As per the World Health Organization, all but 1% of the world's population is exposed to unhealthy air and also exceeds the WHO limits for pollutants. However, there are some parts of the world where aur quality has improved through policies that limits pollution, while in other parts, it has not reached the desired results.

For US, more than 25% of the population is exposed to "unhealthy" air as per the Environmental Protection Agency (EPA), this is according to the report by the climate non-profit First Street Foundation. By 2050, the number of people exposed to "unhealthy" air will increase by more than half. The worst days of air pollution, reports BBC, "hazardous" or maroon under the EPA's system will rise by 27%.

Why are we talking about this today? It is because of the recent wildfire in California, which started on January 7. This is also one of the factors that is spiking the PM2.5 levels. It has increased by up to five micrograms per cubic metre in the western US in the past decade.

What is PM2.5?

It is a type of air pollution which is made of particulate matter and measures 2.5 micrometres across or less. It is roughly 30 times smaller than the width of a human hair. These particles are made with a mixture of solid and liquid substances, which varies in their chemical composition, including carbon, metals, and organic compounds.

These specks of airborne soot, dust and other substances can also trigger inflammation, which could also damage your brain.

As per a 2021 study titled The Changing risk and burden of wildfire in the United States, a quarter of US's PM2.5 pollution was caused by wildfire smoke. In 2023, US also witnessed a significant dip in air quality and visibility as smoke from wildfires north of the Canadian border entered across the continent. In May 2024, Canada also saw a start to its wildfire season, and one town was evacuated in British Colombia.

Wildfire smoke and its effects

Wildfires do not only affect those who live near forests, peatlands, and grasslands, but also to the cities and environment in general. It can send plumes up to 14 miles or 23km into the stratosphere, and from there, it can spread all over the globe. For instance, in 2023, the Siberian wildfires released smoke that travelled across the Pacific Oceans to reach Alaska and Seattle.

Other than PM2.5, wildfire smoke is also harmful to immune cells in lungs, and the toxicity could be four times greater than particulates from other types of pollution.

Another 2019 study titled Effects of Atmosphere Processing on the Oxidative Potential of Biomass Burning Organic Aerosols found the toxicity of smoke doubled in the hours after it was first emitted and reached four times greater toxicity at its peak.

Health Impact

There have been research that shows how pollution affects your brain. It can lead to impaired judgment, poorer performance in school and even higher levels of crime, as per the 2018 study by the London School of Economics.

Other health concerns include weight gain. There have been researches that links airborne pollution such as PM2.5 to obesity. The studies have found that children who live in most polluted areas are twice as more likely to have obesity. Some studies also find the link of air pollution harming our sense of smell. As per an Italian study from 2022, titled Association between environmental air pollution and olfactory functioning among Italian adolescents and young adults in Northern Italy, noses of teenagers and young adults became less sensitive to odors after being exposed to nitrogen dioxide, which is a component in traffic fumes.

Parkinson's disease is a progressive, neurodegenerative movement disorder caused by the loss of dopamine-producing brain cells, primarily affecting people over 60. Apart from motor loss, the disease also causes cognitive decline, depression, anxiety and swallowing problems.

The first symptom may be a barely noticeable tremor in just one hand or sometimes a foot or the jaw. Over time, swinging your arms may become difficult and your speech may become soft or slurred. The disorder also causes stiffness, slowing of movement and trouble with balance that raises the risk of falls.

However, before clear symptoms begin to appear, Neurologist Rachel Dolhun says certain signs may help identify the onset of the disease decades before it is diagnosed.

“It’s important to stress that not everyone who has these symptoms goes on to develop Parkinson’s,” said neurologist Rachel Dolhun. “But we know that in some people, these can be some of the earliest signs," she told The Washington Post.

Here is what you should look out for:

1. Loss Of Smell

Loss of smell, or hyposmia, is a common and early non-motor symptom of Parkinson's disease, affecting up to 90 percent of patients. This symptom can significantly impact quality of life by reducing the enjoyment of food and diminishing appetite.

While strongly linked to Parkinson's, smell loss can also stem from other causes, including sinus problems, COVID-19, or aging.

2. Acting Out Dreams

Acting out dreams, known as REM Sleep Behavior Disorder (RBD), involves physically enacting vivid, often unpleasant dreams through shouting, punching, or kicking during sleep.

This typically happens because the brainstem fails to temporarily paralyze muscles during REM sleep. It is a strong early warning sign of Parkinson's disease, often appearing years or decades before motor symptoms. About 50 percent of people with Parkinson's experience RBD.

READ MORE: Parkinson’s Patients May Soon Walk Better With This New Personalized Brain Therapy

3. Constipation

Constipation is a very common and significant non-motor symptom of Parkinson's disease that is caused by nerve changes slowing gut muscles and potentially exacerbated by low activity and dehydration.

Constipation can also be caused by Parkinson's medications such as anticholinergics, amantadine and other common drugs such as opioids, iron/calcium antacids.

4. Dizziness As You Stand

The autonomic nervous system fails to properly constrict blood vessels or increase heart rate upon standing, often due to a lack of norepinephrine. This causes the autonomic nervous system to fail in regulating blood pressure. Over time, this leads to Neurogenic Orthostatic Hypotension.

Beyond dizziness, symptoms include blurred vision, weakness, fatigue, cognitive "fog," and "coat hanger pain" (pain in the neck/shoulders). Often times, patients experience dizziness in the morning or immediately after meals.

Diagnosing Parkinson’s disease is mostly a clinical process, meaning it relies heavily on a healthcare provider examining your symptoms, asking questions and reviewing your medical history. Various imaging and diagnostic tests used to detect disease includes CT scan, PET scan, MRI scan and genetic testing.

Beyond icy roads and fogged-up car windscreens, the coldest season can also bring on a painful condition that leaves the skin covered in red, itchy patches. Doctors have issued a warning about this lesser-known illness, which tends to worsen in low temperatures.

The condition, known as cold urticaria, affects around one in 2,000 people. It causes swelling and itching of the skin when it comes into contact with cold air, cold water, or even air conditioning. Red welts or hives can appear within minutes, and the discomfort may last for as long as two hours.

What Is Cold Urticaria?

Cold urticaria is an uncommon condition in which the body reacts abnormally to cold temperatures. It typically causes rashes or hives after exposure to cold air, water, food, or drinks. In some cases, symptoms can be more serious. According to the Cleveland Clinic, the condition may sometimes be linked to an underlying blood cancer or an infectious illness.

Griet Voet, head of a dermatology clinic in Ghent, Belgium, as per Express UK, said the condition is often confused with common winter skin problems such as eczema. “This is not just dry skin caused by cold weather, it is a genuine allergic reaction to cold,” she explained. In more severe cases, large areas of the body may be affected, particularly after swimming in cold water or spending extended periods outdoors. This can lead to intense itching, facial flushing, and even headaches, stomach pain, or fainting. Sudden temperature shifts, such as moving from a warm indoor space into cold outdoor air, can also trigger symptoms. Drinking ice-cold beverages may cause swelling of the lips, mouth, or throat.

Cold Urticaria: What Are The Symptoms Of This Disease?

Symptoms of cold urticaria differ from person to person and can range from mild to severe. They may be limited to a small patch of skin or spread across the entire body.

The most common sign is a skin rash that appears after contact with something cold. The rash usually develops once the exposure ends, as the skin begins to warm up.

The rash may include:

• Hives, bumps, or raised welts
• Itching
• Redness
• Swelling

• Fatigue
• Fever
• Headache
• Joint pain

• Fainting
• Heart palpitations
• A severe allergic reaction known as anaphylaxis
• Shortness of breath or wheezing

How Is Cold Urticaria Diagnosed?

A medical professional can often diagnose cold urticaria using a simple test. An ice cube is placed on the skin, usually on the arm, for a few minutes and then removed. If a hive or rash appears several minutes later, the result is considered positive.

In cases of familial cold urticaria, diagnosis may involve exposure to cold air for a longer duration.

Doctors may also suggest blood tests to check for any underlying illness or infection that could be contributing to the condition.

Health authorities have urged the public to stay alert to Nipah virus symptoms after doctors warned that up to 75 per cent of infected patients may not survive. The UK Health Security Agency (UKHSA) has classified Nipah as a “high priority pathogen” because of its severe fatality rate and the absence of any proven treatment.

In India, the federal health ministry has confirmed two cases in the eastern state of West Bengal. This has triggered large-scale containment measures, with local officials placing nearly 200 people who had contact with the infected individuals under quarantine.

Also Read: Vitamin D Supplements Under Scrutiny As It Fails Safety Test

In response, several Asian nations have stepped up airport checks and health surveillance for travellers arriving from India. Professor Paul Hunter, an infectious disease specialist at the University of East Anglia, said identifying Nipah cases at borders is challenging, as symptoms can take a long time to appear.

What Is Nipah Virus?

According to UKHSA, Nipah virus is a zoonotic infection, meaning it can pass from animals to humans. It can also spread through contaminated food or via direct human-to-human contact. The virus was first discovered in 1999 during an outbreak affecting pig farmers in Malaysia and Singapore.

Fruit bats, especially those belonging to the Pteropus species, are the virus’s natural carriers. Research shows that Nipah can also infect other animals, such as pigs, dogs, cats, goats, horses and sheep.

Nipah Virus Symptoms

• Sudden onset of fever or general flu-like illness
• Development of pneumonia and other breathing-related problems
• Swelling or inflammation of the brain (encephalitis) or meningitis

Symptoms usually appear between four and 21 days after exposure, although longer incubation periods have occasionally been reported. More severe complications, including encephalitis or meningitis, can develop between three and 21 days after the initial illness begins.

Also Read: Nipah Virus Outbreak In India: All That You Need To Know About This Infection

Nipah Virus Symptoms Explained As Doctors Warn 75% Fatality Rate

UKHSA has cautioned that between 40 and 75 per cent of people infected with Nipah virus may die. Those who survive can experience long-term neurological effects, such as ongoing seizures or changes in behaviour and personality. In rare instances, the virus has been known to reactivate months or even years after the first infection.

Nipah Virus: Can You Prevent It From Spreading?

For people travelling to regions where Nipah is known to occur, prevention largely involves reducing exposure risks:

• avoid contact with bats, their habitats, and sick animals
• do not drink raw or partially fermented date palm sap; if consuming date palm juice, make sure it has been boiled
• wash all fruits well with clean water and peel them before eating; avoid fruits found on the ground or those that appear partly eaten by animals
• use protective clothing and gloves when handling sick animals or during slaughter and culling
• maintain good hand hygiene, especially after caring for or visiting ill individuals
• avoid close, unprotected contact with anyone infected with Nipah virus, including exposure to their blood or bodily fluids

Nipah Virus Symptoms Can Be Transmitted Easily?

Many Nipah infections have been linked to eating fruit or fruit-based products contaminated by the saliva, urine or droppings of infected fruit bats. Human-to-human transmission can also occur through close contact with an infected person or their bodily fluids, according to Mirror.

Such transmission has been documented in India and Bangladesh, with cases often involving family members or caregivers tending to infected patients. At present, there is no specific, proven treatment for Nipah virus infection, and no licensed vaccine is available to prevent it.

So far, no Nipah virus cases have been reported in the United States or the United Kingdom.