling the Linn County Engineer’s Office at 319-892-6400 or by completing a permit and mailing it to the office (1888 County Home Road, Marion, IA 52302) with a check made payable to the Linn County Treasurer. Information about sign up dates and the dust control products available through the county is available in our Dust Control Information Sheet (PDF).

View the County’s Fugitive Dust Control Policy (PDF).

Dust Control Permits

Individuals having dust control applied to county roads adjacent to their property must obtain a permit through the Linn County Engineer’s Office, regardless of who is doing the application. If you are hiring a private applicator, are applying it yourself or are wanting to maintain previous years oil or seal coat, the permit fee is $50 and is non-refundable. If you are having the county apply the dust control, the fee is the cost per foot for the length you are wanting applied. All fees are due prior to dust control being applied.

Types of Dust Control

There are multiple options for dust control on rock roads. The county offers calcium chloride, oil and seal coat. Applications must have a minimum of 150 feet with any additions past that in 50 foot increments. Additional products are available through private contractors.

Note: No product will produce a completely dust free experience.

Calcium Chloride - $0.75 per foot per application (2022 price)

Calcium chloride is a liquid salt solution sprayed directly onto the rock surface. This product works to draw water from the air into the road maintaining its effectiveness in dry weather. It is water soluble and two applications per year is recommended.

Oil (MC-70) - $4.00 per foot (2022 price)

Asphalt cut back is placed on the rock surface and a light layer of rock or sand is applied to help cover the liquid until it is hard. A permit for oil is for a single application. One application can last a full season or more if maintained by the owner. Owners planning to seal coat must have intact oil or apply oil as a tack coat prior to the seal coat application.

Seal Coat - $4.50 per foot - over an existing Oil or Seal Coat (2022 price)

A seal coat is a thicker cut back and rock chips placed on a prepared base. Seal coat requires oil (MC-70) to be placed as a tack coat before application. If the oil has not already been applied, the cost to complete the seal coat process is $8.50 per foot. Additional seal coat applications can be made over top as long as the surface has been maintained and is in good shape. The surface with the seal coat will become dust free over time with rain and traffic.