Our Grade: D In the Central Maryland region there were six times during 2014 when ozone levels exceeded the standard. The Baltimore metropolitan region is a non-attainment area under the EPA's 2008 standard for 8-hour ozone levels.
Definition: This indicator measures the number of times during 2014 when measured levels of ozone exceeded the U.S. Environmental Protection Agency's standard.
Reason: This is an indicator of whether our transportation system is keeping you and your environment healthy. Ozone is one of four pollutants the U.S. EPA lists as transportation-related. Ozone in the upper atmosphere is beneficial because it shields the earth from the sun's ultraviolet radiation, but high concentrations of it at ground level are a major environmental and health concern. Emissions from cars, trucks, buses and other vehicles help cause ground-level ozone to form. Breathing ozone can scar your lung tissue, reduce your lung function, and trigger chest pain, coughing, and congestion. It can worsen asthma, bronchitis and emphysema.
Who's Doing It Better?: Minneapolis. There were no measures of ozone levels in the air in the Minneapolis - St. Paul region during 2014 that exceeded the EPA's standard.