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.

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.

Smoking has long been recognized as one of the most preventable causes of disease and early death worldwide. It plays a major role in heart attacks, strokes and several chronic illnesses. While public health messaging often focuses on how much a person smokes, new research suggests that when someone starts smoking may be just as important for long-term health.

A large nationwide study published in Scientific Reports analyzed health data from over nine million adults in South Korea. The findings were striking. People who began smoking before the age of 20 faced a significantly higher risk of stroke, heart attack and early death compared to those who started later, even if their total lifetime smoking exposure was similar.

Smoking Before 20: Why the age matters

Traditionally, doctors and researchers estimate smoking-related harm using pack-years, which combines the number of cigarettes smoked per day with the number of years a person has smoked. While this remains useful, the new study highlights an important gap. Two people with the same pack-years may not have the same health risks if one started smoking much earlier in life.

The researchers found that early starters had a much higher risk of stroke and heart attack than those who took up smoking after the age of 20. This suggests that the body may be especially vulnerable to tobacco damage during adolescence and early adulthood, making age of initiation an independent risk factor.

Smoking and stroke: what we already know

The link between smoking and stroke is well established. Long-term studies, including the famous Framingham Heart Study, have consistently shown that smokers are far more likely to experience a stroke than non-smokers. The risk increases with the number of cigarettes smoked and affects people across age groups.

Smoking damages blood vessels, speeds up plaque build-up in arteries, raises blood pressure and makes blood more likely to clot. All of these changes increase the chances of both ischaemic and haemorrhagic strokes. Younger adults who smoke are not protected simply because of their age, and in many cases, their relative risk is even higher.

Key findings from the Korean cohort

The study followed participants for nearly nine years using data from a mandatory national health screening programme. Researchers looked at stroke, heart attack, combined cardiovascular events and overall death rates.

Those who started smoking before 20 had about a 78 percent higher risk of stroke compared to non-smokers, especially when they also had high smoking exposure. Early starters also showed a much greater risk of heart attacks and combined cardiovascular events. Importantly, they had a higher risk of death from all causes, not just heart-related conditions. These patterns were consistent across men and women and across different metabolic health profiles.

Why early smoking causes greater harm

There are several reasons why smoking at a younger age may be more damaging. During adolescence, the heart, blood vessels and brain are still developing, which may make them more sensitive to toxins in tobacco smoke. Starting early is also linked to stronger nicotine dependence, making quitting harder and often leading to longer periods of smoking.

Early exposure may also trigger lasting inflammatory and metabolic changes in the body. These changes can increase stroke risk later in life, even when total cigarette exposure appears similar on paper.

What this means for public health

The findings send a clear message. Preventing smoking during adolescence could significantly reduce the future burden of stroke and heart disease. School-based education, strong warning messages and policies that limit youth access to tobacco remain critical.

Delaying smoking initiation, even by a few years, may have lifelong benefits. With cardiovascular diseases already among the leading causes of death globally, protecting young people from tobacco use is not just about avoiding addiction. It is about safeguarding their long-term health.

A simple tennis ball might be able to tell you whether you have dementia or not. While it sounds strange, experts explain that the strength of your hands is a major clue for how well your mind is aging.

In a recent video, Neurologist Dr. Baibing Chen explains that your grip strength is a "window" into your cognitive health. To squeeze your hand, your brain must coordinate nerves, muscles, and blood flow all at once. When this system weakens, it often suggests that the brain’s "resilience" or ability to bounce back is also lower.

While weak hands don't cause dementia, they can be an early warning sign. In some conditions, like vascular dementia, physical changes like slowing down or dropping things often happen before memory loss even begins.

How To Do The Tennis Ball Test At Home?

You don't need expensive equipment to check your strength. You can use a standard tennis ball or a stress ball to track your progress:

Get Ready: Sit up straight with your feet flat on the floor and your arm stretched out in front of you.

Squeeze: Grip the ball as hard as you possibly can.

Hold: Try to keep that strong squeeze for 15 to 30 seconds.

Repeat: Do this three times with each hand and note if you feel tired or if your strength fades quickly.

What the Numbers Mean

Researchers have found that people in the bottom 20% of grip strength have a much higher risk of developing memory problems.

For example, a massive study of nearly 200,000 adults showed that as grip strength drops, the risk of dementia goes up by about 12% to 20%.

Specifically, if a man’s grip strength is below 22 kg or a woman’s is below 14 kg, doctors consider that a "red flag" for future cognitive decline. These numbers are helpful because they show changes in the body years before memory loss actually starts.

What If You Fail The Tennis Ball Dementia Test?

It is very important to remember that a weak grip is not a guarantee of dementia. Many factors, such as arthritis, old injuries, or general lack of exercise, can cause your hands to feel weak.

The goal of this test is not to scare you, but to encourage you to be proactive. If you feel like your hands are getting "tired" faster during daily chores or you are dropping items more often, mention it to your doctor. They can help determine if it is just a muscle issue or something that needs more investigation.

How Is Dementia Diagnosed?

Dementia is one of the most common cognitive conditions in the world. According to the World Health Organization, there were 57 million people living with dementia in 2021, many of whom never had any treatment for it.

Early detection of dementia is an important part of the treatment. While it may not completely cure the disease, it can slow down the progress to help people retain as much of their abilities as possible.

Finding out if someone has Alzheimer’s is not as simple as taking one single test. Doctors act like detectives, gathering many different clues to figure out what is happening in the brain. To make an accurate diagnosis, healthcare providers use a combination of different tools and tests:

Brain Scans

Doctors may use imaging tests like MRI, CT, or PET scans to look at the physical structure of the brain and check for any unusual changes.

Cognitive Tests

There may be cognitive tests that check your recall skills. These are mental puzzles or questions that check your memory, problem-solving skills, and how well you can perform daily tasks.

Lab Work

This can also include blood tests or checking "spinal fluid" to look for specific markers that show up in people with certain types of dementia.

Physical Exams

A neurologist may also check your balance, your senses, and your reflexes to see how well your nerves are working.