The air quality reached the highest level of pollution on a new system implemented earlier this year. Yesterday, the color-coded smog alert reached purple which means very unhealthy air. That means more high ozone levels are expected.
Ozone can become a respiratory irritant that forms when other pollutants mix.
That was also the nation's highest. Because of a number of high readings, Houston ended 1999 with the largest number of ozone violations in the nation, surpassing Los Angeles for the first time. Share your experience. Join or start this discussion Get personalized traffic reports.