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Why is calcium chloride used to control dust and ice on roads?

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A labeled diagram of the periodic table entry for calcium, showing its atomic number 20, symbol Ca, atomic weight 40.078, electron configuration, and classification as an alkaline-earth metal. Icons indicate calcium is a solid with a face-centered cubic crystal structure and strongly basic oxides at room temperature. — calcium The chemical element calcium is the most abundant metallic element in the human body.

Calcium chloride is used to manage road conditions due to its chemical properties as a deliquescent salt.

Dust Control

The effectiveness of calcium chloride in settling road dust stems from its ability to absorb moisture from the atmosphere. When applied as a powder or flakes, it absorbs more than its own weight in water, creating a liquid that keeps the road surface damp and prevents dust from becoming airborne.1

Ice Control

Calcium chloride is highly effective at melting ice through a process known as freezing point depression. By dissolving into three separate ions—one calcium ion and two chloride ions—it disrupts the ability of water molecules to bond into a rigid ice structure more efficiently than salts that break into only two ions.2

While it is a powerful tool for road maintenance, it is important to acknowledge that chloride runoff can be harmful to the environment, as it may dehydrate plants, alter soil composition, and negatively impact aquatic life.2