Heather Heinks with the San Joaquin Valley Air Pollution Control District says, "We've got a high-pressure ridge that's been sitting over us for a while, which unfortunately means the smoke doesn't disperse."
The San Joaquin Valley Air Pollution Control District says four different fires are impacting air quality in the Valley.
The 85,000 acre SCU Lightning Complex Fire is burning in five counties just northwest of Merced, including Stanislaus. At noon on Wednesday, the particulate matter spiked to a Level 5 in Merced, meaning it was very unhealthy for everyone.
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Heinks says, "Particulate matter is what you find in smoke, and it's microscopic and something that's important to note is the masks we wear to prevent the spread of COVID do not protect you from inhaling particulate matter. It is microscopic and it can pass right through the paper and cloth masks we use."
Health experts say the symptoms of prolonged exposure can range from headaches and scratchy throats to difficulty breathing and cardiovascular issues.
Lung specialist Dr. Sunit Patel is concerned his patients could end up hospitalized if they spend time outdoors.
Pulmonologist Sunit Patel says, "As it is with COVID the hospitals are full, and if they have to go to the ER, their wait will increase, hospital admission rates are going to increase, and beds are scarce right now because of COVID, so that is my biggest worry."
Patel recommends people of all ages stay inside as much as possible, which is a little easier with students going back to school virtually.
"This would actually be the time that we would be concerned ozone and idling cars at school sites, so if there's a teeny tiny silver lining, maybe it's that's there are not people lined up at schools all across the Valley this week and everyone is inside hopefully staying safe," says Heinks.
The air district says the potential for windy conditions at times this week could help disperse the smoke a bit, but may also kick up dust.
You can monitor the air quality conditions in your area on the Valley Air District's website or app.