'Apocalyptic': Tahoe area's hazardous air is worst in North America


Lake Tahoe is situated in the worst possible place for wildfire smoke right now: immediately downwind from the Caldor Fire. 

According to air quality officials, the Reno Tahoe region and the central Sierra Nevada may even have the most toxic air in all of North America right now. 

Since Friday, a southwesterly wind has been directing the huge plume of smoke from the Caldor Fire directly into the Lake Tahoe basin, saturating the region with thick, toxic air that measures beyond hazardous on the Air Quality Index. 

On Monday morning, readings on AirNow showed a 620 AQI in Tahoe City. The Air Quality Index goes up to 500. Anything above 500 is labeled as “beyond index.”

“Anything beyond 500, there isn’t really a number that can be calculated,” said Brendan Schnieder, air quality specialist at the Washoe County Health District in Reno, Nevada. “It’s really 500-plus. It’s the worst it can get.”

When the Air Quality Index goes above 300, the air is considered “hazardous,” which AirNow describes as a “health warning of emergency conditions” that affects everyone. 

“Everyone should avoid outdoor activity,” Schnieder said. “And even if you’re inside your home, you should be doing light activity. It can cause a variety of health issues.”

According to the Environmental Protection Agency, wildfire smoke can trigger a wide range of health issues, from acute to very serious issues. Breathing toxic air from wildfire smoke can cause irritation in your lungs and eyes. It can reduce lung function, exacerbate asthma and heart failure. It can cause premature death. The EPA says that children, pregnant women and the elderly are especially vulnerable. 

Anecdotally, many people in Lake Tahoe and Reno say that this is the worst wildfire smoke they’ve ever experienced. Schnieder, who has lived in the Reno area since 2004, said he hasn’t been able to see the mountains in a long time. On Tahoe’s West Shore, in Tahoma, longtime resident Ed Miller compares it to the smoke he experienced during 2013’s Rim Fire in Yosemite. But he doesn’t remember the smoke lasting for as long or with the kind of intensity as it has this summer.

“It’s changed our lives,” Miller said. “Our everyday activities. For example, we used to take our puppy swimming almost every day in Homewood. And we’re not doing that anymore. We just canceled an appointment in Truckee, because we don’t want to go out. It’s very gloomy. It’s depressing. It’s anxiety producing.”

Lake Tahoe and parts of northern California and northern Nevada have some of the worst measurements on the Air Quality Index in North America right now. Schnieder said that virtually everywhere else in North America has a better AQI reading — that is to say, healthier and cleaner air — than the central Sierra Nevada, Lake Tahoe, Carson Valley and Reno area. 

Sunday even set a new record for air quality in Reno: The 24-hour average for Reno’s AQI was at 251, said Schnieder. On a typical summer day, without wildfires, Reno’s 24-hour average AQI hovers around 25 to 30. Sunday was the worst day on record for particulate matter 2.5, or PM 2.5, which is a measurement of the fine particles in the air from wildfire smoke. 

PM 2.5 is “the more concerning of the particulates because it can coat further down into your lungs,” Schnieder said. 

The record-breaking measurement in Reno comes from air monitors that are regulated by the EPA’s National Ambient Air Quality Standards, which Schnieder said is a separate source of records than AirNow and PurpleAir. The data for daily average on air quality goes back to the late 1990s, Schnieder said.

Schnieder also said that air quality in the Reno Tahoe region has developed a disturbing pattern that gets worse every year because of wildfires.

“Since 2013, we’ve had wildfire smoke impacts every summer,” Schnieder said. “2018 was notable. 2020 was even worse. And now 2021 is even worse than 2020. So it does appear to be this sort of pattern of more wildfire smoke-affected days. But also, those wildfire smoke-affected days are worse than they have ever been.”

Given how bad the air is in Reno, the Lake Tahoe Basin is located in closer proximity to the Caldor Fire, and many of the residents on the south and west shores are likely seeing even worse air quality. On Monday, AirNow maps showed hazardous air quality levels for many locations around the Tahoe Basin. SFGATE called El Dorado County air quality officials for comment about the smoke in South Lake Tahoe, but the health district was not available. (Mass evacuation orders due to the Caldor Fire have been issued near the El Dorado county seat in Placerville.)

For about 36 hours last week, Tahoe saw a brief reprieve from the wildfire smoke, which has been sitting in the basin for several weeks straight. On Thursday and Friday, a shift of winds graciously cleared the air; you could actually see the mountains on the other side of Lake Tahoe. There were blue skies. Tahoe residents and visitors were finally free to be outside, to go hiking, to swim in the water.

But the taste of summer was short-lived. Winds from the southwest picked up, blowing all the smoke from the Caldor Fire into Tahoe. 

“We’re right in the worst-case scenario spot,” said Scott McGuire, a meteorologist at the National Weather Service in Reno, which forecasts for northern Nevada and the Sierra Nevada. “We’re sandwiched between the Dixie Fire to the north that’s been burning for quite some time now, and then the Caldor Fire, southwest of Lake Tahoe.”

McGuire said that winds are going to stay consistent, blowing from that unfortunate southwestern direction, for the first part of this week. Later in the week, he said some signs are starting to show that winds may shift. But smoke forecasts depend on myriad factors, including the fire itself.

“At this point, the message is, we unfortunately are going to be dealing with some sort of smoke and haze issues for the foreseeable future,” McGuire said. 

In Tahoma, Miller is the president of the Meeks Bay Fire Protection District. He said he’s getting many calls from fellow community members, neighbors and friends, regarding the Caldor Fire and the smoke. He has two air filters in his house and he said his street has vacated because so many of his neighbors have left their homes. The visuals caused by the smoke are apocalyptic, he said.

“When you see the sun rise or the sun set,” Miller said. “We’re known for our spectacular sunsets, and when they turn to this hazy orange glow, it looks unearthly.”