Real-Time Air Monitoring

Real-time (short-term) air monitoring occurs during dredging and CDF operations to ensure activities are conducted safely to avoid negative impacts consistent with USEPA guidance.

Note: In July 2021, USACE began the Phase 2 dike project to expand the CDF exterior dikes by 11 feet to maintain sufficient storage capacity for the intended project life, consistent with the original project authorization and plan. Dredging is not being performed while construction is underway. As a result, PID monitoring and turbidity monitoring are on hold. Real-time air monitoring continues in temporary locations off dike at onsite northeast and southeast stations using the M1 and M2 monitors (AM1 and AM2). The M3 and M4 monitors are not operating during dike expansion. Ambient air monitoring continues in one southwest location off dike (CON-SOUTH) and at the school. Dredging activities are anticipated to resume in 2024. More information »

map — Real-time air monitoring locations. Particulate monitors collect data at each location. PID monitoring takes place daily at the dock area. [Source: USACE]

Real-time air monitoring data is collected at four monitoring stations around the perimeter of the CDF cells and at the off-loading barge. This data is used for the management of the daily operation of the CDF. Air monitoring along the perimeter of the CDF measures emissions of particulate matter (PM). Each perimeter air monitoring station consists of a hybrid ambient particulate monitor for measuring PM₁₀ and PM_2.5. Air monitoring at the dock area is also performed daily during dredging using a photo-ionization detector (PID).

Purpose of Real-Time Air Monitoring

The primary goals of real-time air monitoring are to:

Monitor and verify the air quality at the site during dredging and CDF operations
Manage site operations to avoid negative impacts of potential air emissions
Ensure that work is conducted safely and effectively
Ensure that CDF operations are consistent with USEPA guidance for air quality impacts and IDEM regulations for air quality

Types of Monitoring

Particulate Matter (PM)

Each perimeter air monitoring station includes a hybrid ambient particulate monitor for measuring PM₁₀ and PM_2.5 (dust). Data is collected every 15-minutes during operations.

Particulates Data

Dock Area Photoionization Detector (PID) VOC Monitoring

photo of PID — Photo-ionization detector (PID) [Source: USACE]

In addition to perimeter air monitoring, air monitoring at the dock area is performed daily during dredging using a photo-ionization detector (PID). This monitoring provides data on the effects of sediment activity at the barge on emission levels for worker and community safety. PID monitoring takes place daily prior-to and during dredging for VOCs.

PID Monitoring Data

Naphthalene (Historical)

photo of monitor — UV-DOAS monitor [Source: USACE]

From 2012 to 2021, each perimeter air monitoring station included a two-part open-path ultraviolet differential optical absorption spectrometer (UV-DOAS) that measured naphthalene. These monitors collected data along an open path between two points. Naphthalene monitoring was discontinued in 2021. Historical data is available.

Naphthalene Data

Meterological Station

A meteorological station at the CDF site was installed by the U.S. Geological Survey (USGS) in 2012, and is used to differentiate between upwind (background) and downwind (background plus CDF component) data. Background levels were determined by historical air quality statistics and are updated periodically based on upwind data. Action levels are based solely on the CDF component of the air quality results.