Monitoring Louisville's Air Quality
The Air Monitoring section of the Air Pollution Control District annually collects tens of millions of data points on Louisville’s air quality, using five different sites throughout the city.
Air pollution levels are monitored through a variety of instruments, ranging from teflon filters that collect fine particle pollution to advanced instruments that can measure small levels of air toxics in real-time. Collected data are rigorously analyzed, quality assured, and then reported to the United States Environmental Protection Agency (EPA), National Air and Radiation Environmental Laboratory (NAREL), and other agencies.
The data that the monitoring team collects is used for real-time air monitoring services like Louisville Air Watch, to determine Louisville's compliance with federal air quality standards, to educate the public on local air quality, and to inform federal, state, and local policy making.
APCD’s air monitoring section is a national leader in utilizing novel & advanced technology to learn more about what’s in Louisville’s air; including their use of machines called “auto-GCs” at our Algonquin & Cannons Lane monitoring site to measure toxic air pollution in near-real time. Find more below on the equipment used and the data collected.
National Ambient Air Quality Standards (NAAQS)
Through the Clean Air Act, the EPA has determined six "criteria" pollutants that have been deemed harmful to public health and the environment. The monitored levels of these pollutants are used to determine the Air Quality Index (AQI) as well as our area’s attainment with National Ambient Air Quality Standards. The pollutants are: ground-level ozone (O3), Particle Pollution (PM10 and PM2.5), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and lead* (Pb).
*In 2016, the EPA authorized the APCD to discontinue active monitoring of airborne lead (Pb) because levels are far below the NAAQS and are not expected to increase at the present time.
An air toxic is any air pollutant that is not a “criteria pollutant” for the National Ambient Air Quality Standards, but may reasonably be anticipated to cause serious chronic or acute health effects in humans at certain levels. Louisville has a difficult history with air toxic pollution, most notably in the areas surrounding the Rubbertown industrial complex.
The APCD has now added equipment capable of monitoring for air toxics at two of its air monitoring sites, 2730 Cannons Lane and 4201 Algonquin Parkway. This new technology allows the District to collect data in near real time on concentrations of a variety of air toxics, which have traditionally been much more difficult and expensive to monitor for. You can find our monthly air monitoring reports on our air quality data page, and you can follow air toxics concentrations in real time on the Cannons Lane and Algonquin Parkway pages on Louisville Air Watch.
The APCD has published a report titled Air Toxics Monitoring Report July 2020 - June 2021 to summarize the progress of the project and the first year of quality-assured data that was collected.
The APCD monitors radioactivity in Louisville. EPA’s RadNet is a national network of monitoring stations that regularly collect air, precipitation, drinking water, and milk samples for analysis of radioactivity. The National Air and Radiation Environmental Laboratory (NAREL) oversees RadNet monitoring. The APCD supports RadNet by collecting and processing air samples and providing NAREL real time data 24 hours a day, seven days a week. The radiation monitors use an alpha and beta counting system plus filters to measure isotopes of plutonium and uranium (Pu-238, Pu-239, Pu-240, U-234, U-235, U-238).
Meteorological data such as wind speed and direction, temperature, rainfall, barometric pressure, and humidity are collected to assist in making air quality forecasts and further analysis of air pollution data and episodes.