LaPlace, Louisiana - Air Monitoring

About the monitoring

EPA began monitoring for chloroprene in the neighborhoods near the Denka Performance Elastomers - Pontchartrain Facility (formerly the DuPont Neoprene Facility, Pontchartrain Works) in the Spring of 2016. The purpose of the monitoring is to collect air samples to assist in EPA's assessment of the long-term ambient chloroprene concentrations and to gauge the potential risks to the community from chloroprene emissions. EPA is primarily concerned about the potential for long-term risk in the community and will be assessing that risk as more results become available. To keep the community informed during the monitoring period, we are providing individual sample results on this website throughout the monitoring period. 

EPA initially collected samples every third day at  six monitoring sites in LaPlace. Beginning on March 1, 2019 the sample collection frequency became every sixth day at the six monitoring sites. The sample collection duration is 24 consecutive hours. For quality purposes, EPA collects one additional (collocated) sample at one of the six monitoring sites. The collocated sample location changes and is selected based on the predicted direction of the winds for the day of sampling. More information can be found in the  Air Monitoring Plan.

During the week of March 9-13, 2020, the EPA deployed an air monitoring program around the Denka Facility. The continuous monitoring program was established to provide a better understanding of the frequency and magnitude of chloroprene emission spikes and may help identify possible actions to further reduce chloroprene in the community. 

 This monitoring program used six SPod monitoring stations that consisted of a stationary photoionization detector (PID), a meteorological station to record weather data, and one or more summa canisters for sampling. The PID continuously measures for total volatile organic compounds (VOC) in the ambient air and, when VOC concentrations reach a certain threshold, a canister will collect a sample that will be measured for chloroprene in a laboratory. The EPA operated the continuous monitoring system through August 2023. The continuous monitors were located in close proximity to the initial air monitors that were operated in the community between May 2016 and September 2020;

More information can be found in the materials below:

Deputy Regional Administrator David Gray’s presentation in LaPlace on February, 11, 2020.

Quality Assurance Project Plan for SPod Monitoring (March 6, 2020)

About the Data

Every sixth day monitoring program

The monitoring results tables show the levels of chloroprene in the air samples collected at each monitoring location every six days, and that air monitoring data is available here.

The continuous monitoring program

The monitoring results tables for the continuous monitoring program show the levels of chloroprene in the air samples collected at the monitoring location where the continuously measured total VOCs in the ambient air reached a certain trigger-level and initiated a 24-hour average canister sample.

The continuous monitoring program was designed with two monitoring phases. The Initial Phase was planned to evaluate sampling equipment performance and to establish when each continuous monitor would collect a 24-hour average canister sample. During the Initial Phase of the program, at each monitoring location, when the monitor detected a total VOC measurement above a set threshold, at an unchanging static trigger-level, the collection of a 24-hour average canister sample was triggered.   During the Initial Phase of the program, 24-hour average canister samples were collected.  The monitoring results table include the chloroprene levels from all air canister samples collected during the Initial Phase since the program was deployed the week of March 9-13, 2020. 

 The continuous monitoring program entered the Operational Phase (second phase) of the program in September of 2020. During this phase of the program, the EPA implemented a dynamic triggering approach for collection of air canister samples. This approach allowed the VOC trigger-level to change over time, as meteorological patterns naturally change at each sampling location throughout the day. The implementation of a changing dynamic trigger-level allowed the continuous monitors to trigger the collection of 24-hour average canister samples that might have been missed using an unchanging static trigger-level. Chloroprene levels from the canister samples collected by the continuous monitoring program is available here.

On August 16, 2023 the EPA concluded the continuous monitoring program using the six SPod monitoring stations, having collected over 748 air samples from March 10, 2020 through August 16, 2023.