Smog-reducing roof shingles help wash away air pollution

According to the American Lung Association, more than four in 10 Americans currently live in counties with unhealthy levels of ground-level ozone or particle pollution.¹ Globally, it’s even worse: A staggering 95% of people live in unhealthy air quality conditions according to World Health Organization standards.² Unhealthy levels can translate into cardiovascular, respiratory, neurological and other physical challenges³ that take their toll on people in those areas.

At 3M, we’re working on many ways to address these challenges. One of the most innovative and unexpected tools? A new generation of coated roofing granules powered by the sun.

Inspired by a roofing manufacturer’s curiosity about air pollution control, 3M™ Smog-reducing Granules were created and launched in 2018 by the 3M Industrial Mineral Products Division.

These tiny granules have a specialized photocatalytic coating that 3M applies to the base mineral on the granules surface. When sunlight hits the shingles, the sun’s ultraviolet rays transform pollutants—such as nitrogen oxide gases—into a plant-usable form of nitrogen that washes away.

In one early test, shingles with a blend of 95% standard granules and 5% 3M Smog-reducing Granules were sent to Lawrence Berkeley National Laboratory for evaluation. They were exposed to nitrogen oxides in a reaction chamber. Nitrogen oxide concentrations were recorded in real time prior to, during and after UV illumination. The result? 3M was able to calculate that each ton of these granules used in shingles has the capacity to capture the annual smog created by one car driven 3,000 miles.

Each ton of 3M Smog-reducing Granules has the capacity to capture the annual smog created by one car driven 3,000 miles.

“The roofing granules are a first for residential asphalt shingles,” said 3M Laboratory Manager Maureen Kavanagh. “The 3M granules will help roofing manufacturers develop high-quality, aesthetically pleasing shingles that can turn any roof into an active, smog-reducing catalyst.”

Lara Ughetta, Commercialization Leader for 3M Smog-reducing Granules, concurs: “We look at what the impact of this product can be, and it’s pretty mind-blowing when you start adding up the aggregate effects of individual roofs being turned into smog-reducing surfaces. It could make a big difference, especially in communities where smog has been a persistent problem.”

“We view smog-reducing technology embedded into mainstream roofing materials as a great step forward in addressing society’s air quality and climate concerns,” said Jonathan Parfrey, Founder and Executive Director of Climate Resolve, a U.S. nonprofit organization focused on local solutions to global climate change.

The 3M Smog-reducing Granules are just the latest eco-friendly technology in roof shingles. Here are a few other products that contribute to climate improvement.

Shrinking urban heat islands

Roofs and pavement make up about 60% of surfaces in some U.S. cities. When the sun is shining, this concentration of warmed surfaces can turn the heat up an extra 3 or 4 degrees, according to Berkeley Lab’s Heat Island Group.

Enter 3M™ Cool Roofing Granules. They’re up to four times more reflective than other standard colored granules, based on 3M’s reflectivity test methods. That helps communities bring down the urban heat island effect on scorching summer days.

Reflecting on the commercial roofing scene

3M™ Highly Reflective Granules are a component in asphalt cap sheets, installed on commercial low-slope roofs. They’re designed to reflect 70% of solar rays for 30 years or longer in a category where many of the alternatives fail in 10 years or less.

1 American Lung Association. State of the Air^© 2019 https://www.lung.org/assets/documents/healthy-air/state-of-the-air/sota-2019-full.pdf. Accessed on November 13, 2019.

2 Health Effects Institute. 2018. State of Global Air 2018. Special Report. Boston, MA:Health Effects Institute.

3 American Lung Association. Health Effects of Ozone and Particle Pollution. (2017). www.lung.org/our-initiatives/. Accessed on November 13, 2019.