Source:  NCDENR, 3/1/19

Today marks the start of the 2019 Ozone Season, which runs from March 1 through October 31.  The Division of Air Quality, along with its local partner programs, will issue daily ozone forecasts for seven North Carolina Metropolitan areas throughout the ozone season.

The daily ozone forecasts are available on the Division of Air Quality website as well as on the NC Air Quality Forecast Center Facebook pageand Twitter accounts.  Ozone forecasts are issued for the Asheville, Charlotte, Fayetteville, Hickory, Triad, Triangle and Rocky Mount metropolitan areas at 3 p.m. every day for the next day.

Ozone forms in the air when nitrogen oxides, or NOx, react with hydrocarbons on warm, sunny days with little wind.  Here in North Carolina, ground-level ozone formation continues to decline due to steady reductions in emissions from the primary sources of NOx: power plants, industry and motor vehicles. The entire state continues to be in compliance with the more stringent federal ozone standard adopted in 2015.

For those interested in tracking compliance over the course of the ozone season, DAQ has introduced a new map-based Ozone Design Value Predictor tool.  Ozone is measured in rolling 8-hour averages at monitors each day.  The fourth highest daily maximum each year is averaged for three years to determine the current design value.  To meet the federal standard, the design value must be at or below 70 parts per billion.  The tool has been well-received by air quality professionals across the country as it helps track ozone design values and whether an area is likely to violate the standard.

Historical summaries for ozone and other air pollutants in the state can be found in the Air Quality Trends in North Carolina report and on the Air Quality website https://deq.nc.gov/airquality