5 SLO County communities made the list for the world’s worst air on Friday
San Luis Obispo County continued to have some of the worst air quality in the world Friday, and for a time five local communities ranked in the top 10 for poorest conditions in the nation.
Gray haze has covered the entire county since Tuesday, but it’s especially thick and low in the North County where the smoke was so dense, visibility was reduced to a few blocks and some local restaurants closed outdoor dining.
Conditions Friday morning were only slightly better than Thursday, when four North County locations held the top four spots for the worst air quality in the United States, according to IQAir, an air quality monitoring company.
According to the San Luis Obispo County Air Pollution Control District, nearly the entire county has unhealthy air. The coastline, however, has moderate air quality, according to APCD.
As of noon Friday, Lake Nacimiento was ranked No. 3 for worst air quality in the nation, followed by San Miguel at No. 4, Paso Robles at No. 6 and Atascadero at No. 7. Earlier in the day, Los Osos also made the list, rising as high as No. 7.
IQ Air calculates its air quality index (AQI) by looking at the six most common pollutants — including particulate matter, carbon monoxide, sulfur dioxide, nitrogen dioxide and ground level ozone — and calculating the health risk for each. The overall AQI is determined by the most present and “riskiest” pollutant, according to IQAir.
The index rating is typically measured on a scale from 0 to 500, with anything over 300 being considered hazardous, and anything under 50 considered good air quality. The air quality from the fires burning around California has been so bad, some readings have even exceeded that scale.
Carmel Valley, for example, led the nation’s list at 628 at noon Friday.
Lake Nacimiento’s index rating was 429 as of noon Friday, according to IQ Air, followed by San Miguel at 372, Paso Robles at 340 and Atascadero at 319. Los Osos hit 312 before falling off the list and below hazardous conditions at midday.
One monitoring station in Shandon had an IQAir index of 430 Friday morning.
The poor air quality across the Central Coast is primarily a result of fires burning in Monterey County, creating tiny particulate matter known as PM 2.5.
According to the California Air Resources Board, an average of 35 micrograms per cubic meter is the maximum exposure to PM 2.5 people can have over a 24-hour period before they begin to experience health issues.
PM 2.5 exposure for even a 24-hour duration, has been associated with heart and lung issue, acute and chronic bronchitis, asthma attacks, emergency room visits, respiratory symptoms, and restricted activity day — especially for children, older adults and people with preexisting conditions, according to the air resource board. PM 2.5 is even small enough to travel through the respiratory system into the lungs and bloodstream.
In parts of North County, PM 2.5 levels have been exceeding healthy standards since Wednesday. According to APCD senior air quality specialist Karl Tupper, Thursday’s PM 2.5 levels broke county records set the day prior.
In Atascadero, air quality monitors recorded a 24-hour average of 242 micrograms per cubic meter. Wednesday’s record high was a 24-hour average of 135 micrograms per cubic meter.
As a result, the county Air Pollution Control District sent out a warning Friday urging people to stop all outdoor work in communities with an AQI over 150.
The APCD recommended people check www.slocleanair.org, or on www.airnow.gov for up-to-date information on the air in their area.
“On the map at AirNow.gov, areas with AQI above 150 will be colored red, purple, or brown,” the APCD said in its release. Currently, this includes all of North County. In these areas, we strongly recommend that restaurants close or switch to take-out only, and that outdoor agricultural and construction work stop. Outdoor recreation should also be postponed until conditions improve.”
When will the smoke clear?
PG&E meteorologist John Lindsey tweeted that the poor air quality will continue throughout the day Friday.
“Smoke cover can be hard to predict over a number of days, but over the next day or two, and likely beyond, we should prepare for poor air quality,” Lindsey told The Tribune on Thursday. “It is very unusual to have smoke spread across the region so broadly, as it is now.”
Lindsey said Thursday that winds from the northwest are bringing the smoke from Monterey County fires to San Luis Obispo County.
The fires continue to burn thousands of acres. The more than 6,000-acre Dolan Fire near Big Sur and the 4,000-acre Carmel Fire near Carmel were at 0% containment Friday morning, according to Cal Fire and the Los Padres National Forest Service.
The largest of the Monterey County fires, the River Fire near Salinas, was 9% contained and had reached more than 39,000 acres as of Friday morning, Cal Fire reported.
How to stay safe in smoky conditions
According to APCD, smelling smoke is a sign that you are in an area with poor air quality.
All adults and children should remain indoors if possible, avoid strenuous outdoor activity and close all windows and doors that lead to the outside to prevent bringing additional smoke inside.
If using an air conditioner, set the air conditioner to recirculate rather than bring in smoke.
According to the district, if smoke increases, healthy people could be affected as well.
This story was originally published August 21, 2020 at 12:48 PM with the headline "5 SLO County communities made the list for the world’s worst air on Friday."
