Mysterious Fog in the US , Canada and UK: A dense, eerie fog with a "burning chemical-like smell" has spooked a good part of North America and parts of the United Kingdom and Canada. With social media amplifying all concerns, this phenomenon has sparked attention across all social media platforms. However, at the heart of this mysterious fog are a conjunction of natural events, social psychology, and environmental conditions that culminated in all the conspiracy theories and public health fears. Here's a closer look at the mysterious fog, its potential causes, and the societal response it has triggered.

Fog that Feeds Fear

The first reports of this "mysterious fog" came in from Florida where a resident said that they experienced respiratory symptoms, feverish warmth, and stomach cramps after contact with the fog. Similar stories started flooding social media, and within a day or two, a sinister force seemed to sweep across the United States, Canada, and parts of the UK. From Texas to Minnesota, people reported weird odors and health issues that they thought were linked to this bizarre atmospheric event.

Some witnesses were said to see "white particles" swirling through the air; theories ranged from a chemical attack or experimental weapon to drone-related chemical dispersals and references to historical military experiments, such as the infamous 1950s "Operation Sea-Spray."

Fuel to the fire were added when videos and posts, hundreds of thousands in number, began circulating on social media sites like TikTok and X (formerly Twitter) speculating on the origin of the fog. Hashtags like #ToxicFog went trending for days. Hysteria created a self-reinforcing loop in which every post spurred further scrutiny and fear.

Scientific Explanation of the Dense Mysterious Fog

1. What is Fog?

Fog is essentially a low-lying cloud formed when the air temperature cools to its dew point, causing water vapor to condense into tiny droplets or ice crystals. Several types of fog—advection fog, radiation fog, and valley fog—can form depending on conditions such as warm, moist air moving over cooler land or when temperatures plummet rapidly under clear skies.

2. Why the Chemical Smell?

Such chemical-like smell as reported during the occurrence of fog events is sometimes attributed to air pollution. It acts like a sponge, where it absorbs these pollutants, which include sulfur dioxide and nitrogen oxides, among others, that emit from industries. This mixture, therefore, leads to a stench that could be mistaken as unnatural or even toxic.

Also Read: Health Concerns Rise As US, Canada, and UK Come Under The Blanket Of Thick, Dense, Toxic Fog

3. What are the Health Concerns?

High moisture levels from fog can significantly exacerbate symptoms related to respiration, but especially in already predisposed asthmatics and allergy patients. The connection of these symptoms with actual fever, stomach cramps, and puffy eyes is too remote. Experts assume that the irritating effects of entrapped pollutants trapped in fog tend to affect more the eyes and throat rather than the rest of the body affected by some report.

Psychological Effects of Mass Panic Caused by Social Media

Social media amplified a natural weather event into a health epidemic. It made the personal experience of individuals become a cause for fear and speculation, a domino effect.

According to psychologists, this is a concept of selective perception, wherein once people's attention is drawn to environmental anomalies, they begin to notice them. This mirrors earlier panics, such as the Seattle windshield pitting panic of 1954. Then, atomic bomb testing caused fear in many and started to have people looking at their windshields for small marks that they had not seen before. Likewise, postings on the strangeness of the fog probably increased public awareness and suspicion, with people looking to attach unrelated symptoms to the phenomenon.

The fog hysteria shares a commonality with other instances of mass panic, such as the "drone sightings" of recent years or the Cold War-era fears of biological warfare.

Also Read: Mysterious Fog Is Making Americans Sick

These events underscore how fear can cloud judgment, especially when amplified by social media and sensationalist headlines. While historical cases, such as "Operation Sea-Spray," offer concrete evidence of the existence of unethical experiments, the jump from a natural weather condition to theories of chemical attacks exemplifies a more modern trend of connecting unrelated dots, all wonderfully seeded in distrust and anxiety.

Despite the swirling rumors, meteorologists and scientists are in agreement that the mysterious fog is not as alarming as it seems. It is well known that fog traps and amplifies pollutants, especially in urban and industrial regions. Moreover, winter months are the most conducive for fog formation, so its recent prevalence is unsurprising.

On the other hand, environmentalists advise that the fog should wake everyone up to increased levels of pollution. The reported odors and health irritations could be just symptoms of far deeper systemic issues like industrial emissions and lack of control over air quality.

The authorities must be transparent in their communication to combat misinformation and allay public fears. Governments and environmental agencies must provide timely updates on weather phenomena, air quality, and health risks. Initiatives like real-time pollutant tracking and public education campaigns can help demystify natural occurrences while addressing valid environmental concerns.

The mysterious Canada fog is a compelling case study in how environmental events intersect with psychology and societal dynamics. While rooted in natural phenomena, the fog became a vessel for collective fears, amplified by modern technology and historical anxieties.

In this information era where communication occurs at an almost lightning pace, the fog becomes a metaphor that reminds everyone about scientific literacy, environmental responsibility, and an effective balance when considering public concern. Whether perceived as a marvel of nature or as a tale that serves to teach, it left a very powerful mark in people's minds.

Adenovirus, or what some people are calling the mystery disease is going to be the next worry in the UK, after superflu had already grappled the healthcare system. Along with H3N2 and its variant superclade K, people are now worrying about this mystery disease.

Adenovirus is highly contagious and causes mild cold or flu-like symptoms, though severe cases could lead to stomach flu and vomiting. Many describe this virus as 'heartier' than others. The reason is that the virus can survive longer on surfaces and even resist the common disinfectants used. This is what makes it highly transmissible.

Is There Any Treatment For Adenovirus?

As of now, there is no treatment for adenovirus, it could however be managed and monitored. What helps is regular handwashing and thorough cleaning of surfaces.

The good news is that cases of adenovirus are actually dropping in the UK, as confirmed lab reports. The cases last week were 1.2 per cent, whereas the week prior, it was at 1.7 per cent, as also reported by the Independent.

What Are The Symptoms Of Adenovirus?

While a lot of the symptoms mimics of those in flu or COVID, including shortness of breath, a sore throat and or a runny nose. However, there are certain unique symptoms of adenovirus that include:

• Diarrhea
• Pink Eye or conjunctivitis
• Ear infection or otitis media
• Swollen lymph nodes
• Pneumonia
• Stomach pain
• Nausea
• Vomiting

Other rare symptoms could also include impact on your bladder or nervous system. As viruses in your bladder can also cause urinary tract infections, and the same virus in your nervous system can cause condition that can affect your brain. These conditions also include encephalitis and meningitis.

The symptoms usually start to subside within two days, however, if the symptoms stay even after three days without any relief, it might be a red flag. The best thing to do during such a situation is to go consult your GP.

Also Read: Unique Symptoms Of Mysterious Adenovirus And How Long Infection Now Last

Is Adenovirus Spreading Faster Than Flu and Covid?

Experts have noted that due to its ability to stay longer in the environment and being highly transmissible, it is in fact, spreading faster than flu and COVID. Eric Sachinwalla, Jefferson Health's medical director said that this virus is still unfamiliar and thus not much can actually be done to treat adenovirus. Speaking to PhillyMad, he said, "It is pretty contagious because it is heartier than other viruses - soap and water, or everyday disinfectant, won't kill it, so it tends to live in the environment longer."

What Are The Ways To Stay Safe From Adenovirus?

Since adenovirus spreads through close contact and is resistant to many everyday disinfectants, hygiene remains the key. The best way to stay safe is by avoiding close contact, especially with those who are unwell. You may also keep an eye on your symptoms, including your body temperature and take steps to prevent the virus from spreading by taking precautions, as well as getting the flu jab.

The World Health Organization (WHO) on December 24 prequalified two rapid antigen diagnostic tests (Ag-RDTs) for SARS-CoV-2. This virus is known to have caused COVID-19. As per the WHO, these two tests are called SD Biosensor STANDARD Q COVID-19 Ag Test and the ACON Biotech Flowflex SARS-CoV-2 Antigen Rapid Test (Self-Testing).

At first these tests got temporary emergency approval from the WHO during the pandemic. This was done so the countries could start using them quickly even though long-term data was limited. This emergency approval helped the tests reach over 100 countries when they were urgently needed.

What Has Changed Now?

The WHO has now given these tests full prequalification, which means it has a stronger and long-term approval. This means that the WHO has thoroughly checked and confirmed that the tests consistently meet global standards for quality, safety, and accuracy.

Why Does This Matter?

• The tests can now be officially bought and used by global organizations and governments
• They can be included in bulk purchasing to lower prices and increase supply
• This makes reliable COVID-19 testing more affordable and accessible, especially in low-and middle-income countries

COVID-19 Is Far From Being Over

Even though WHO officially ended COVID-19 emergency phase over two years ago, the virus is still circulating globally. In fact, this year, we have seen variants of COVID-19 circulating around, causing the most unique symptoms, including razor-blade like throat. Variants like JN.1, Stratus, Nimbus, LP8.1, and BA.3.2 were all that we saw in 2025.

While the good news is that infection levels are relatively stable, but the virus has not completely disappeared and testing is still necessary, especially in poorer countries.

Many low-income countries do not have easy access to labs or expensive PCR testing. So there is still a need for a strong, but cheaper and reliable way to detect COVID-19, and these tests may as well do that.

Why Rapid Antigen Test Matters

• Give results in 15–30 minutes
• Cost less than PCR tests
• Don’t require labs or specialized equipment
• This means they can be used in small clinics, community centers, mobile vans, or remote areas, where lab testing isn’t practical.

However, it is important to note that rapid antigen tests are not replacement for PCR tests. They simply complement the PCR tests by allowing faster, on-the-spot decisions, especially when the lab capacity is limited.

What Makes It Essential Today?

Rapid antigen tests could help with spotting and stopping local outbreaks quickly, protecting high-risk people and healthcare workers, and staying prepared for future respiratory pandemics.

The WHO is also pushing for decentralized, quality-checked testing as part of universal healthcare and global health security, so countries aren’t caught unprepared when the next outbreak happens.

When Is It A Right Time To Get Yourself Checked For COVID-19?

If you notice these following symptoms as noted by the Centers for Disease Control and Prevention (CDC), it is best that you get yourself a COVID-19 test:

• Fever or chills
• Cough
• Shortness of breath or difficulty breathing
• Sore throat
• Congestion or runny nose
• New loss of taste or smell
• Fatigue
• Muscle or body aches

As Delhi's air quality levels and pollution continues to worsen, and people struggle to breathe, countries like Singapore, the United Kingdom, and Canada issued advisories for their citizens travelling to the capital city. However, the capital city's crisis continues to remain ignore, though CM Rekha Gupta did hold a review meeting on the same on Monday, with a follow-up scheduled on Thursday.

Singapore Travel Advisory On Delhi's Air Pollution

Singapore High Commission issued an advisory, which stated:

On 13 December 2025: The Indian Central Pollution Control Board invoked Stage 4, the highest level, of the Graded Response Action Plan (GRAP) in the Delhi National Capital Region. Under GRAP 4, construction and industrial activities are heavily restricted, and schools and offices are encouraged to shift to hybrid format. The Delhi authorities have urged residents to stay indoors, especially children and those with respiratory or cardiac ailments, and to use masks if stepping out. In this regard, the High Commission urges Singapore nationals in the Delhi National Capital Region to pay heed to this advice.

We also note that given the low visibility, flights to and from the Delhi National Capital Region are likely to be affected. The Indira Gandhi International Airport and several airlines have issued advisories. Travellers should take note of this, and check with the respective airlines for updates.

UK And Canada Too Issue Advisories On Delhi Pollution And Its Impact On People

UK's Foreign, Commonwealth & Development Office (FCDO) warned that air pollution could lead to serious health threats for those living in northern India, especially between the months of October and February. The UK advisory also stressed on the health of pregnant women and people with any heart or respiratory. The advisory noted that they must seek medical advice before travelling to India.

The statement read: Children, the elderly and those with pre-existing medical conditions may be especially affected. If you’re pregnant or have a respiratory or heart condition you may wish to consult a medical practitioner before you travel.

Canada too issued a similar notice, advising, especially those who are already struggling with respiratory issues and to continuously monitor air quality levels. The notice also highlighted the pollution that is caused by fog and smoke trends that are increasing in urban areas like Delhi, especially during the winters.

The advisory read: Smoke haze and other types of air pollution can be extremely hazardous in urban areas and cities such as Delhi. It’s typically at its worst in winter. In rural areas, air quality can be affected by agricultural burning. Dust storms also occur across northern India. Monitor air pollution levels, which change quickly, especially if you suffer from respiratory ailments or have pre-existing medical conditions.

As of today, Delhi's air quality remained in "very poor" category, and the AQI stood at 342 at 8am, as per the Central Pollution Control Board. The 24-hour average AQI was logged at 412 under the "severe" category on Tuesday evening when Delhi's quality peaked to record the fourth severe air day in the month of December.