zooming in on emissions

UH team unlocks innovative approach to pinpoint pollution factors

A University of Houston team looked into what areas in Houston had the highest impact on emissions and how certain meteorological factors play into ozone formation. Photo via UH.edu

A team of researchers at the University of Houston are using machine learning to help guide pollution fighting strategies.

As reported in the journal Environmental Pollution last month, the team used the SHAP algorithm of machine learning (a game theory approach) and the Positive Matrix Factorization to pinpoint what areas in Houston had the highest impact on emissions and how certain meteorological factors play into ozone formation.

The paper was authored by Delaney Nelson, a doctoral student at the Department of Earth and Atmospheric Sciences of UH, and Yunsoo Choi, corresponding author and professor of atmospheric chemistry, AI deep learning, air quality modeling and satellite remote sensing.

The team's research closely tracked nitrogen-based compound and volatile organic compound measurements from Texas Commission on Environmental Quality's monitoring stations in the Houston area. After importing measurements from The Lynchburg Ferry station in Houston's ship channel and the urban Milby Park station, the machine learning and SHAP analysis showed a chemically definitive difference between the two areas.

For example, at the industrial station, the most impactful sources of pollution were from oil and gas flaring/production. At the urban site n_decane and industrial emissions/evaporation had the most impact on ozone.

According to Nelson and Choi, this shows that the machine learning and SHAP analysis approach can be used to tailor more precise air quality management strategies in different areas based on the site's unique characteristics.

“Once we know the specific emission sources and factors, we can develop targeted strategies to reduce emissions, which will in turn reduce ozone in the air and make it healthier for everyone," Choi said in a statement.

“Pollution is a critical issue in Houston, where you have extreme high heat and high concentration of ozone in the summers. The types of insights we got are very useful information for the local community to develop effective policies. That’s why we put our time, effort and technological expertise into this project," he continued.

Next the team envisions applying their approach in different cities and across the country.

“Austin, San Antonio and Dallas all have different characteristics, so I expect (volatile organic compound) sources will also be different,” Choi said. “Identifying VOC sources in different cities is very important because each city should have its own unique pollution fighting strategy.”

This summer, the City of Houston released an updated report on its major strategies to combat climate change and build a more resilient future for its residents.

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A View From HETI

After recently divesting from wind and solar energy initiatives, Shell has plans to quadruple EV charging stations in the next several years. Photo via shell.com

As it downshifts sales of fuel for traditional vehicles, energy giant Shell is stepping up its commitment to public charging stations for electric vehicles.

In a new report on energy transition, Shells lays out an aggressive plan for growing its public network of charging stations for electric vehicles (EVs). The company plans to boost the global number of public EV charging stations from about 54,000 today to around 70,000 by 2025 and about 200,000 by 2030.

The projected growth from today to 2030 would represent a 270 percent increase in the number of Shell-operated EV charging stations.

“We have a major competitive advantage in terms of locations, as our global network of service stations is one of the largest in the world,” Shell says in the report.

Shell’s global network of service stations is shrinking, though. In the report, the company reveals plans to close a total of 1,000 gas stations in 2024 and 2025. Today, more than 45,000 Shell-branded gas stations are located in over 90 countries.

Aside from Shell gas stations, the company’s Shell Recharge business unit operates public EV charging stations along streets, at grocery stores, and at other locations in 33 countries.

Shell, whose U.S. headquarters is in Houston, is ramping up its EV charging network amid forecasts of slowing demand for oil and rising demand for EVs. Other than EV charging, Shell is focusing on biofuels and integrated power as components of its revamped product mix.

“Shell is well positioned to become a profitable leader in public charging for electric vehicles, meeting the growing demand from drivers who need to charge on the go,” the report says.

To accelerate its EV charging presence in the U.S., Shell in 2023 purchased Volta, a San Francisco-based operator of EV charging stations. Shell says it now operates one of the largest public EV charging networks in the U.S., with more than 3,000 charging points in 31 states and another 3,400 under development.

“The availability of charging points will be critical for the growth in electric vehicles,” the report says.

Last month, Shell divested from a solar energy subsidiary, before later announcing an exit from a wind energy joint venture.

"In-line with our Powering Progress strategy, Shell continues to hone our portfolio of renewable generation projects in key markets where we have an advantaged position," Glenn Wright, senior vice president at Shell Energy Americas, said in a news release at the time.

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