March 1 marks the beginning of the 2021 ozone season, as state and local environmental agencies renew their daily air quality forecasts for ozone across North Carolina. From now through October 31, the daily air quality forecasts from the North Carolina Division of Air Quality (DAQ) will include statewide forecasts for ozone as well as our year-round forecasts for fine particle pollution.
Ozone forms in the air when nitrogen oxides (NOx) react with hydrocarbons on warm, sunny days with little wind. While it was once North Carolina's most widespread air quality concern and contributor to breathing problems, ozone continues to decline due to steady reductions in emissions from its primary air pollution sources: power plants, industry and motor vehicles. North Carolina has been in statewide attainment with the federal ozone standards since 2017. EPA designated North Carolina as attaining the 2015 ozone standard statewide.
The county-based forecasting launched in 2020, which replaced our previous system of regional forecasting. The new forecast process gives users up-to-date and localized forecasting for 91 North Carolina counties and two Ridge Top zones, including the next day's forecast. Our colleagues at the Forsyth County Office of Environmental Assistance and Protection forecast the air quality for the greater Triad region, including the cities of Winston-Salem and Greensboro.
DAQ also developed an Ozone Design Value Predictor Tool, a web-based mapping tool that displays maximum 8-hour ozone and Design Value information using current year ozone data for all ozone monitors in the U.S. The tool provides an up-to-date snapshot of ozone monitor attainment status based on current year ozone data.
The new process will continue to monitor and forecast ozone and particulate matter, or PM2.5, via the air quality index (AQI), along with the corresponding AQI color codes to help North Carolinians plan their outdoor activities. Next-day and extended products are issued by 3 p.m. with a morning update by 10 a.m. The forecast is automatically saved every 15 minutes, and the public may also view the air quality forecast on on DAQ’s website, Twitter feed, Facebook page or the AirNow site.