The Lesser Known Vehicle Emissions You Should Know About

I’ve been a master technician in the auto repair industry for 50 years. The first emission control system I ever saw was a pipe sticking out of a rocker cover, belching filthy crankcase gases directly into the atmosphere.

Pollutants have harmed our health and damaged our environment for decades. Today’s emission systems, thankfully, produce virtually no measurable tailpipe emissions (smog). This is great news for our overall health and environment.

Two recent studies, by the Harvard T.H. Chan School of Public Health and University of Southern California’s Keck School of Medicine, show decreasing vehicle emission “have reduced by thousands the number of deaths attributable to air pollution.”

There’s also “real-world” evidence that, as we transition to electric vehicles (EVs), improved air quality has substantially reduced the number emergency department visits for asthma.

However, other lesser-known vehicle pollutants — labeled non-exhaust emissions (NEE) — are still an issue. You may be surprised at what we found, and what’s being done to lower these emissions.

Tailpipe Emissions (aka Smog)

Smog is a catch-all term for gases and other harmful pollutants that escape from your vehicle’s exhaust into the atmosphere. According to the United States Environmental Protection Agency (EPA), the U.S. transportation sector annually accounts for more than 25% of all airborne pollutants.

What’s being done: Effective 2023, the EPA established a Corporate Average Fuel Economy (CAFE) standard of 40 miles per gallons for cars and light trucks, a 60% increase over the previous standard. The goals? Reducing tailpipe emissions and speeding up consumer adoption of EVs.

Windshield Wiper Fluid

Though windshield wiper fluid consists primarily of water, additives like methanol, ethanol and isopropyl alcohol that keep it from freezing are volatile organic compounds (VOCs). Recent studies show wiper fluid could be a greater source of VOCs than vehicle exhaust. VOCS are a known air pollutant and health hazard.

What’s being done: Some environmentally friendly biodegradable washer fluids contain no VOCs, ammonia, solvents or other hazardous ingredients. Unfortunately, you’ll need to add ethanol or isopropyl alcohol for winter use.

Tires

Tires are made from more than 200 natural and synthetic compounds. Over their lifetime, from production to scrap, tires release toxic chemicals, greenhouse gases, particulate matter (PM), heavy metals and VOCs.

A study by the Yale School of the Environment shows that as tires wear, they release more environmental and health pollutants than a car’s tailpipe. The study also found almost 30 percent of the environmentally damaging microplastics in our waterways come from tires.

What’s being done: The U.S. Tire Manufacturers Association is working to identify more sustainable materials. It’s also changing manufacturing processes, fostering ecological friendly scrap tire markets and designing tires with less rolling resistance to improve gas mileage.

Brake Dust

Abrasion between disc brake pads and rotors generates brake dust. Brake pads and dust contain heavy metals, carbon, copper, brass, graphite, fiberglass and even ceramic fibers.

According to a 2020 study, brake dust “is the most abundant NEE particulate measured” and releases more fine particulate matter than exhaust smog. Brake dust causes respiratory inflammation and weakens the body’s ability to fight off bacteria.

What’s being done: The automotive industry and EPA agreed to gradually decrease the use of copper and other harmful materials found in brake pads.

And drum brakes are making a comeback! Innovative designs, materials and technologies will lessen the amount of dust brakes produce and improve their stopping power. Plus, brake drums trap and hold brake dust until thoroughly cleaned and discarded.

Drum brakes are perfect for EVs, which use regenerative braking (the electric motor rotating backward) to slow a vehicle. This results in minimal brake wear and less brake dust.

Road-Dust Resuspension

Rarely discussed, road-dust resuspension (RDS) describes particles like dust, pollutants, contaminates, salts, animal waste and fertilizer on a road’s surface, especially unpaved ones. These get tossed back by rolling tires and suspended in the air.

Sometimes referred to as “fugitive emissions,” RDS raises the concentration of PM in the air, causing respiratory irritation or cardiovascular problems.

One fact I found peculiar: Catalytic converters reduce smog and emissions but contribute to RDS. As catalytic converters age, their heavy and noble metals begin to break down and end up as RDS. With the average age of cars at 12 years, this becomes an ongoing problem.

What’s being done: Unfortunately, not a lot.

The EPA has conducted numerous studies measuring the effects of RDS. Their recommendations include more frequent street washing and vacuuming, spreading non-toxic chemical suppressants and adding plantings close to roadways to control dust. More sustainable tires, plus new pavement materials now in use, should also decrease road dust resuspension.

New Car Smell

That indisputable smell of a new car is exciting. But it comes from various materials in your new ride that off-gas hazardous VOCs. The worst? Two toxic, cancer-causing VOCs, benzene and formaldehyde, found in adhesives, sealants, fabrics and plastics.

What’s being done: The EPA implemented Mobile Source Air Toxics (MSAT) rules to decrease these hazardous pollutants. Car manufacturers are utilizing eco-friendly waterborne rather than solvent based paints/coatings, as well as other materials that release fewer VOCs. Plus, newly-designed vehicle HVAC systems disperse VOCs more quickly.