CASE STUDY

Defending Community Air Quality: Helping Clark County Prove Wildfires Drive Air Quality Exceedances

Across the Western United States, wildfire smoke has become one of the most significant and least controllable drivers of air quality challenges. In Clark County, Nevada, home to more than two million residents, even distant wildfires can send ozone-forming VOCs and fine particulates drifting into the Las Vegas Valley, triggering spikes that threaten ozone attainment status and reinforce misconceptions about local pollution. Yet for years, they lacked a defensible, data-driven way to show when these exceedances were caused by transported wildfire smoke rather than local emissions.

The Challenge: How to Prove What Isn’t Your Fault

For years, Clark County’s Department of Environment and Sustainability has operated under pressure to meet federal air quality standards.

Southern Nevada’s air quality metrics, particularly ozone, have drawn heightened attention from the Environmental Protection Agency (EPA) and national health organizations.

The irony? Much of what’s driving the problem isn’t even local.

“People look out over the valley, see haze, and assume our air is unsafe,” said Kevin MacDonald, Public Information Administrator for Clark County. “But a significant portion of what we’re dealing with originates elsewhere, in this case wildfires hundreds of miles away.”

Those wildfire emissions, rich with volatile organic compounds (VOCs) that serve as ozone precursors, can drift into the Las Vegas Valley long after flames are out. But until recently, proving that in an approach regulators would accept was nearly impossible.

The Turning Point: A Partnership for a Persistent Problem

Facing growing regulatory pressure and costly EPA fines, the county needed a defensible, data-backed way to distinguish wildfire-driven air impacts from local emissions.

That’s when they turned to Enthalpy Analytical, experts in air quality lab analysis and advanced VOC testing, and Spheros Environmental (formerly Sonoma Technology), research partners known for their work on exceptional event demonstrations.

Together, the team launched a multi-year air quality study across the Las Vegas Valley to answer one critical question.

When ozone and particulate levels spike, is it Clark County’s fault, or distant wildfire smoke?

Dr. Crystal McClure, Senior Atmospheric Data Scientist at Spheros Environmental, wanted to pair an active air sampling approach using TO-17 thermal desorption tube analysis with standard TO-15 canister tests to capture wildfire-specific VOCs.

“I’d worked with Enthalpy before, and knew the expertise they brought to the table,” said McClure. “They knew the compounds I wanted to test and had the expertise and capability to develop a real solution to test this TO-17 active sampling approach.”

Yousaf Hameed, Principal Air Quality Specialist with Clark County, echoed that sentiment:

“TO-15 is one thing, but there aren’t many labs who have the expertise and capability to handle TO-17 analysis and the complex logistics this project requires. The Enthalpy team was willing to roll-up their sleeves to create customized solutions alongside us and Spheros Environmental to help make this project a success.”

The Approach: Turning Complex Chemistry into Clear Evidence

The first season, in 2023, offered a calm start. Few wildfires meant little immediate data, but it became the perfect opportunity to fine-tune logistics and create a strong baseline of air quality in the area.

“The first year was slow, which turned out to be a really good thing,” said Hameed. “There are a lot of moving pieces to this project. By year two we had the process operationalized to handle a greater data workload.”

By 2024, wildfire smoke was back.

Through rigorous QA and QC, repeatable methods, and deep technical collaboration between Deer Park and Durham labs, Enthalpy turned every sample into a defensible story: when ozone levels rose, so did wildfire-specific tracers like acetonitrile and 2-butanone.

Using advanced Positive Matrix Factorization (PMF) modeling, the team built distinct “chemical fingerprints” separating local emissions (like vehicles) from wildfire plumes.

“We could finally say with confidence, which day and spike, was wildfire smoke,”

— Dr. Crystal McClure, Senior Atmospheric Data Scientist, Spheros Environmental

The Results: From Data to Regulatory Relief

Three years in, Clark County now has hard evidence that wildfires play a measurable role in air quality exceedances. The data is being folded into the county’s State Implementation Plan and Exceptional Event Demonstrations — critical documents regulators use to determine attainment status.

“Science is supposed to be repeatable,” said Hameed. “Thanks to Enthalpy and Spheros Environmental, we have a framework that’s working, and a dataset we feel confident in, not just for regulators, but to share with the broader scientific community to push everyone forward.”

It’s more than a technical win with better data, it’s a shift in narrative.

“This gives us a better story to tell,” said MacDonald. “We can show residents, regulators, even the media, that our air quality challenges often come from beyond our borders. Air quality here is better than people think, and we’re constantly taking steps to get better.”

What’s Next

The project will continue through at least 2028, capturing additional wildfire seasons to strengthen the dataset. Each new year adds more statistical power and more credibility.

“Our goal is to build an undeniable body of evidence. More data, better resolution, stronger science,” said Hameed.

For Enthalpy, that means continuing to provide advanced analysis that turns chemistry into confidence and helping agencies across the country separate what they can control from what they can’t.

Want to turn air quality into a defensible data-backed story? Talk to an expert today.