Dust trailing cars on dirt roads. Dust blowing across farm fields. Dust kicking up from mines and construction sites.
Counties and companies constantly battle to control dust—especially on roads. But is spending so much time and money on road dust control necessary? Yes!
Dust can be dangerous, so road dust control is essential. To better understand why, let’s examine what dust is, how it forms, and the problems it causes.
The definition of dust is “fine, dry powder consisting of tiny particles of earth or waste matter.” Those tiny dust particles are made of all sorts of substances.
The house dust behind your refrigerator is made of dirt, dead skin, human and pet hair, dust mites, clothing threads, bits of dead bugs, pollen, and tiny pieces of plastic.1 (We know you’re thinking it, so we’ll say it: Gross!)
Outdoor dust contains a higher concentration of soil particles like sand, rock, and clay. Clay-based soils are prone to become dusty because clay particles are small; they dry out quickly and blow through the air easily. Outdoor dust also contains natural matter like plant and animal residue, pollen, bacteria, smoke, ash, and ocean salt crystals.2 Road dust is a type of outdoor dust.
Classifying dust by its “ingredients” would be challenging since dust is made of so many things. Instead, people classify dust by size.
Dust particle size matters because smaller dust particles are more likely to go airborne, travel longer distances, and stay in the air for longer periods of time. That means people are more likely to inhale them, and they’re more likely to land places they shouldn’t go.
You’ll most commonly hear people talk about PM10 dust and PM2.5 dust.
PM10 dust stands for particulate matter, 10 micrometers. These dust particles are 0.01 millimeters wide or less. PM2.5 dust is even smaller. It’s just 2.5 micrometers—0.0025 millimeters—or less.
Some dust particles are so tiny, they’re only visible with a microscope. Others are large enough to see with the naked eye. Both PM10 and PM2.5 dust particles are small enough to inhale. (More on that soon.)
Dust forms when large matter particles break down into small particles and dry out. It can occur naturally, or it can be man-made.
Dust often forms naturally when wind erodes tiny pieces of soil or rock, then lifts them into the air. Man-made dust comes from a variety of industries and activities, like farming, building, or driving.
Dirt and gravel roads produce man-made dust. Cars drive over soil and rocks on the road surface, crushing those materials into small pieces. Those particles dry out and—presto! Your county road needs dust control. Unpaved roads are dustier in summer than other seasons: hot, dry days decrease soil moisture. Without moisture weighing them down, small soil particles dry out and become dust.
We humans create millions of tons of dust with our everyday activities and industries, such as:
These activities give us food to eat, homes to live in, and other essentials to survive, so people won’t stop doing them. Rather, we try to control dust by limiting activities that cause it, passing regulatory laws, and using dust suppressants, especially for road dust.
Without control measures, dust can cause serious problems. Let’s take a look.
You can find dust everywhere, from the ground to the air. And many dust particles are dangerous—especially on roads.
Low visibility sounds insignificant. After all, it implies that you can still see something. However, low visibility due to road dust causes serious, deadly automobile accidents.
In May 2023, more than 70 cars and heavy trucks collided in a chain reaction that killed six people and injured dozens more. The cause? Agricultural dust blowing across I-55 in southern Illinois.3
On rural roads with light traffic, a 70-car pileup is thankfully unlikely, but fatal collisions are still a risk. Dusty rural roads can blind drivers, causing them to strike other vehicles, animals, trees, ditches, or nearby structures. No family deserves to lose a loved one because of road dust.
Some dust helps the environment. For example, scientists suggest that increased dust could counteract greenhouse gasses and global warming.4 And Saharan Desert dust drifting into the Atlantic Ocean delivers vital iron, phosphorus, and nitrogen to phytoplankton, which then bloom and feed sea creatures.5
So, dust isn’t all bad. However, too much dust or dust containing harmful particulate matter pollutes our water and soil.
Dust changes water’s acidity and nutrient balance, and it can even cause acid rain. This can make water undrinkable. People, plants, and animals using contaminated water may get sick. Dust also depletes soil’s nutrient reserves, carrying them away when the wind blows.6
Polluted soil and water make it harder for plants to grow—including food crops and sensitive, endangered ecosystems. Additionally, some plants die when dust coats their leaves; dust blocks their photoreceptors so they can’t absorb enough sunlight.
Dust particles are small but mighty. They scratch metal, take paint off cars, and even scrape stone. That’s why cars driving on unpaved roads tend to suffer more paint damage over time than cars driving on asphalt.
When dust causes acid rain, it can corrode metals and deteriorate stones—damaging both vehicles and structures.7
Dust also poses a problem for solar farms. When dust coats solar panels, they can’t convert sunlight into energy as efficiently (much like dusty plants). Solar farm operators go to great lengths to keep dust off their panels.
According to the American Chemical Society, dust particles carry contaminants for years, keeping hazardous chemicals around even after they’re banned.8 Road dust particularly soaks up oil, coolant, hydraulic fluid, pesticides, and other chemicals. These contaminants then make their way into soil, water, food, and our lungs.
The most common health risks associated with dust are mild to moderate respiratory issues like allergies and coughing. Some people may also experience irritated eyes and skin after dust exposure.
However, the health risks increase with prolonged, frequent, or excessive exposure. Inhaling dust particles or getting them on our skin can cause serious health issues, including:
Some researchers even suggest that chemically contaminated dust could contribute to weight gain.11
Dust affects everyone, but the risks are highest for people with occupational exposure—jobs that put them around large volumes of dust. For example, street sweepers have more health issues from road dust than the average person.12
To recap, dust is made of small particles of dry matter. It forms naturally and through human activities like driving on roadways.
All types of dust—including road dust—pose risks like low visibility, environmental damage, property damage, chemical contamination, and health issues. With so much at stake, eco-friendly road dust control is an essential part of keeping our communities healthy and safe.
Learn about dust control solutions for dirt roads, plus which ones we recommend.
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