The American Housing Survey estimates 12 to 15 percent of the
US population lives within 50m of main roads and freeways. Similarly, it is now
being proven that pollutants are significantly heavier in such locations
(fairly obvious, but now there is data coming out to verify this). If you combine that
with the fact that the Obama stimulus package is injecting large amounts of money into road
construction, the need for additional near roadside
air quality monitoring will undoubtedly increase.