Ozone (1 of 2) (IMAGE) University of Houston Caption This graph shows days in which ozone levels in Aldine exceeded EPA standards during a one-hour period over the past 23 years (blue line), contrasted with number of hours of southerly wind flow (red). Credit University of Houston Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.