Researchers at the University of Georgia demonstrated that green spaces along roadways can cut pollution from vehicle exhaust. The findings were reported in the journal PLOS One, confirming a measurable impact of roadside vegetation on air quality.
Green strips beside roads act through several processes. They offer a wide surface area where tiny particles can settle out of the air, helping to remove contaminants as air moves past. In addition, plants can alter local wind patterns and humidity, which influences how pollutants disperse.
Measurements collected over six months at five highway sites showed meaningful changes. Soot concentrations decreased by about 37 percent when vegetation was present, while ultrafine particle levels dropped roughly 7 percent compared with similar, vegetation-free locations. These results suggest that trees and shrubs along roadsides contribute to cleaner air, though they do not eliminate the problem entirely.
Lead author Robie Greenwald commented that trees and shrubs along road corridors do not single-handedly solve vehicle pollution, but they do lessen its severity. He emphasized that expanding roadside planting is worthwhile because the benefits extend beyond aesthetics, including improvements to air quality and public health. [Source: PLOS One]
Beyond planting efforts, other strategies can reinforce progress. Strengthening public transit networks can reduce the number of vehicles on the road, while enhancing cycling and pedestrian infrastructure can make sustainable travel options more convenient. These measures work in concert with roadside greenery to improve urban air quality and create healthier communities. [Source: PLOS One]
Additional context from prior research indicates that brake wear dust may pose risks to health that are at least as significant as exhaust alone. This underscores the need for a broad approach to air quality, combining vegetation, transport policy, and engineering controls to reduce exposure to harmful particles. [Source: PLOS One]