Antony Chen

Ensuring environmental health with better air quality

Lake Tahoe’s water clarity has historically served as a marker for the environmental health of the entire basin. But Lung-Wen “Antony” Chen, associate research professor at the Desert Research Institute’s Atmospheric Sciences Division, says the air also interacts with the lake and land in ways that have long-lasting impact on the basin’s health.

For Chen, gaining a better understanding of this dynamic begins with examining long-term trends in air quality while also getting down to the particle level. He has been analyzing air quality data dating back to the 1980s, which includes trends in airborne particle concentration, chemical composition, and distribution as well as atmospheric visibility conditions.

“Particulate matter in the atmosphere has an effect on the climate, human health and visibility,” Chen said. “The Lake Tahoe area is such a pristine environment, even a small contamination can have a
big impact.”

Though air quality has slowly improved over time, particle concentration in recent years has spiked on the haziest days. These increases coincided with wildfire activities, including the Angora fire of 2007.

“These big spikes can actually cause the trend to go upward,” Chen said. Climate change can also contribute to worsening air quality, he said, since warmer temperatures result in more fires.

Close attention should also be paid to prescribed burns to minimize adverse effects on air quality, Chen said. Prescribed burns dispose of bushes and grasses that can serve as fuel for potential wildfires. The burns are usually small and planned for days that minimize impacts, but they could have small, cumulative effects, on the air and also on the lake water through deposition.

Recent studies estimate that 15 percent or more of the pollutants that lead to diminishing water clarity, such as particles and nutrients, fall into the lake directly from the air. Still, Chen said, much uncertainty surrounds those estimates. Previous deposition studies focused on ambient concentrations. In order to arrive at a better estimate, Chen is measuring the particle deposition directly around the lake everyday, as well as examining the particles themselves.

“If you really want to assess the source of particles and their impact on lake clarity, you need to have information on the particle’s size and chemical composition,” he said.

Though water and air quality have been improving over the past 30 years, Chen said detailed studies could help prevent air and water quality from worsening. Chen and his colleagues work closely with local groups like the Tahoe Regional Planning Agency and the U.S. Forest Service to advise them on how prescribed burning and other
activities might impact the air quality and the lake.

“The long-term goal is to mitigate the human influence and return the basin to its natural condition as much as we can,” he said. “We want to maintain the lake for the next generation. We have a responsibility to do that.”

This desire to do work that has a larger impact is evidenced by Chen’s body of research, even before he joined DRI in 2002. When Chen was a graduate student at the University of Maryland, he was given the choice to study pollution issues or create semiconductors for smartphones.

Chen knew the answer was obvious.

“I like my research to have an impact on the well-being of mankind,” he said. “The challenge we face in our generation is climate change. I hope that I can make some contributions that help solve the problem.”