Ozone readings in Perry County stayed low this summer

With only 10 days left in ozone season, ground-level ozone readings have remained consistently below allowable standard limits.

So far this year, only one reading at Farrar, Missouri, in Perry County has exceeded the allowable limit. That reading was taken June 9. Hot, humid weather can raise monitor readings.

A Perryville, Missouri, air-quality committee tracks daily readings taken by the Missouri Department of Natural Resources.

The department collects data from air monitors to see whether the state's air quality meets the Environmental Protection Agency's National Ambient Air Quality Standards, according to dnr.mo.gov.

If the ozone standard for an area is violated, the county is designated a non-attainment area, and actions must be taken to reduce emissions contributing to the formation of ground-level ozone, or smog.

Ozone season runs from April 1 to Oct. 31.

On Oct. 1, the EPA released a new air-quality standard. The allowable limit has been changed to 70 parts per billion. The EPA's previous allowable limit for ground-level ozone was 75 ppb, as established in 2008.

The new standard is in place as of Oct. 1, but no enforcement or implementation action will be taken until non-attainment areas are identified, Southeast Missouri Regional Planning Commission deputy director David Grimes said in an email.

"The Missouri Department of Natural Resources has a year to prepare their recommendations for non-attainment areas," Grimes wrote. The EPA then has another year to review and approve or disapprove those recommendations.

"As it stands now, as long as next year's readings remain below 79 for the Perry County monitor and 81 for the Ste. Genevieve County monitor, we should retain our 'unclassifiable/attainment' designation for both monitors," Grimes wrote.

kwebster@semissourian.com

(573) 388-3646

Pertinent address:

Farrar, MO