A thick fog is sweeping across the US with locals in multiple states reporting how a 'burning chemical-like smell' has blanketed their communities.
Concerned Americans have flooded social media with videos of what looks like white particles raining down and swirling in the air.
Some witnesses have also claimed the fog has also triggered health symptoms similar to a respiratory illness.
A Florida resident told DailyMail.com that they stopped at a gas station for about 10 minutes and began feeling ill.
'Within about and hour, I kept sneezing over and over for about three hours, and my eyes were really puffy,' she said.
'I got very warm and I felt like I had a fever, and my stomach was cramping.'
Parts of Texas, Wisconsin, Iowa, Maryland, Virginia, West Virginia, Nebraska, Kansas, Oklahoma, North Dakota, Florida, and Minnesota were under fog alerts when the bizarre reports surfaced this week.
Similar experiences have also emerged from parts of Canada and the UK, sparking widespread concern.
Conspiracy theories are running rampant with people suggesting the fog could be a kind of chemical weapon or is related to the drones that mysteriously plagued the nation in December.
'Well weren't there drones that sprayed something? I seem to recall some videos of that somewhere... No idea of the validity though,' asked one X user.
A Texas woman shared on X that her dog has been 'acting strange' when it goes outside.
'[She] keeps smelling the air,' Sandra Jenkins Webb posted, adding that she was experiencing burning eyes, a mild cough, stomach aches and headaches.
Another woman in Kansas shared that there were 'massive amounts of chemtrails' over the area in a week, followed by a dense fog.
And a California resident shared on X Monday: 'Here in SoCal, unusual fog the last few days. Strange smells, but I've been noticing the smell for months now, burns my nose. Seems like an all-out assault from the skies the last few days.'
David Bamber, from St Petersburg, Florida, shared a TikTok video of himself walking through the dense fog.
He explained that fog typically dissipates later in the day, but the the current natural phenomenon lingers into all hours of the night.
'The weirdest part is the taste and smell,' said Bamber. 'It's smells like after you set off a bunch of fireworks and the taste of the air is toxic. It is super weird.'
However, the National Weather Service (NWS) issued a dense fog advisory for multiple states, suggesting there could be a scientific explanation behind the bizarre reports.
While the particles may seem unusual, fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface.
Shining a light in the fog makes these particles visible.
As for the 'chemical' smell people have described, the fog can absorb and trap polluted air near the Earth's surface, acting as a carrier for car exhaust, industrial emissions and other airborne chemicals.
Did anybody have poisonous fog on their 2025 bingo cards? 🤔
Apparently, there are some reports of people saying this fog smell smells like burning plastic!
pic.twitter.com/EakjxVbVdf
— Sarah Smith (@Defundmedianow) January 2, 2025
'When fog forms, sulfur oxides, nitrogen oxides, and other polluting gases are taken up or 'scavenged' by fog water droplets,' explained Rudolf Husar, a Washington University atmospheric scientist, in an article for NASA Earth Observatory.
What's more, smells become more potent in humid air because the water droplets trap the odor-causing molecules and allow them to linger for longer and remain concentrated.
This is not unusual for this time of year.
Fog forms when the temperature cools to the dew point, or the temperature at which air can become completely saturated with water.
Much of the fog currently hanging over the US is likely advection fog, which typically forms in winter when warm, moist air flows over colder land.
This is commonly seen over the southern or central US, where many affected states are located.
Some states, such as Minnesota, are also experiencing radiation fog that occurs in air with a high dew point.
It forms when the sky is clear, temperatures reach the dew point and winds are low enough to cause minimal atmospheric mixing.
While fog typically looks like a soupy gray mist, shining a light directly through it causes the light to scatter off of each individual water droplet that makes up the fog, reflecting that light back towards your eyes.
This makes each droplet appear as a small 'particle' within the beam of light, as is shown in many of the photos and videos recently shared online.
The 'chemical' smell associated with this recent fog is likely not coming from the fog itself, but rather from pollutants that were already present in the air when the fog formed.
The respiratory-illness-like symptoms people have been reporting can also be explained by natural fog.
Multiple studies have shown that fog can cause respiratory issues such as coughing, shortness of breath, chest pain, congestion and wheezing, especially in people with asthma.
That's because our lungs are are designed to inhale oxygen, not water. When we inhale the increased moisture content of the air, it can irritate the respiratory system and trigger uncomfortable symptoms.
Fog can be especially irritating when it is mixed with airborne pollutants, allergens or other particles.
Thus, this 'mystery' fog isn't so mysterious after all. People across the US are most likely experiencing a perfectly normal winter weather event, as there is no evidence to suggest otherwise at this time.
