Several of Texas’s biggest cities, including Houston, Dallas, and San Antonio, have been blanketed by multiple ozone action day s this week. Issued by the state’s environmental agency and relayed by the National Weather Service, these warnings inform residents that air pollution in a given area may reach potentially harmful levels. Newsweek spoke with experts about why many of the Lone Star State’s largest cities have been under so many of the alerts this week. The Texas Commission on