1.   Because carbon monoxide is created primarily by vehicle exhaust, the pollution advisories target driving.

2.   Benzene is found in vehicle exhaust, and can cause leukemia.

3.   A cloud of toxic vehicle exhaust hangs over the city.

4.   Fine particles come from vehicle exhaust, power plants, factories, refineries, brush fires and even living-room fireplaces.

5.   He thinks the devices are important, but not the cure-all for cleaning up vehicle exhaust.

6.   Normally, carbon monoxide levels build gradually, fueled by vehicle exhaust trapped in stagnant air.

7.   Since then, Massachusetts air has gotten cleaner, and regulators have come up with more consumer-friendly ways to test vehicle exhaust.

8.   Smog comes not only from vehicle exhaust but also from factory and power plant smokestacks and from emissions of volatile organic compounds, like fuel vapors.

9.   That same car also would be creating vehicle exhaust, which contributes to a pollution problem that, as Austin grows, could lead to strict federal regulations.

10.   Vehicle exhaust is the biggest single contributor to ozone pollution.