Roadside exhaust sniffers caught almost 900 vehicles in Northern Virginia last year

Little green boxes placed on roadsides around Northern Virginia to automatically sample passing vehicles’ exhaust generated just under 900 air quality violations last year, which are mailed to the offending vehicle’s owner along with a photo and instructions to make repairs or face a fine.

The program is part of an effort to improve air quality in the region that began in 1982 and requires emissions inspections every two years for certain vehicles in Arlington, Fairfax, Loudoun, Prince William, Stafford counties and the cities of Alexandria, Fairfax, Falls Church, Manassas and Manassas Park.