Dust and More Dust
By James D. Ritchie

Living on a gravel road, you can depend on one fact of life every summer—dust. Here are some ways to deal with it.

A pickup goes past, lifts a powdery plume from the road. The dust swirls and glints in the summer sun, then settles like sifted flour onto the grass and shrubs along the edge of the yard. It’s not a good day to have laundry hanging on the line.

For many of us, dust is a nuisance—one of the drawbacks of living in the country. But for people with chronic respiratory problems, dust can be a real health hazard. It’s one of the six major air pollutants monitored by the Environmental Protection Agency. About two-thirds of America’s roads are unpaved, and EPA says 40 percent or more of dust particles in and around a rural home come from dirt or gravel roads.

All unpaved roads produce dust in dry weather—some more than others—depending on conditions and the amount and kind of traffic. Roads surfaced with river or creek gravel usually give off less dust than those topped with crushed limestone rock. Trucks and other heavy vehicles churn up more dust than pickups and passenger cars.

In the past, some rural residents spread waste crankcase oil to hold down the dust, but time has taught that this is an environmental no-no. Anything applied to a road surface can find its way into groundwater, and there are safer solutions than used engine oil.

So, what can you do about the dust boiling up in front of your homestead short of paying to have the road paved or standing watch with a garden hose?

There are several options:
Chloride salts, especially magnesium chloride and calcium chloride, which absorb moisture from the atmosphere and bind it to particles in the road. Chloride salts are corrosive to metals but are effective as long-term dust control and are reactivated by rain.
Approved road oil, such as MC-30 prime oil, keeps down the dust with one or two applications per year. Oil needs to be incorporated into the top layer of gravel, but over several applications, forms a surface much like blacktop.

Lignin sulfonate (tree sap), is a by-product of pulpwood processing. When the material is properly applied and incorporated, lignin sulfonate binds with gravel to seal road surfaces. Lignin sulfonate is biodegradable and is used primarily for commercial
dust control.

Soapstock, a by-product of solvent oil extraction from soybeans and other oil seeds, is also biodegradable and non-corrosive. Soapstock penetrates the road surface and bonds particles together for 3 to 4 months per application.

Polymer-based synthetic dust control agents are clear and odorless, and they can be applied without the need for water dilution. These materials are effective when applied in virtually any weather. Applied properly, one application reportedly provides year-round dust control.

Due to the cost—especially the cost of shipping—buying small amounts of any of these products can be prohibitive, unless you live next door to the plant that produces them. Often, neighbors can join forces to buy dust-suppressing materials in greater volume. Some counties (and special road districts within a county) apply dust control materials for property owners who request it—usually at or near the cost of the material.

“We apply magnesium chloride for about 150 property owners,” said Derin Campbell, engineer with the Audrain County (Mo.) Bridge Department. “We try to treat roads as soon after May 1 as possible to have the material on before hot, dry weather comes along.

“Early in the year, we publish an announcement in all county newspapers,” Campbell added. “Property owners come in and sign up. We arrange with Scotwood Industries to apply the material, and we only charge for the chemical and the water it’s mixed with. The cost on a typical county road is just over $1 per linear foot, and the landowner pays in advance.

“The minimum length of road to be treated is 300 feet, and there is no maximum length,” he went on. “We grade the road to be treated; Scotwood brings a tanker truck with spray boom and an operator; we treat all areas at the same time. I like using magnesium chloride because it is sprayed over the top, whereas something like road oil must be incorporated.

“Magnesium chloride bonds with road aggregate pretty quickly, but if a vehicle is driven over the road right after the material is sprayed, the mag chloride solution can stick to wheels and in fender wells. It should be washed off right away. Once the material dries and cures, there’s no problem. However, if magnesium chloride is accidentally sprayed onto a paved surface, it can be very slippery for a while.”

In Marion County, Mo., Howard Lovelace, county road supervisor, does things a bit differently.

“We use MC-30 road oil to control dust where a landowner requests it,” said Lovelace. “Oil is getting more costly all the time; road oil is now over $2 per gallon. But we maintain 75 miles of paved county road, so we already have an oil distributor and an operator. Once a property owner gets on the list, we maintain dust control on his stretch of road from year to year.

“For the past 3 years, some landowners have opted to use calcium chloride, which is cheaper than oil and gives 75 percent to 80 percent dust control,” Lovelace added. “We can obtain the calcium for them. A 50-pound bag of calcium chloride pellets will do a strip of road 8 feet wide and 90 feet long, and costs $13. The property owner can broadcast the dry pellets on his road and activate them with water from a sprayer or garden hose. Rain reactivates the calcium to some extent, but it can make a road rougher and in need of more maintenance. I still prefer to use oil.”

Few counties who are doing dust abatement are looking to expand the service. County road budgets are tight and getting tighter.

“In some areas, I think there’s an opportunity for entrepreneurs to get into the dust abatement business,” said Derin Campbell. “They would need to work with local road departments, but most counties would be happy to have some of the load lifted.”

Dust control options
If you want more information on specific dust-control products, here are places to start:

Dustlock is a biodegradable dust control made from the by-products of vegetable oil refining. In addition to dust control, Dustlock also provides erosion control. Contact Howard Hamilton, Environmental Dust Control, Inc., Phone: 507/763-3481. On the web at: www.dustlock.com

Durasoil is a synthetic organic dust control agent that is non-corrosive and needs no curing time after application. Durasoil can be applied with any kind of spraying equipment, in virtually any weather. Contact Shari Noland at Soilworks LLC. Phone: 800/545-5420, or on the web: www.Soilworks.com

Another synthetic dust control product, recently patented by Midwest Industrial Supply, is now on the market. Actually, Midwest has patented several new dust control and soil stabilization products, all reportedly environmentally safe. For more information, contact Bob Vitale, Midwest Industrial Supply, at 800/321-0699. E-mail: custserv@midwestind.com

DustGard is a natural magnesium chloride material extracted from the Great Salt Lake in Utah. DustGard attracts moisture from the atmosphere and from the road surface to make a compact, dust-free driving surface. Contact Phil Collins, Scotwood Industries, at 913/851-3500. On the web at www.scotwoodindustries.com

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