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Residents’ Guide to Allegheny Co. Health Dept's '25 Network Monitoring Plan, How to Comment

If you follow our local air quality issues, then you likely already know the Allegheny County Health Department (ACHD) is our local air quality regulator and operates a network of air quality monitors.

What you might not know? Every year, ACHD is required to publish an air quality network monitoring plan providing a detailed description of how and where air pollution is monitored throughout the county.

These annual reports are mandated by the U.S. Environmental Protection Agency (EPA) and provide information such as the specific location of each monitoring station, monitoring methods, monitoring objectives, frequency of sampling, pollutants measured, and any planned changes to the network.

Right now, ACHD is seeking public comment on its 2025 Air Quality Network Monitoring Plan through 4:30 p.m. June. 14, so GASP wanted to give you all a breakdown of what’s new and notable in the report and how - and why - you should consider speaking out.

Where, What, When, and Why Does ACHD Monitor?

ACHD operates nine monitoring sites to meet the core objectives for all monitoring networks across the country. Those objections include:

  • Provide air pollution data to the general public in a timely manner;

  • Support compliance with ambient air quality standards and emissions strategy development; and

  • Support for air pollution research studies.

The complexity of the sites and the pollutants they measure vary by the sites’ objectives, with a site in Glassport monitoring a single pollutant – PM10 – and ACHD’s primary site in the City of Pittsburgh monitoring dozens of pollutants.

The monitoring site locations are established to meet certain objectives. For example, there is a near-road site along the Parkway East set up expressly to monitor pollutants from mobile sources and other sites that have changed over time to detect the highest levels or background levels of certain pollutants.

Many sites now monitor continuously as technology and internet connectivity have advanced, but not all pollutants can be monitored in real-time.

Ch-ch-ch-ch-changes (Que David Bowie)

In the 71-page plan, ACHD detailed monitoring additions since the publication of its 2024 Air Quality Network Monitoring Plan. They include…

Change 1: Lawrenceville Monitoring Station Will Be on the Move 

Yes, the Air Quality Program has relocated the Lawrenceville monitor from the Clack Health Center Complex to the Chateau neighborhood of the North Side as of November 2023 but it will need to be relocated. 

Here’s what’s going on:

In the 2023 Annual Monitoring Network Plan, ACHD proposed to move all the current monitoring operations at the Lawrenceville site to 836 Fulton Street in the Chateau neighborhood bordering Manchester - a move that received EPA Region 3 approval. 

However, because of potential interferences that could occur with the construction and operation of a new gas fueling station, ACHD is actively looking for alternative sites that could meet federal siting criteria to house the air monitoring operations currently at Lawrenceville.

Here’s what the air quality program said in the plan:

“Due to the sensitivity of the air quality instruments the expected air emissions from the gas fueling station, while small in quantity, could disproportionately affect the measurement of trace quantities of pollutants those instruments were designed to detect,” the Air Quality Program wrote.

ACHD continued:

“In other words, the proximity of the gas station to the instruments could show readings that are not representative of area-wide pollutant concentrations – particularly for volatile organic compounds and ozone precursors.”

The plan notes that ACHD is actively assessing other properties that could house the current Lawrenceville monitoring station while meeting rigorous federal siting criteria for monitoring sites.

Change 2: PM2.5, PM10 and PMCOARSE Monitoring Methods

All continuous PM2.5 monitors in the ACHD monitoring network now use either what’s known as a Teledyne T640 (PM2.5) or T640X (PM2.5, PM10, and PMCOARSE) instrument. 

ACHD elected to change to the new data alignment algorithm provided and recommended by the manufacturer on all the T640 and T640X instruments in use in the air monitoring network. And the EPA now allows for the data alignment algorithm to be used (under another new method code) retroactively for PM2.5 data submitted to AQS before the approved release of the algorithm in the summer of 2023. 

ACHD said this change has “lessened some of the bias that was seen in historical Teledyne PM2.5 FEM data compared to the PM2.5 FRM data.”

Change 3: The Addition of Continuous PM2.5 Monitors at South Fayette and Harrison

ACHD plans to proceed with the installation of continuous PM2.5 FEM monitors at all remaining PM2.5 SLAMS sites that do not currently have continuous PM2.5 coverage. The Department is awaiting the arrival of new environmental shelters to house the units. The PM2.5 FEM monitors will be candidates for designation as either a primary or collocated SLAMS PM2.5 monitor in the network.

Change 4: The Addition of a Hydrogen Sulfide Monitoring at Clairton Site 

ACHD plans to expand continuous hydrogen sulfide (H2S) surveillance by adding an H2S analyzer at the Clairton monitoring site after necessary upgrades and repairs are made to the station – including a new environmental shelter.

Change 5: The Addition of Wind Speed & Direction Sensors at Avalon and Clairton Sites

ACHD will install a meteorology tower at the new Avalon site to provide wind speed and wind direction data for the area. A similar meteorology installation will occur at the Clairton site.

Change 6: Moving Sulfur Dioxide Monitoring from South Fayette to Clairton Site

ACHD wants to relocate SO2 monitoring that was discontinued at the South Fayette site to the Clairton site after necessary upgrades and repairs are made to the station (the originally proposed design would not meet EPA siting criteria and a special enclosure must be modified and craned up to the roof of the site). 

GASP's Thoughts on This Year's Plan

GASP has mostly positive things to say about ACHD’s 2025 Air Network Monitoring Plan. 

“We are especially supportive of the department expanding hydrogen sulfide monitoring in the Mon Valley,” GASP Executive Director Patrick Campbell said. “More monitoring means more data and more data will hopefully lead to actionable insights and improved air quality for our frontline friends.”

For the uninitiated: Hydrogen sulfide (H2S) is a toxic gas with a rotten-egg odor that occurs both naturally (from sources such as swamps, manure pits, and oil, gas, and water wells) and as a result of industrial activity (including, most notably for our region, coke making). 

For years, residents in the Mon Valley and beyond have been subject to H2S concentrations high enough to exceed state limits and cause irritation to the eyes, nose, or throat and that have been linked to headaches, poor memory, tiredness, and balance problems according to the Agency for Toxic Substances and Disease Registry. Low concentrations of H2S may also cause difficulty in breathing for some asthmatics.

The culprit? According to two studies, it’s clear: U.S. Steel’s Clairton Coke Works operations. However, despite these studies and enforcement actions related to H2S, the Mon Valley is still pummeled by days-long periods of stench and exceedances. 

As of the date this blog was published, there have already been 51 days so far this year on which H2S concentrations exceeded Pennsylvania’s 24-hour limit. 

We hope the additional monitoring will ultimately lead to even more effective enforcement action and, hopefully, improved air quality and quality of life for Allegheny County residents.

GASP is also supportive of ACHD’s decision to move SO2 monitoring from South Fayette to the Clairton site.

“That’s a much more logical location for that monitoring given how much steelmaking operations like we see at the Mon Valley Works drives sulfur dioxide emissions,” Campbell said.

How and Why to Submit a Public Comment

If you’d like to echo our sentiments above or raise other concerns about how air quality is monitored in Allegheny County, submitting a formal public comment is simple.

Just email them to ACHD’s David D. Good at or mail them to: 301 39th Street, Building 7, Pittsburgh, PA 15201.

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