Air quality monitors moved to collect more accurate data

The Elgin Courier: December 19, 2018

In order to better measure the amount of ozone in the air in the Greater Austin area, the Capital Area Council of Governments is moving a handful of its ozone monitoring stations, including two of its stations in Bastrop County.

The Capital Area Council of Governments (CAPCOG) is a coalition of municipal and county governments from ten Central Texas counties that work together on issues in the region. Within CAPCOG is the Clean Air Coalition (CAC), a group that works on reducing air pollution and improving air quality in the region.

Ozone is a gas which is considered an air pollutant at ground level, often created when heat and sunlight interacts with nitrogen oxides emitted by vehicles, power plants and other sources. It can cause respiratory issues for people and can be especially harmful to sensitive groups such as children and the elderly.

In 2015, the Environmental Protection Agency set a standard for 70 parts per billion of ozone in the ambient air; the Austin-Round Rock Metropolitan Statistical Area (MSA), which is a part of CAPCOG’s region, measures 69 parts per billion as its design value, or an average based on measurements from the past three years. If the value rises above 70 parts per billion, the area would be designated “nonattainment” for the EPA standards and would face regulations and economic costs by preventing business expansion, delaying infrastructure improvements and losing federal funding.

Although the measurements used to find this value are from ozone monitoring stations in Travis County run by the Texas Commission on Environmental Quality (TCEQ), the CAPCOG stations are important for the organization to understand the levels of ground-layer ozone in other counties and throughout the region, said Andrew Hoekzema, CAPCOG assistant director of regional planning and services.

“CAPCOG’s monitoring is important to providing a more complete picture of ground-level ozone levels throughout the region than what can be achieved with just the two monitors operated by TCEQ in Travis County,” he said by email.

This map from CAPCOG’s Ozone Monitoring Networks Review Report for 2019-2023 shows the proposed relocations of three ozone monitoring stations. The CAPCOG station in Travis County was proposed to be moved east, the Fayette County will be moved to Elgin and the current sole Bastrop County monitor will be moved from McKinney Roughs Nature Park to within the City of Bastrop.

One of the stations, located in McKinney Roughs Nature Park, is being moved because it is located near a lot of trees. Trees absorb ozone, Hoekzema said, so trees surrounding a monitoring station would artificially lower the reading. Trees can provide surfaces to react with or absorb nitrogen oxides and ozone, so the EPA requires monitoring agencies to take into account nearby trees on ozone monitoring sites.

“If you are collecting ozone measurements right next to trees, you’ll get noticeably lower ozone readings than you would get if you were collecting data even 50 feet away,” Hoekzema said.

In addition to the effect caused by nearby trees, the monitoring stations needed to be moved because they were not in areas of high population density, said Julia Cleary, Bastrop County planner and a representative for Bastrop County on the CAC Advisory Committee. This means the readings from the monitors would not accurately show the air quality of the area where most people live.

“Ozone is a public health issue,” Cleary said. “It was a two-pronged approach: one was to have it in areas that are closer to where the majority of people live and work, and the other one was the concern with the trees.”

While CAPCOG figured out the configuration of its monitoring network for 2019 through 2023, they decided to move one of the monitors in Travis County, move the one current Bastrop County monitor into a city and shut down a monitoring station in Fayetteville to move into another city in Bastrop County, according to the CAPCOG ozone monitoring network review report for 2019-2023. CAPCOG decided to shut down the station in Fayetteville in order to move it into the Austin-Round Rock MSA. The two cities in Bastrop County chosen for the monitors were Elgin and Bastrop.

Hoekzema said not every location is suitable for conducting ozone monitoring; the decision about a site needs to consider factors that might interfere with the quality of data. He added the main reasons the final sites in Bastrop and Elgin were selected were because of property ownership, access to electricity and distance from the road and trees.

“Once you go through the whole set of criteria, the number of suitable sites winds up being smaller than you might expect,” Hoekzema said.

The monitoring stations should be in place for the ozone monitoring season starting in 2019 and remain there through the monitoring season of 2023, Cleary said. Hoekzema said the EPA requires ozone monitoring in central Texas from March 1 through November 30, and the worst ozone problems usually occur in August and September.

During the November 13 city council meeting, the Bastrop City Council approved an agreement to move the McKinney Roughs Nature Park monitor to Mayfest Park in Bastrop.

“We want to ensure the readings in Bastrop are true and correct as much as we possibly can so we can still be in the attainment area, and not be burdened with some of the cumbersome EPA and TCEQ regulations that come about from being a nonattainment area,” said Mayor Pro-Tem Lyle Nelson, the representative for the City of Bastrop on the CAC.

Currently, CAPCOG is working with the City of Elgin and Elgin Independent School District to find a place for the monitoring station on Elgin ISD property. According to Elgin ISD deputy superintendent Peter Perez, a location has tentatively been chosen near the school district’s transportation department on Second Street. As of last week, the agreement has been signed by Elgin ISD and sent to CAPCOG, Perez said.

Mayor Pro-Tem Jessica Bega, the representative for the City of Elgin on the CAC, said Elgin is able to be involved at the regional level through CAPCOG and the CAC.

“As we (Elgin) are members, we also agreed to do our part with the overall effort to keep ozone levels at standard and not to exceed and move into a dangerous area,” Bega said. “The Clean Air Coalition is trying to set an example; in some cases, we have goals we try to meet on a yearly basis and try to bring the participating cities together to understand the base level and what we can do to keep air quality in check.”


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