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  • 2019 Ozone Season "In-the-Books"

    Oct 01, 2019 | Read More News
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    The 2019 ozone season in Pima County has ended with one day when air quality exceeded the U.S. Environmental Protection Agency's health standard for ground-level ozone. In 2018, there were five days with exceedances, which triggered this region's first violation of the EPA's ozone standard. "This year's levels were positive outcomes for all the people who areOzone Exceedances affected by ozone and for our expanded educational outreach this summer," said Beth Gorman, Senior Program Manager for the Pima County Department of Envrionmental Quality. "We thank everyone who made the effort to drive less, idles less, and share rides more to reduce the vehicle emissions that contribute to ozone," said Gorman. Other factors, such as weather conditions and lack of wildfire smoke in the area, also may have played a part in lower levels of ozone this summer.

    The consequences of the 2018 ozone standard violation have yet to be determined by EPA. It is likely that during the next review of the ozone standard, scheduled for 2020, the EPA will decide if a portion of eastern Pima County should be designated as "non-attainment". If that happens, some new and existing businesses that wish to expand would be required to offset any emissions the business creates that contribute to ozone. "The fact that we experienced only one exceedance of the ozone standard this season could improve the chances of Pima County remaining in attainment status," said Gorman.

    The ozone season in Pima County runs from April through September, when intense solar radiation and warm temperatures enable the photochemical reaction that creates the harmful air pollutant. Ground-level ozone differs from the naturally occurring and protective stratospheric ozone layer in that it is a product of emissions at "nose level" that can harm our health. Ozone can cause chest pain, coughing, shortness of breath, throat irritation and can worsen chronic respiratory diseases, such as asthma. Many individuals in Pima County are at risk when ground-level ozone is in the unhealthy range, including people with respiratory disease, children under the age of 18, adults 65 and older, and people who exercise and work outside. 

    Numerous actions can be taken to reduce ozone including driving and idling less, sharing rides or taking transit, refueling in the evening, avoiding the use of gasoline-powered lawn and gardening equipment, conserving electricity, using low-VOC paints, reducing the use of household chemicals such as charcoal lighter fluid and planting low VOC-emitting trees. More information on ozone is available through PDEQ's Information, Education and Public Outreach section.