EPA Air Toxics Monitoring Project in Louisville

The United States Environmental Protection Agency (EPA) has been working with the Louisville Metro Air Pollution Control District (APCD) on projects in and around Rubbertown.

Rubbertown is an industrial area in Louisville located along the Ohio River. Due to a combination of factors, including the proximity of industrial sources of air pollutants to residential areas, it is the subject of air quality and environmental justice concerns.

Efforts have been made in the past to better understand and remedy the air pollution problems in Rubbertown. Conducted 2000-2001, the West Louisville Air Toxics Study showed that Louisville had unacceptably high levels of toxic chemicals in the air. In response to this study and other community input, the APCD implemented the Strategic Toxic Air Reduction (STAR) Program in 2005. Since the STAR program's inception, emissions of toxic chemicals have dropped almost 80 percent in Louisville/Jefferson County, but there is still work to be done. 

Air Toxics Monitoring with Next Generation Emissions Measurement (NGEM) Systems 

Funded by the EPA's Regional Applied Research Effort (RARE) program, the EPA installed prototype next generation emissions measurement (NGEM) systems to test in and around Rubbertown. The Air Pollution Control District assisted the EPA in siting and operating the various technologies being tested.

The project sought to deploy, test, and evaluate the NGEM systems and to use them to understand levels of select volatile organic compounds (VOCs) in the Rubbertown area. The goal was also to use the NGEM systems to learn more about the spatial impacts of industrial sources on the local community, and to better understand the effects of fugitive industrial emissions and odors.

site with varied air monitoring equipment from afar
The APCD's Air Monitoring site at Algonquin Pkwy with NGEM systems installed. 
Map of air monitoring area, featuring 10 small sites and two larger sites
A map of Rubbertown and the surrounding area with monitoring sites marked. 

To collect data for the study, researchers deployed a variety of NGEM systems. In the map above (right), you can see a basic map of where equipment was installed. Passive samplers were installed at 10 different sites throughout the community, with more extensive NGEM system testing at two sites, one of which was APCD's Air Monitoring Site at Algonquin Pkwy (above left).

NGEM systems installed at the Algonquin site (above left) as labeled:

  • S-Pods (1) are a low cost, solar-powered system that combines wind and air pollutant concentration measurements to detect emission plumes and help locate the source of emissions. S-Pods can also work in conjunction with a canister sampling system.  If an S-Pod detects high concentrations of VOCs, a sample of ambient air can be collected in an evacuated canister to be removed and analyzed in a laboratory. This can help provide a more detailed analysis of an emission event.  These grab canisters provide a useful “snapshot” but are not useful for determining long-terms averages of VOC concentrations.
  • Tricorntech MiTAP Field GC (2), ENMET eGC (3), and ACPD's auto-GC (5) are gas chromatographs (GCs). GCs are common tools used by laboratories to provide high performance analysis of ambient air samples and by industry for process control and safety functions.
    • Tricorntech MiTAP Field GC (2) is a mid-cost field GC that in our study detected concentrations of about sixteen individual VOCs.  The advantages of this system are that it can be outside a climate-controlled monitoring shelter and provides continuous, near-real time data.
    • ENMET eGC (3) is a low-cost auto-GC that is capable of measuring a few specific target compounds such as benzene or 1,3 butadiene in the field under near-ambient conditions.
    • APCD's auto-GC (5), located inside APCD’s Algonquin Rd Air Monitoring Station, is a high-cost field GC capable of detecting very low concentrations of many VOCs and provides continuous, near-real-time data.
  • Passive Samplers (4) use an adsorbent material where VOCs can accumulate over a 2-week period then are picked up and analyzed in a laboratory. They are useful because they do not require power and can be widely distributed to gain a better understanding of the spatial differences in pollutants throughout an area. Due to their two-week sampling period, they are not useful at measuring short-term emission events.

The field work completed in January 2020. Some conclusions of the study:

  • Passive samplers that were deployed were useful for understanding the spatial differences in concentrations of pollutants throughout the area, and in identifying chemical source signatures (chemicals associated with certain facilities). 
  • Passive samplers are not useful for capturing short-term or real-time "emissions events" or very low absolute concentrations for certain pollutants and compounds.
  • NGEM equipment installed at monitoring sites 1 and 8 were able to observe two elevated emissions events of 1,3-butadiene, one of which was connected to a known release from a Rubbertown facility.
  • Measurements indicated that key air toxics had generally decreased in comparison to the West Louisville Air Toxics study that concluded in 2005.
Odor Projects

In addition to concerns about health impacts from high concentrations of air toxics originating from Rubbertown industrial facilities, the neighborhoods surrounding this area have historically been impacted by frequent and strong odors, including those from the Commonwealth’s largest sewage treatment plant and combined sewer system. Odor emissions like these have a significant impact on quality of life and can be difficult for traditional air quality monitoring to detect.

In 2018, as one of the United States EPA's Regional-State Innovation Projects (RSIPs), a novel sensor system called an odor VOC Emissions Tracker (oVET) was used to detect odor-causing VOC emissions in Rubbertown. Learning more about the odors and what causes them ultimately helps find the sources of these emissions and will help inform mitigation strategies that will help improve the quality of life of impacted communities. 

The US EPA and Louisville APCD are also using their experiences from the other Rubbertown NGEM projects to create a new odor reporting app, the Odor Explore app. Odor Explore will allow affected members of the community to report odors and view a map of odor reports submitted by others. When reporting the odor, the app will walk residents through a few basic questions in order to find out more about the odor, including a new feature called an "odor wheel."

Wheel of odor sources and types

Odors can be difficult to describe, and often two different people will describe the same odor in very different ways. The odor wheel allows for a more detailed description of the odor while also providing common odors types and sources so that common wording will be utilized and sources of odor more easily determined. The contents of the wheel are unique to each area, matching known odor sources.

In conjunction with Odor Explore, US EPA and Louisville APCD are experimenting with Remotely Operated Canister Samplers (ROCS). These are VOC sampling canisters that can be remotely triggered by text messages or app data. For example, if APCD receives a few similar odor complaints on the Odor Explore app, it could trigger the ROCS systems to sample air quality in real time to find VOC emissions that may be the source of odor problems.

A map showing what is explained in text, the way the odor app will work
(From April 20, 2021 EPA Presentation to West Jefferson County Community Task Force)

The ROCS systems and the Odor Explore app are both currently in development. The Odor Explore app is currently in pilot testing and it is not available in app stores. 

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