FRESNO, Calif. (KFSN) -- What you're seeing on Fresno County roads isn't a foggy day.
What you see is smoke plaguing the San Joaquin Valley region for a second day.
Valley Air District Communications Manager, Heather Heinks says, "What's in smoke, that's microscopic pieces of matter. That's dust, soot and it's so small, you breathe it into your lungs and it goes into your bloodstream through your lungs."
As fire crews work to combat the KNP Complex and Windy fires, the ominous views can be seen from across the Central Valley.
Fresno County spent most of Wednesday hovering around levels 3 to 5 air quality.
Heinks says, "Level 4, you should be modifying activities and Level 5, everyone should come indoors."
We've all become used to seeing the color-coded air quality forecasts -- but those are predictions made the day before -- and they average out an entire day.
During fire season, the experts say you really need to be looking at real-time air quality data the same way you check the radar during a rainstorm.
The Valley Air District has an app for that, and the EPA's Air Now website is a great resource.
Heinks says their app provides real-time data on ground-level air quality, as opposed to their forecast that averages the anticipated AQI levels the day before.
Breathing in the fine particles in wildfire smoke can reduce lung function and worsen asthma and other existing heart and lung conditions.
RELATED: KNP Complex Fire: More evacuation warnings issued in Tulare County; smoke affecting Valley air
"It offers temporary monitors put into the system that isn't reporting back to those major networks that are on the ground in the communities nearest the fire," she said.
Kaiser Pulmonary Critical care specialist Dr. Mickey Sachdeva says it's important to look at AQI in real-time before stepping outdoors.
He adds, "There are also recent studies that suggest it can be as harmful as car pollution that we experience in big cities like LA. So very, very detrimental to our lungs and breathing."
In addition to the elderly population and younger children being most severely impacted, those with respiratory conditions can see their symptoms amplified.
Dr. Sachdeva says, "People with asthma, COPD, we see increased hospitalizations, increase in their flare-ups. People get sicker with these conditions."
Experts say limit your time outdoors and if you must be outside, have a fitted N95 mask to protect your lungs from particulate matter.