v>EPA United States Environmental Protection Agency EPA Proposes 2015 Ozone Standard Clean Data Determination for the Detroit Area Southeast Michigan February 2023 For More Information To download a copy of the proposed rulemaking, visit: https://www.federalregister.gOv/d/2 023-02284 The proposed and final actions as well as other background information are available electronically at http: //www. re gulations. gov. Docket ID No. EPA-R05-OAR- 2023-0058 Additional documents about the plan can be found on the following website: https://www.epa.gov/mi/clean- data-dctermination-2015-ozone- air-quality-standard Contact EPA For more information about the plan contact: Eric Svingen Environmental Engineer (312) 353-4489 svingen.eric@epa.gov To review EPA's environmental justice policies and mandates, please visit: https://www.epa. gov/environmentali ustice/learn-about-environmental- iustice You may call EPA's Chicago office toll-freest 800-621-8431, 8:00 a.m. - 4:30 p.m. weekdays. 4/|V . i I 7036 JT / L —] « / Lapeer r~ Flmt V if (jOn08M J / Sarnia Clinton Shiawassee St. Clair | I Wflterford . J _ ,. , Macomb Oakland r. • i ... _ ?rlinq Heiqr •< Ingham Livingston Jackson .7. ,r ¦ Detroit Washtenaw Wayne t t I f Leamington illsdale t \ Adrian Monroe \ Lenawee s V % i . X.. Toledo ~ Map of counties included in the Detroit 2015 Ozone Non attainment Area EPA is proposing a clean data determination for the Detroit 8-hour ozone nonattainment area, concluding that the area has monitored attainment of the 2015 8-hour National Ambient Air Quality Standard (NAAQS) for ozone, based upon certified 2020-2022 ozone data. The Detroit area, including Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, and Wayne counties, has a 2020-2022 ozone design value of 0.070 parts per million (ppm), which is the threshold for an attainment determination. This determination is based on an analysis from the Michigan Department of Environment, Great Lakes and Energy (EGLE) that high ozone values in June 2022 were caused by wildfires. EPA is also taking comment on the state's analysis. EGLE'S analysis relies on meteorological data, modeling of air mass trajectories, comparisons to historical data, and measurements of brown carbon and black carbon, or soot. Considered together, the analysis concludes that high smog values measured at an air monitor in Wayne County on June 24 and 25, 2022 were caused by Canadian wildfires. Under EPA rules, wildfire impacts may be excluded when calculating attainment of the smog standard. The air quality data now shows that the Detroit area meets the federal smog standard. Air quality that shows attainment of the standard is one of the requirements for areas to receive formal air quality ""attainment'' status under the Clean Air Act. ------- Public Comments EPA is holding a 31-day public comment period on this proposed rule. EPA will provide responses to any adverse comments received in the final rule. Background The Clean Data Policy states that EPA can waive certain requirements of the Clean Air Act for designated nonattainment areas where air monitoring data shows the relevant NAAQS have been achieved. This is called a clean data determination and applies as long as air quality continues to meet the standard. Suspended planning elements include: • reasonable further progress requirements; • attainment demonstrations; • reasonably available control measures; • contingency measures; and • other state planning requirements related to attainment of the NAAQS. The clean data determination does not suspend requirements that are independent of helping the area achieve attainment, such as requirements to submit an emissions inventory and nonattainment new source review requirements. Finalizing this action does not constitute a redesignation to attainment under the CAA. The state would still have to meet the statutory requirements for redesignation in order to be redesignated to attainment. If, after finalization of this action but prior to redesignation, the area monitors a violation of the ozone NAAQS, the area would again be subject to the requirement to submit the pertinent attainment plan elements or SIP revisions On October 1, 2015, EPA strengthened the level of the NAAQS for ozone from 0.075 ppm to a more protective 0.070 ppm. As shown in the graph below, ozone in the Detroit area has declined significantly over the last 20 years. The most recent design value1, based on 2020-2022 data, is attaining the standard with a design value of 0.070 ppm. EPA is proposing this Clean Data Determination based on 2020-2022 data. Detroit Ozone NAA Design Value Trends, 2002-2022 0.100 0.065 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 Caption: The chart above shows the decreasing trend of ozone design values (in parts per million) for the Detroit area from 2002 through 2022, showing that the area is currently meeting the 2015 ozone National Ambient Air Quality Standard. ------- |