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  • Ground-level ozone season has returned

    Apr 20, 2017 | Read More News
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    From now through September ground-level ozone increases in the air we breathe. In the layer far above the surface of the Earth, ozone helps protect our planet from solar radiation.

    ozoneHowever, when it forms at “nose-level” from various emissions reacting with the intense sunlight we have in the summer, ozone is harmful to our health. In Pima County, the largest single source of the emissions that form ozone is motor vehicles.
    The U.S. Environmental Protection Agency changed the National Ambient Air Quality Standard (NAAQS) for ozone in 2015 to make it more protective of public health. Because of this more stringent standard, ozone levels in Pima County are now very close to violating the health standard.
    How Close Are We to the EPA Ozone Standard?  The graph above shows historic levels of ground-level ozone at three different monitoring sites in Pima County.
    What Does Ozone Do To Our Health? According to EPA, ozone can have the follow health effects:
    • Make it more difficult to breathe deeply and vigorously.
    • Cause shortness of breath and pain when taking a deep breath.
    • Cause coughing and sore or scratchy throat.
    • Inflame and damage the airways.
    • Aggravate lung diseases such as asthma, emphysema, and chronic bronchitis.
    • Increase the frequency of asthma attacks.
    • Reduce lung function and harm lung tissue.
    • Make the lungs more susceptible to infection.
    • Continue to damage the lungs even when the symptoms have disappeared. Cause chronic obstructive pulmonary disease.
    • Ozone can cause the muscles in the airways to constrict, trapping air in the alveoli. This leads to wheezing and shortness of breath.  
    The health effects from unhealthy levels of ozone can lead to increased school and work absences, medication use, visits to doctors and emergency rooms, and hospital admissions.
    Who Is At Risk? People most at risk from breathing air containing unhealthy levels of ozone include people with asthma and other respiratory illnesses, children, older adults, and people who are active outdoors, especially outdoor workers.
    Who Determines if We Violate the Standard?  EPA decides if our region meets the new health standard by using an average of the most recent three years of ozone data from PDEQ monitors. Reducing ozone levels this summer could be key in keeping Pima County in attainment of the new EPA standard.
    What Can We Do To Keep Ozone Levels Down? There are many ways to reduce the pollutants that form ozone including: driving less and sharing rides, taking transit, biking, and walking when possible; combining errands into one trip; properly inflating tires, stopping at the click when refueling to avoid spills; refueling after 6 p.m.; limiting engine idling; and conserving electricity.
    How Can We Protect Ourselves If We Are Sensitive to Ozone? The Pima County Department of Environmental Quality (PDEQ) monitors for ozone at eight different monitoring sites throughout eastern Pima County. Real-time air quality data is provided on the PDEQ website and the public can receive air quality advisories via email or through Twitter @PimaDEQ.