Dangerous soot levels continued Wednesday morning in Fresno, Tulare, Kings and Kern counties, but a storm forecast Thursday could make breathing a little easier.
For the last eight days, the Valley has been under siege from high levels of soot and other debris that can trigger asthma and heart problems.
The San Joaquin Valley Air Pollution Control District earlier this week advised residents to check hourly updates online and stay inside as much as possible.
"This is related to the dry winter we're having," said air district executive director Seyed Sadredin. "We've had no cleansing wind or storms. This is affecting the whole Valley."
However, a northwest wind of 10 to 20 mph is expected Thursday. There is a slight chance of rain in the Fresno area. But the storm probably won't clear out enough pollution to make a big difference, the National Weather Service reported.
Microscopic pollution specks dominated the atmosphere on Monday, Tuesday and Wednesday in the Valley. The Valley had the nation's worst particle pollution, known as PM-2.5, according to the U.S. Environmental Protection Agency's website.
At 8 a.m. Wednesday, Visalia's air monitor showed 130 parts of soot per cubic meter of air -- the threshold is 35 parts per cubic meter averaged over a full day. Fresno, Hanford and Bakersfield had readings higher than 100 parts per cubic meter.
Such soot levels are considered very unhealthy, even for adults with no lung problems. Children, senior citizens and those with sensitive lungs are more vulnerable to the pollution.
The tiny specks of pollution come from fireplaces, diesel engines, cars and other sources. The pollution has been building in the stagnant Valley air for more than a week.
Doctors in Fresno reported seeing patients with complaints of coughing, wheezing and shortness of breath because of the bad air.
Over the last several days, air district leaders have been prohibiting wood burning in fireplaces for many parts of the Valley. Holt said this is among the more intense PM-2.5 episodes in the last few years.
People who violate the no-burn orders could be cited and fined. More than 125 notices of violation have been written Valleywide this year through Tuesday, compared to 78 at this point last year. The fine for violating the no-burn order is $50.
• Check hourly air readings
• Check wood-burning restrictions
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