When Tammy Daniels left her Matthews home Wednesday morning, she “couldn’t even see across the yard.” Thick smoke covered the area, swept in by the wind from untamed wildfires 90 miles to the west in the North Carolina mountains.

Daniels, co-owner of We Hang Christmas Lights, worked outside all day in uptown Charlotte, breathing in the smoky air as she oversaw a crew decorating trees outside the NASCAR Hall of Fame. By the end of the day, she said, “I’m going to have a headache.”

As smoke from the high country poured east, the Charlotte region was placed under a Code Red air quality warning, meaning the air is unhealthy for all groups, but particularly older adults, active people and those with heart and lung problems.

Most people didn’t need the warning to know it was bad. They could see it and smell it.

“You would think one of your neighbors was having a camp fire,” Daniels said. “You could instantly feel it.”

As people walked through uptown’s Latta Arcade on their way to work and lunch, shoeshine man Tony Carey said everyone was talking about the haze that hung like fog over the city, burned eyes and set noses running. Some people wore masks for protection.

The smoke isn’t going anywhere soon. The fires continue to burn. So far, 44,000 acres have been consumed.

Forecasters with the state Division of Air Quality expect the Charlotte area to improve Thursday to Code Orange – air quality that’s dangerous for sensitive groups such as people with respiratory conditions. Code Red remains for the southern foothills, including the Hickory area northwest of Charlotte.

A high pressure system will blow smoke from fires near Morganton and Lake Lure to the south, the division said. On Saturday, a strong cold front is expected to sweep away most of the smoke from the state.

Charlotte’s haze dissipated some by midday Wednesday, but Charlotte-Mecklenburg Schools issued an advisory about 11 a.m. to keep students indoors “as much as possible today.”

The district also cut all football practices to 45 minutes and canceled the Polar Bear Invite scheduled at Olympic High School Wednesday afternoon.

Private schools made similar accommodations. At Charlotte Country Day, for example, physical education classes for fifth- to eighth-grade students were changed to eliminate “running of the mile or warm up laps,” and recess was moved indoors when possible.

Symptoms of exposure to smoke particles include irritation of the eyes, nose and throat, coughing and shortness of breath. The effects increase with exercise or extended activity outdoors. Health officials especially advise people with significant health problems to stay indoors and reduce their exposure to bad air.

Carmen Walser, a respiratory therapist with Novant Health’s cardiopulmonary rehabilitation program, called three of her “very fragile” patients Wednesday and told them to stay home from their regular exercise programs. The patients all use supplemental oxygen to aid breathing because of heart problems or lung disease, such as asthma or chronic obstructive pulmonary disease (COPD).

“You want them to embrace the exercise,” Walser said, “but today the benefits would be outweighed by breathing in the smoke.”

Walser, who has mild asthma herself, said she didn’t pay enough attention to news advisories about bad air and took her dog for a brisk walk Wednesday morning. When she returned home, she said, “I had to use my inhaler. I hadn’t used it in a couple of months.”

Smoke inhalation can be life-threatening for people who already have heart and lung problems, said Dr. Michael Zgoda, with University Pulmonary Associates and president of the medical staff at Carolinas HealthCare System-University. “People that are most vulnerable are the very young and the very old.”

Carolinas HealthCare emergency departments are seeing an increase in patients with respiratory problems, Zgoda said. And his pulmonary clinic has seen a 50 percent increase in visits from patients having trouble breathing because of the smoke.

“We see the sickest of the sick,” Zgoda said. “Those are the first people coming in. We think of them as the proverbial canary in the mine. … Now we’re going to start seeing our regular asthmatics coming in the next couple days.”

Unlike second-hand smoke from cigarettes, Zgoda said, particulate matter from wildfire smoke “can be swept out by the lungs,” so it’s “highly unlikely there will be long-lasting effects” in people who are generally healthy. Wearing a mask can minimize exposure, but staying indoors is the best protection.

“If you’re outside and smelling smoke, you’re breathing that in,” he said. “It’s better that you get out of the smoke.”

Staff writers Michael Gordon and Bruce Henderson contributed.