2024 PM2.5 Annual Standard

In February 2024, EPA announced it will tighten the annual health-based National Ambient Air Quality Standard for fine particulate matter (PM_2.5) from 12.0 µg/m³ to 9.0 µg/m³.

This change is being made after a review of the available scientific evidence, technical information, and advice of an independent scientific panel. EPA says lowering the standard will result in significant public health benefits, advance the economy and improve quality of life. According to EPA, in 2032, the stronger standard will avoid 4,500 premature deaths, 800,000 cases of asthma symptoms, and 290,000 lost workdays, with $46 billion in public health savings. PM2.5 is a pollutant of great concern to people with asthma or lung disease and to already overburdened and vulnerable populations, including many communities of color and low-income communities.

EPA decided to not change the following standards at this time:

• The secondary (welfare-based) annual PM_2.5 standard (15.0 µg/m³)
• The primary and secondary 24-hour PM_2.5 standard (35 µg/m³)
• The primary and secondary 24-hour PM₁₀ standard (150 µg/m³)

North Carolina Status

North Carolinians are breathing the cleanest air in decades. North Carolina has seen a 49% decline in PM_2.5 emissions between 1990 and 2020, due to efforts of state leaders, regulatory agencies, electric utilities, industry and the public. All areas of North Carolina are in attainment with the previous PM_2.5 annual standard (12.0 µg/m³). North Carolina will continue working with stakeholders to ensure the state’s air quality will meet the new PM_2.5 standard.

Based on the latest certified monitoring data from 2020-2022, all areas of North Carolina would have been meeting the new annual PM_2.5 standard (9.0 µg/m³) during this time.

Preliminary data from 2023, still undergoing quality assurance review, indicates the majority of monitoring sites in North Carolina are meeting the new standard. However, the preliminary 2023 data shows four monitoring sites in the state may be slightly above the new standard, due to influences of Canadian wildfire smoke. These sites, as seen in the map below, are in Mecklenburg, Wake, Forsyth and Davidson counties. Without the influence from Canadian wildfire smoke, none of North Carolina's monitors would have exceeded the new standard in 2023. 

Designation Process

When a new air quality standard is announced, the designation process as defined by federal rule takes two years to complete.  Areas meeting the new standard will be designated as “attainment” and areas not meeting the standard are designated as “nonattainment.”  The process will involve state input and public comment opportunities. 

By February 7, 2025, the state has to submit to EPA designation recommendations based on five factors including current monitoring data (2021-2023).  EPA will review these recommendations, look at the current monitoring data available at that time (2022-2024) then make the final designations by February 6, 2026.

EPA has said it will consider impacts from wildfire smoke when making designations if the state submits an exceptional event demonstration for the dates impacted by wildfire smoke for all affected monitors. EPA’s Exceptional Events rule establishes criteria and procedures for use in determining if air quality monitoring data has been influenced by exceptional events such as wildfire smoke and fireworks. DEQ is reviewing its monitoring data from 2023 in preparation for submitting an Exceptional Events demonstration to EPA for monitoring sites above 9.0 µg/m3. 

Attainment/nonattainment designations will likely be based on PM_2.5 monitoring data collected from 2022-2024. Until this data is collected and reviewed, it is too early to know which, if any, areas of North Carolina may be in nonattainment with the new standard. Keeping PM_2.5 levels low in 2024 will be critical for attaining the new standard.

Air Quality Index

The revised PM_2.5 annual standard also adjusts Air Quality Index (AQI) levels. Once the changes become effective later this year, there will be more stringent targets for Code Green “good" days. Expect to see more Code Yellow “moderate" days annually while air quality in our area continues to improve. The below table has information on the new breakpoints for Code Green, Code Yellow and other AQI color codes. 

Air quality forecasts are available every day for all 100 North Carolina counties online from the Air Quality Portal.

Take Action to reduce harmful PM2.5

There are many ways North Carolinians can help reduce PM_2.5:

• Never burn trash or other man-made materials.
• Burn dry, seasoned wood to reduce smoke from fire pits or woodstoves.
• Reduce driving: Telework, carpool, ride your bike, or ride public transit, and bring your lunch to work rather than driving to lunch.
• Keep vehicles in good working condition.
• Use electric or hand-powered lawn equipment or reduce use of gasoline-powered lawn equipment.
• Attend community-wide firework displays instead of having your own fireworks.
• When making an outdoor grill purchase, opt for propane, gas, or electric rather than charcoal or wood. 

Ongoing efforts

DEQ continues to work with stakeholders and our partners to achieve reductions in PM_2.5 emissions. Efforts include:

• Supporting the adoption of clean and all-electric cars and trucks through our Mobile Sources Emissions Reductions grant and Volkswagen Settlement grant programs.
• Ensuring compliance of regulated sources of air pollution.
• Responding to reports of dust, smoke and vehicle emissions that violate air quality rules.
• Educating the public on the impacts and sources of air pollution.