What’s in the Proposed 2025 Ambient Air Monitoring Network Plan for Kentucky?

Each year, the Kentucky Energy and Environment Cabinet releases its annual plan detailing how ambient air quality will be monitored across the Commonwealth. The Proposed 2025 Ambient Air Monitoring Network Plan is now available for public review and comment until June 20, 2025. The plan offers insight into how Kentucky monitors air quality for compliance with National Ambient Air Quality Standards (NAAQS). While this year’s plan reflects continuity, it also includes several technical and logistical updates worth noting.

Ambient Air Monitoring in Kentucky

Ambient air quality monitoring in Kentucky is collective by three entities: the Kentucky Division for Air Quality (KDAQ), the Louisville Metro Air Pollution Control District (LMAPCD), and the National Park Service. These organizations oversee a network of 30 monitoring sites spread across 25 counties, operating 103 instruments in total, including 7 meteorological stations. The monitoring network collects ambient concentration data for NAAQS pollutants including ozone (O₃), particulate matter (PM_2.5 and PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and lead (Pb). The network also includes specialized monitoring, such as speciation analysis of particulate matter, continuous volatile organic compound (VOC) sampling, and radiation monitoring through RadNet stations. At select specialized monitoring stations, KDAQ and LAMPCD collect speciated data for regulated toxic air contaminants (TAC), polycyclic aromatic hydrocarbons (PAH), and carbonyls. Air quality data collected is quality assured and submitted to the U.S. Environmental Protection Agency (U.S. EPA) Air Quality System (AQS). The data submitted to U.S. EPA is used to designate areas under the NAAQS, evaluate trends for long-term policy planning, and inform the public through tools like the Air Quality Index (AQI).

What is New or Changed

No changes are proposed for the number of monitoring stations in KDAQ’s network. KDAQ will continue to operate 67 instruments across 24 monitoring sites and one meteorological station. KDAQ is reapplying for previously approved monitoring waivers for Somerset (21-199-0003) for siting that may be impacted by traffic for temporary FEMA housing and Hazard (21-193-0003) for PM_2.5 distance from a roadway. Those original waivers were granted in 2023 by U.S. EPA as a precaution. Additionally, the Memorandum of Agreement (MOA) with neighboring states has been updated to ensure ongoing coordination on cross-border air quality matters.

Under the plan, KDAQ will relocate the Hopkinsville (21-047-0006) monitoring site for PM_2.5 and seasonal ozone to a new location at Pennyrile Forest (21-047-0007), prompted by increased traffic along a nearby gravel road. The new site is set to begin operations on July 1, 2025, and will carry over the same equipment and monitoring objectives. This change should allow for better data quality while maintaining regional monitoring requirements in the Clarksville, TN-KY area.

For monitoring stations in Jefferson County, KY, LMAPCD is proposing no changes to the ambient air monitoring network. Hourly air toxics monitoring continues at the Algonquin Parkway site near Rubbertown using an automated gas chromatograph (Auto-GC) to collect data on selected VOCs. Routine data collection of a subset of VOCs began in July 2020, and the Auto-GC system has since been upgraded for improved performance and integration with LMAPCD’s central data collection system and database. Limitations remain in data management and detecting all target compounds. Data quality has contributed to reporting delays.

LMAPCD also planned a 12-month air monitoring project in Rubbertown starting in early 2025 under the U.S. EPA’s Environmental Justice Government-to-Government Grant Program. The project aimed to measure VOCs, formaldehyde, and speciated metals from particulate samples. In March 2025, the U.S. EPA terminated funding, which LMAPCD is disputing under 2 CFR 1500.15.

Public Input and What Comes Next

The plan is now open for a 30-day public comment period from May 21, 2025, to June 20, 2025. You can review the full 2025 Ambient Air Monitoring Network Plan and submit public comments through the Division for Air Quality’s website at the link below:

https://eec.ky.gov/Environmental-Protection/Air/Pages/Public-Notices.aspx

Even though no major network changes are currently proposed, it’s important to note that adjustments may still happen during the year. Any such changes, whether adding a new monitor or relocating a station, will require U.S. EPA approval and another public comment opportunity.

ALL4 will continue to track policy updates, procedural regulatory actions, and rulemaking in the Commonwealth of Kentucky for all matters regulated under the Clean Air Act. If you have any questions on how this plan could impact your organization, please contact Dylan Ernst at dernst@all4inc.com or Stewart McCollam at smccollam@all4inc.com.