Thousands of Americans have been warned to stay indoors as dangerous toxins pour into the air throughout the Southeast on Thursday.

The National Weather Service (NWS) has issued an air quality alert in Georgia and South Carolina as both ground-level ozone pollution and hazardous wildfire smoke have flooded into the region this week.

Wildfire smoke contains a complex mixture of toxic gases and fine particles, with carbon monoxide (CO) being the most common and immediate lethal threat near fires. 

Approximately four to five million Americans live in the areas under fire danger and air quality warnings through at least 8pm ET on Thursday, with some warnings lasting into the weekend.

The NWS alerts were triggered by a combination of high atmospheric pressure causing stagnant air, warm temperatures, low humidity and smoke drifting north from fires raging across southern Georgia and northern Florida.

Wildfire smoke has become the main driver of the pollution in the two states, sending out plumes of fine particulate matter, microscopic particles of toxic compounds, small enough to penetrate deep into the lungs.

The smallest of these particles, called PM2.5, produced by wildfire smoke, can exacerbate stagnant air, which 'traps' pollution near ground level with little to no wind moving it away from populated areas. 

NWS officials in South Carolina warned: 'Ozone will be in the Orange Zone today, meaning the air quality is forecast to be unhealthy for sensitive groups.'

A 'Code Orange' means the air will be unhealthy for anyone with lung disease, heart disease and breathing problems, as well as older adults and children. Breathing in these toxins can damage the lungs, worsen asthma and even contribute to heart attacks and strokes.

'Hazy conditions and a smoky smell can be expected across much of central Georgia and parts of north Georgia through Friday,' the agency added in a statement.

AccuWeather has said that the dangerous conditions in Georgia have been caused by severe drought, extremely low humidity and gusty winds, causing a perfect storm for wildfires to rage across thousands of acres.

AccuWeather Meteorologist Brandon Buckingham said: 'It’s unusual to see this level of wildfire activity across the Southeast in April. When soils and vegetation dry out this much, it only takes a single spark and a gust of wind to create a fast-moving wildfire.'

The US Environmental Protection Agency warned that the air over Columbia, South Carolina, home to more than 140,000 people, reached the 'unhealthy' zone for all residents Thursday morning.

Large swaths of Georgia, including over Augusta and Macon, have been deemed 'unhealthy for sensitive groups.'

NWS officials warned anyone in the path of the wildfire smoke to reduce or avoid outdoor activity, especially if they are engaging in strenuous work or exercise.

The greatest danger is expected to come in the afternoon and early evening when pollution levels are at their worst.

People with respiratory issues should move inside and keep their windows and doors closed. If using air conditioning, NWS urged people to keep the fresh-air intake closed and to make sure to clean the filter so smoke does not get inside.

In South Carolina, ozone alerts are expected to remain in effect until midnight in multiple cities, including Greenville, Spartanburg, Anderson, Greer, Mauldin, Simpsonville, Taylors, Easley and Clemson.

There are wildfire smoke warnings throughout the state, affecting Charleston, North Charleston, Mount Pleasant, Columbia, Aiken, North Augusta, and Lexington.

In Georgia, Atlanta and the surrounding metro area will be under an air quality alert for both smoke and ozone pollution throughout Thursday.

Two of the largest fires in the Peach State have been the Pineland Road Fire and one in Brantley County.

Statewide, the Georgia Forestry Commission reported that over 50,000 acres have burned so far in 2026. That is more than double the typical amount of wildfire destruction for this time of year.

In Florida, first responders have been dealing with major blazes across the state's panhandle region, including a massive wildfire in Collier County's Big Cypress National Preserve that has burned 35,000 acres.

AccuWeather has released a dire forecast for the rest of the year, predicting that between 5.5 and eight million acres of land across the US could burn.

Only 5.1 million acres burned down across America in 2025, well below the historical average of seven million over the last two decades.

'The fires can have far-reaching effects as winds carry smoke across the continent. When winds align with larger blazes, smoke can create a hazy sky and reduce air quality in areas hundreds or even thousands of miles away,' the AccuWeather team warned. 

Heavy wildfire smoke can also create larger particles of air pollution called PM10, which are tiny solid particles or liquid droplets floating in the air that are less than 10 micrometers in diameter, thinner than a human hair.

These inhalable particles can get deep into your lungs when you breathe them in and are typically created by dust from construction, pollen, mold, smoke, soot, industrial emissions, and wind-blown dirt.

Just like PM2.5, these larger particles of pollution carried by smoke can worsen respiratory issues such as asthma and contribute to heart attacks and strokes that cause premature death.