(NewsNation) — In Milford, Connecticut, Kassidy Philpott has had to take three days off of work since she started feeling sick on Monday.

“It feels like someone is sitting on my chest,” Philpott said. “I’ve been super congested. I feel like I can barely breathe.”

Heavy winds continue to push the smoke from more than 400 wildfires burning in Canada south into the U.S. Now, most of the country’s Northeast region is covered with a haze of very unhealthy air, affecting millions of people.

As an asthmatic, Philpott said the health effects of the smoke have been crazy. She has felt most of the known symptoms, including watery eyes, congestion and headaches.

“My throat feels like it’s on fire,” she said. “I feel like I’ve got every symptom that people are saying you could possibly get. And I feel like my skin’s been a little bit itchier than normal.”

She even thought initially she had COVID-19, but after taking multiple tests resulting in negative results, she realized it was from the unhealthy air quality.

“Our cars are covered in — I don’t even know what it is. It looks like pollen. But you know, it’s not pollen,” she said.

Her little sister, Elle Philpott, said she has also been feeling the impact of the smoke.

“I can barely see out of my windshield while driving because of the ash,” Elle said.

The 17-year-old, who also has asthma, said she and all the girls on her high school lacrosse team were having a hard time breathing during their games last week.

“I try to be outside as little as possible, but it still has affected my lungs and sinuses significantly. I have had headaches ever since the smoke started to affect Connecticut,” she said.

Not only has it constantly smelled like a campfire, but Elle also said the environment is “insanely eerie.”

But it doesn’t smell like a campfire just in Connecticut; Haley L., who lives in Philadelphia, said she smells it, too.

“We’ve really been noticing a very strong campfire smell every time we go outside, and we live right in the heart of Center City, Philadelphia. So that’s not usually a smell that we smell,” she said.

She said it is definitely disrupting her normal routine.

Haley L. usually takes her small puppy to the dog park every morning, but when they arrived Wednesday morning, the park was empty.

Within 10 minutes of the walk, the 26-year-old said she started getting a headache and her dog Louie was panting a lot more than normal. She checked the Air Quality Index, and it was at 184, well into a range considered “unhealthy.”

“I had a headache pretty immediately after going outside. I noticed that my nose was pretty stuffy,” she said. “And I think it definitely had to do with air quality, because as soon as I came inside, I washed my face and I changed my clothes, and then I felt a lot better.”

She said she hasn’t received any public health alert as she had a few months back when there were reports the water in Philadelphia was unsafe to drink, even though air quality alerts had been issued for at least 17 states.

Andrew in Arlington, Virginia, started to notice a difference on Monday. While on a run, he said he noticed he was having trouble breathing despite running at a relaxed pace.

“At the time, I just thought I had a bad run,” Andrew said.

It wasn’t until Tuesday that he realized something else was going on. He again started to have trouble on his afternoon walk. He looked up the air quality out of curiosity and saw that Arlington’s air quality score was in the 120s, which is unhealthy air quality for sensitive groups, according to the EPA’s Air Quality Index.

Andrew, who noticed a slight irritation in his throat after his walk, decided to stay indoors for the rest of the day and noticed the sky appeared dark as if it was about to rain — it didn’t.

On Wednesday, Andrew immediately noticed the haze. The air quality in Arlington was now above 180 on the EPA’s index. Normally, he would be able to see Washington from his apartment, which is just 2.5 miles away. But he couldn’t due to the haze.

During a press conference on Wednesday, New York Mayor Eric Adams and the city’s Health Department urged residents to stay indoors and close all doors and windows. Officials also suggested using air purifying if needed and limiting outdoor time. They said if someone must go outside, they should wear a high-quality mask like the ones worn during the pandemic.

The American Lung Association said if you can see and smell the smoke, consider yourself exposed.

Doctors warned that the consequences of increased exposure to this toxic smoke are very unhealthy.

“Ozone levels are high and the particulate matter is also high. And all of those things can damage the lungs and cause asthma attacks, respiratory issues, also heart attacks, other cardiovascular issues, increased risk of stroke. So air quality this bad actually has a lot of health consequences,” said Dr. Barbara Mann, a pulmonologist at Mount Sinai Hospital in New York.

Dr. Robert Lahita said it’s “very dangerous” to breathe in the air.

“You can have major irritation within your lungs and you can have difficulty breathing,” Lahita said on “Elizabeth Vargas Reports. “For those that have medical conditions like asthma, and chronic obstructive lung disease, the elderly, the very young … this could be a gamechanger and be very dangerous.”

Pregnant women are also at risk, according to Lahita.

“We don’t want them to cough, we don’t want them to sneeze or really have problems with their lungs while carrying a fetus. This is a really serious serious issue,” Lahita said.

All outdoor activities for public schoolchildren in New York City, almost a million of them, has been canceled until the air quality improves on Thursday. Schools in surrounding states have also postponed and limited outdoor activities.

Haley Walker from Lancaster, Pennsylvania, told NewsNation that parents were asked to pick up their children from day camps due to the unhealthy air quality.

“The camps were mainly outside (with) not a lot of space that they could be inside. So, a couple of people actually had to leave work to go and pick up their children and take them home so that they could be inside and not be in the air right now,” Walker said.

The air quality in Lancaster Wednesday hit 211 on the EPA’s Air Quality Index, Walker said, making it very unhealthy with increased risks of health effects for everyone.

“It’s just kind of like, more panicky, like, I know I’m inside, so I’m OK,” Walker said, “But the animals back home, there’s an AC unit. And so, do I take the AC unit out? Do I close the windows? Do I need to leave work to go and do that? And are they going to be OK?”

Dr. Zachary Glantz, the medical coordinator and associate veterinarian with Art City Vets in Philadelphia, said that while there are very limited studies on the effects of air quality on pets, they can extrapolate a lot from human medicine.

“Generally, birds are highly sensitive, as are asthmatic cats,” Glantz said. An estimated 10% of cats have asthma.

He suggested that when the air quality is poor, keep outdoor exposure limited, and windows and doors closed. In addition, to keep indoor air quality high, avoid frying food, smoking, vacuuming, and burning candles and incense.

“It’s just a lot of panic about what’s going to happen, or what I should be doing, or how I can make sure that everyone is staying safe,” Walker said.

Walker’s biggest concern: Is it going to get worse?

Health officials are uncertain how long the smoke will last, but said during the press conference that the situation could continue for several more days.