South Lake Tahoe hitting record amounts of PM2.5 in the air leading to harmful air quality

SOUTH LAKE TAHOE, Calif. - Smoke from the Caldor Fire has been pouring into the Lake Tahoe Basin during the past week, but Sunday night saw record breaking numbers for bad air quality.

Smoke from wildfires contains chemicals, gases and fine particles that can harm health. The greatest hazard comes from breathing fine particles in the air, which can reduce lung function, worsen asthma and other existing heart and lung conditions, and cause coughing, wheezing and difficulty breathing.

At 9:00 p.m. in South Lake Tahoe on August 22, the Air Quality Index (AQI) was 600-800 PM2.5 in most areas, and some even saw into the 900s by the end of the evening. (The term fine particles, or particulate matter 2.5 (PM2.5), refers to tiny particles or droplets in the air that are two and one half microns or less in width. Like inches, meters and miles, a micron is a unit of measurement for distance. There are about 25,000 microns in an inch. The widths of the larger particles in the PM2.5 size range would be about thirty times smaller than that of a human hair. The smaller particles are so small that several thousand of them could fit on the period at the end of this sentence.)

According to AirNow, they don't even have recommendations for PM2.5 levels above 500, but they offer guidance (HERE) and suggest clean sleeping rooms and to not go outside.

"The Caldor Fire is creating hazardous air conditions in and around the Lake Tahoe Basin," said Barton Health Spokesperson Thea Hardy. "At an AQI of 300 and above, airborne pollutants can cause harm to all groups; exposure to smoke can cause coughing, watery and itchy eyes, difficulty breathing, and other problems. At this time, it is recommended to avoid outdoor activities, particularly outdoor exertion. Children, elderly and people with illnesses, particularly respiratory problems, should remain indoors. Keep windows and doors closed, run your bathroom exhaust fans, and use an air purifier when possible. It is also recommended you limit the outdoor physical activity of your pets in smoky conditions. Anyone experiencing questionable or severe symptoms from smoke exposure should seek professional medical advice and/ or treatment. In case of emergency, dial 9-1-1."

El Dorado County Air Quality Management District (AQMD) said wearing an N95 mask is one of the best defenses against the bad particles in the air as the particles are not deterred by cloth masks. Also, using HEPA filters in air systems but since many Lake Tahoe homes do not have air conditioning, that will not help. Staying inside with windows closed will keep out most harmful particles.

For people that want to check out the AQI in their area, they recommend looking at a 24-hour period since the quality can change every few minutes. As an example, in the photo above, use one of the two preferred methods of testing - www.airnow.gov or www.purpleair.com. On Purple Air, open it up to your area and select EPA PM2.5 AQI, drop down US EPA and select "one day average graphic). This will give you the average for the day and the PM2.5 numbers in your area.

"Expect more of the same for the foreseeable future," said Scott McGuire, forecaster for NWS-Reno. He said they use the data from www.airnow.gov.

There is no air quality policy in Nevada that covers employees through Occupational Safety and Health Administration (OSHA), but Cal/Osha, the California Department of Industrial Relations, says employers must take precautions when the AQI reaches PM2.5 151 up to 300, and above 300 they must perform air tests during the work day

"The smallest and usually the most harmful particulate matter is called PM2.5 (solid particles and liquid droplets suspended in air with an aerodynamic diameter of 2.5 micrometers or smaller)," Cal/OSHA outlines in their guidance.

They inform employers that they must provide a sufficient number of respirators for employee use on a voluntary basis when the current AQI for PM2.5 is equal to or greater than 151 but does not exceed 500. The employer must require employees to use respirators when the current AQI for PM2.5 is greater than 500.

Schools

Washoe County School District closed the Incline Village schools Monday due to poor air quality, but the first day of school for Douglas County had all locations open. Douglas County School District (DCSD) follows poor air quality protocol, but that doesn't specify when schools have to close, it defines what students can do within certain AQI ranges. When the AQI is PM2.5 of 301-500, all kids are kept indoors. Caryn Harper, DCSD secretary to the superintendent and board, said all schools in the district have ventilation systems to protect those inside, including the lake schools.

In South Lake Tahoe, the Lake Tahoe Unified School District is currently discussing what criteria they will be using after meeting with department heads and school sites. They will be sending out a letter this week ahead of the first day of school August 30.