Dust Palliative Basics

Dust palliatives are substances that are applied to the surface of a road to help reduce the volume of airborne dust and its negative health effects. These palliatives could be applied as often as every few hours on busy construction sites or as infrequently as every few years at sites that don’t get a ton of traffic. Let’s delve into more details provided by our experts at Ninja De-Icer.

Dust Palliative - What Is It and How Does It Work? 

There are different kinds of dust palliatives that are designed for different use cases. This is a huge business as “fugitive dust” needs to be controlled at various construction and industrial sites across the country to keep workers safe. When a dust cloud is created and there aren’t dust palliatives around, those potentially damaging fumes circulate into the air and can cause health issues. 

The most commonly utilized dust palliatives include lignin sulfonate and magnesium chloride. Lignins act like glue in dust control and surface stabilization and it’s derived from the lignin that naturally binds cellulose fibers together to give firmness to plants and trees. Magnesium chloride is a naturally biodegradable salt that helps to control dust on a variety of road types. 

There are two main ways that palliatives work; some work by increasing the moisture content in the road while others work to bind particles together.  

Dust Palliative Working by Increasing Moisture Content

When there’s moisture on the surface of a dirt road, it causes the particles to stick together. This moisture content can be increased by spreading water or applying salts (like magnesium chloride) that attract water. Applying deliquescent salts to the surface of the road helps to control dust by absorbing water from the air. When soils are treated with these types of salts, they have a higher water content than untreated soils. The rainfall also eventually removes the salt from the roads. 

Dust Palliative Working by Binding Particles Together

Other dust control products work by binding particles in the road together. They work by binding fine particles together or onto larger particles. Chemicals in this group of dust palliatives fall into different groups such as organic nonpetroleum, petroleum-based, electrochemical stabilizers, and synthetic polymers.

Examples of petroleum-based binders include cutback asphalt, emulsified asphalts, and Bunker C. These work to coat the particles with a thin asphalt layer to increase the mass of the particle and decrease the chance of airborne particles. Organic nonpetroleum dust suppressants include resins and lignosulfonates. Electrochemical stabilizers include bentonite, ionic stabilizers, and sulfonated petroleum. They work to neutralize soils that attract water and create bonds between particles. Finally, synthetic polymer products include acetates and polyvinyl acrylics. Let’s explore the main types of dust palliatives below. 

Main Types of Dust Palliatives

• Water

Water is the first major category of dust palliatives and it is one of the most commonly used types. 

• Water Absorbing Products

Water-absorbing products are broken into three categories: magnesium chloride, sodium chloride, and calcium chloride. Our team has extensive experience in using these types of palliative and we’re happy to answer any questions you may have. 

• Organic Petroleum Products

Organic petroleum products include dust oils, asphalt emulsions, cutback asphalt, and modified asphalt emulsions. 

• Organic Nonpetroleum Products

Organic nonpetroleum products include animal fats, vegetable oils, lignosulfonate, tall oil emulsions, and molasses/sugar beet. 

• Electrochemical Products

Examples of electrochemical products include enzymes, ionic products, and sulfonated oils. 

• Synthetic Polymer Products

Examples of synthetic polymer products include vinyl acrylic and polyvinyl acetate. 

• Clay Additives

Clay additive examples include bentonite and montmorillonite. 

Before Work Preparations 

Make sure to pinpoint construction activities that require the use of dust palliatives. We’ve outlined some examples of activities that could require dust control below:

• Grading, clearing, and excavation
• Unpaved roads and staging areas
• Stockpiles
• Demolition of concrete 
• Soil loading and unloading

In the case that a dust suppressant or dust control binder is used, make sure that the contractor submits a dust treatment plan beforehand. You’ll want to review this treatment plan for rates and application methods, weather conditions, and drying or curing time. 

Dust Palliative - Selection Tips 

When choosing your dust palliative, you’ll likely want to choose the most cost-effective option. But there are several other factors to consider, including:

• Resisting wear by traffic
• Remaining on the road
• Resisting aging
• Cohering the dust particles to themselves or larger particles

You can also perform a soil analysis before you classify the surface material. Some dust palliatives require a clay component (plasticity index) or a specific amount of fines to successfully bind and/or agglomerate. Some factors that could improve the dust palliative selection include application methods, dust suppressant limitations, and environmental impact. 

Dust Palliative - Application Tips 

How well your dust suppressant performs depends on many different application factors including rate, method, frequency, and product concentration. By properly applying the dust palliative of your choice, you help to extend its lifespan while maintaining a higher level of surface.

Here are some application tips for you to consider:

• If possible, apply suppressants (especially salts) right after the wet season.
• Apply after rainfall so materials are wetter and more workable for better mixing. If you apply the material before the rain, it could wash away.
• If you see a hard crust forming, break up the surface.
• Follow the manufacturer's recommendations on the application rate, curing time, and compaction before you allow traffic.
• Use a pressure distributor to evenly distribute the dust suppressant.
• If the material becomes dry make sure to dampen it, except when you’re using cut-back asphalt products.
• Make sure to obtain the “residual” of the product (the amount of product that remains after the evaporation of water from the concentrate).

Are Dust Palliatives Eco-Friendly? 

The environmental impacts of dust palliatives should also be considered. The main concern is how dust palliatives could impact the quality of the groundwater, freshwater aquatic environment, and the plant community. Always take the necessary precautions to keep the dust palliative material out of roadway ditches and water drainages as it could end up in a stream. 

Make sure that you are following all local, state, and federal regulations when applying your dust palliatives as there are discrepancies between locations. Each state also has its standards when it comes to how dust palliatives impact the freshwater aquatic environment, measuring impact by toxicity to fish and oxygen availability levels. 

Dust Palliatives’ Advantages 

When lignins are used for dust control and surface stabilization, it comes with many advantages such as:

• Non-corrosive
• Water-soluble
• Eco-friendly, non-toxic
• Cost-effective
• No special equipment or clothing required
• Easy to handle and apply

There are many advantages to using magnesium chloride as a dust palliative, as well as other salts like calcium chloride and sodium chloride:

• No residue was left behind
• Eco-friendly
• Odorless, colorless
• Attracts moisture
• Can be used in temperatures as low as 5 degrees Fahrenheit

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Conclusion

Although airborne dust from roads can be frustrating, choosing the right dust palliatives can make a world of difference! We hope that you’re more informed about how to choose the right dust palliative. Ninja De-Icer specializes in water absorbing product options for dust control. If you’re wondering how our team can help, reach out to us today at Ninja De-Icer!