Penn State leads project to improve air quality models for state decision makers

September 13, 2022

By Matthew Carroll

Editor’s note: This article originally appeared on Penn State News. Wei Peng, assistant professor of civil and environmental engineering and of international affairs, was mentioned.

UNIVERSITY PARK, Pa. — Improving states’ ability to address air quality issues is the focus of a new $1 million, Penn State-led project funded by NASA.

“We’re trying to improve the quality of information that states use to manage air pollution,” said Ken Davis, professor of atmospheric and climate science at Penn State and principal investigator on the project. “Those management decisions have real impacts and states want to have accurate plans and to get it right.”

The scientists aim to use state-of-the-art NASA land surface data to improve air quality simulations that states use when creating plans to deal with air pollution — referred to as state implementation plans.

States must develop these plans when they fail to meet National Ambient Air Quality Standards for pollutants like ozone or particulate matter.

“The states run numerical models that simulate weather conditions and atmospheric chemistry,” Davis said. “And in this modeling framework they can say, ‘if we reduce emissions by this much, then we will be compliant with air quality standards.’”

Because officials use these models to create plans for reducing air pollution, flaws in the models have tangible health, environmental and financial consequences.

“A flawed simulation of atmospheric winds and turbulence will lead to flawed air pollution estimates,” Davis said. “These flaws could cause a state to implement air pollution regulations that are either too strict or too lenient. Each type of error has negative consequences.”

The scientists believe they can improve the quality of information states have by tapping into a NASA system for assimilating land surface data collected by state-of-the art remote sensing techniques into the weather models.

“All these weather models describe interactions between Earth’s surface and the atmosphere,” Davis said. “Air pollution is down where we live. It’s close to the ground. And near the ground, there’s atmospheric turbulence that’s driven by interactions with the ground, the land. The mixing and the winds that result have a big impact on the air quality.”

Dry or moist conditions and even the roughness or smoothness of the landscape can all impact atmospheric mixing. NASA satellite-based instruments improve our knowledge of the surface conditions, and the data should also improve the simulations of atmospheric mixing, the scientists said.

The scientists will run the NASA modeling system with the land surface data side-by-side with existing state agency models. They will compare to see if the NASA system more accurately models drivers of atmospheric turbulence and the resulting atmospheric mixing and wind speeds.

“We will test both models with independent measurements,” Davis said. “My group are experts in deriving boundary layer depth from radar and lidar and measuring surface-atmosphere energy and momentum exchange. We’ll use these data to see if the NASA modeling system is getting the right answer for the right reason.

smog hovers over a range of pine tree-covered mountains

From Sequoia National Park, photochemical smog is visible over the San Joaquin Valley. Credit: National Park Service

The project will focus on two states: California and Pennsylvania. Both states have complex geographies — including irrigation in the San Joaquin Valley in California and a mix of urban, rural and wooded land in Pennsylvania — and incorporating the NASA land surface data should help improve the states’ models, the scientists said.

“If we can show this helps with both these places, we’ll have good evidence that many states should use this NASA remote sensing in their air quality simulations,” Davis said.

Other Penn State investigators on this project include Wei Peng, assistant professor of civil and environmental engineering and of international affairs; Scott Richardson, research professor in meteorology; Christopher Blaszczak-Boxe, associate research professor of geosciences; and Li Zhang, assistant research professor in meteorology.


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