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  • Ground-Level Ozone Season is Here

    Apr 15, 2016 | Read More News
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    Ozone LevelsFrom now through September ground-level ozone values start to increase in the air we breathe. In the layer far above the surface of the Earth, ozone helps protect our planet from solar radiation. However, when it forms at “nose-level” from various emissions reacting with intense sunlight, ozone is harmful to our health. In Pima County, the largest single source of the emissions that form ozone are motor vehicles.

    Recent health studies indicate that ground-level ozone is more harmful than previously thought, so the U.S. Environmental Protection Agency changed the National Ambient Air Quality Standard (NAAQS) for ozone to make it more protective of public health. The NAAQS for ozone was changed from 75 parts per billion (ppb) to 70 ppb in October of 2015. As a result of this more stringent health standard, ozone levels in Pima County are now very close to violating the new standard. 
    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.

    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. 

    People most at risk from breathing air containing unhealthy levels of ozone include people with asthma, children, older adults, and people who are active outdoors, especially outdoor workers. 

    EPA will decide if our region meets the new health standard in October of 2017, 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. 

    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 5 p.m.; limiting engine idling; and conserving electricity.

    The Pima County Department of Environmental Quality (PDEQ) monitors for ozone at eight different monitoring sites throughout eastern Pima County. Current air quality data is provided real-time on our website at www.pima.gov/deq and the public can receive air quality advisories via email by signing up on our website or through Twitter @PimaDEQ


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