Dear NoVA Buyer,
As convenient as it would be, studies done a couple of years ago in Los Angeles suggest that humans should not live within 1.5 miles of a highway, not to mention a mixing bowl. The health concerns include carcinogenic ultrafine particles that are harmful to asthmatics and cause lung damage as well as shortened life spans. Additionally, polycyclic aromatics which are airborne compounds from auto pollution have been linked to pre-term births and low birth weights and suggests DNA damage.
With that said, for affordability and air quality, I would suggest looking in West Springfield 22153. A little farther north in the Annandale 22003 (west of 495) you can find some nice homes and low prices in the $445k-$490k range.
If you would care for more information, I would be happy to help.