The dangerous air in the Tahoe area is the worst in North America

Since Friday, a southwest wind has directed the enormous plume of smoke from the Caldor fire directly into the Lake Tahoe basin, saturating the region with thick, toxic air that is measured beyond dangerous on the air quality index.

As of Monday morning, readings on AirNow showed an AQI of 620 in Tahoe City. The air quality index goes up to 500. Anything above 500 is labeled “above the index”.

“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 over 500. It’s the worst that can be.

When the air quality index exceeds 300, the air is considered “hazardous”, which AirNow describes as a “health warning of emergency conditions” that affects everyone.

“Everyone should avoid outdoor activities,” said Schnieder. “And even if you’re inside your home, you should be doing some light activity. It can cause various health problems. “

According to the Environmental Protection Agency, smoke from wildfires can trigger a wide range of health problems, from acute problems to very serious. Breathing toxic air from smoke from a forest fire can cause lung and eye irritation. It can reduce lung function, worsen asthma and heart failure. It can cause premature death. The EPA says children, pregnant women and the elderly are particularly vulnerable.

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

“It changed our lives,” Miller said. “Our daily activities. For example, we took our puppy for a swim almost every day at Homewood. And we don’t do it anymore. We just canceled an appointment at Truckee because we don’t want to go out. It is very dark. It’s depressing. It produces anxiety.

Lake Tahoe and parts of northern California and northern Nevada currently have some of the worst air quality index measurements in North America. Schnieder said that virtually everywhere else in North America the AQI reading is better – that is, healthier, cleaner air – than the central Sierra Nevada, Lake Tahoe, Carson Valley and Reno.

Sunday even set a new record for air quality in Reno: The 24-hour average for Reno’s AQI was 251, Schnieder said. On a typical summer day with no forest fires, 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 measure of fine particles in the air from forest fires. smoke.

PM 2.5 is “the particles of most concern because it can settle deeper in your lungs,” Schnieder said.

The record-breaking measurement at Reno comes from air monitors regulated by the EPA’s National Ambient Air Quality Standards, which Schnieder says is a separate source of records from AirNow and PurpleAir. Data on daily average air quality dates back to the late 1990s, Schnieder said.

Schnieder also said the air quality in the Reno Tahoe area has developed a disturbing pattern that is getting worse every year due to wildfires.

“Since 2013, we’ve had wildfire smoke impacts every summer,” Schnieder said. “2018 has been remarkable. 2020 was even worse. And now 2021 is even worse than 2020. So it looks like this kind of pattern of days more affected by smoke from forest fires. But also, those days affected by smoke from wildfires are worse than they have ever been. “

Considering the air quality in Reno, the Lake Tahoe Basin is located near the Caldor Fire, and many residents of the South and West Rim are likely seeing even worse air quality. On Monday, AirNow maps showed unsafe air quality levels for many places around the Tahoe Basin. SFGATE called El Dorado County air quality officials for comment on 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 El Dorado County headquarters in Placerville.)

For about 36 hours last week, Tahoe enjoyed a brief respite from the smoke of a wildfire, which has been lingering in the basin for several weeks in a row. Thursday and Friday, a change of wind gracefully cleared the air; you could actually see the mountains across Lake Tahoe. There was a blue sky. Residents and visitors to Tahoe were finally free to be outdoors, to hike, to swim in the water.

But the taste of summer was short-lived. Southwesterly winds picked up, blowing all the smoke from the Caldor fire into Tahoe.

“We’re in the worst case,” said Scott McGuire, a meteorologist with the National Weather Service in Reno, who forecasts northern Nevada and the Sierra Nevada. “We’re sandwiched between the Dixie Fire in the north which has been burning for some time now, and then the Caldor Fire, southwest of Lake Tahoe.”

McGuire said the winds will remain constant, blowing from that unfortunate southwest direction, for the first part of this week. Later in the week, he said some signs were starting to show the winds could change. But the smoke forecast depends on a myriad of factors, including the fire itself.

“At this point, the message is that we’re unfortunately going to be facing some sort of smoke and haze issue for the foreseeable future,” McGuire said.

In Tahoma, Miller is the chairman of the Meeks Bay Fire Protection District. He said he received many calls from community members, neighbors and friends, regarding the Caldor fire and smoke. He has two air filters in his house and he said his street had opened up because many of his neighbors had left their homes. The visuals caused by the smoke are apocalyptic, he said.

“When you see the sun rise or set,” Miller said. “We’re known for our spectacular sunsets, and when they look up to that hazy orange glow, it feels supernatural.”