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.

In a recent post, Dr Sudhir Kumar shared the case of a five-year-old Rishi, a seemingly healthy boy, who suddenly started showing symptoms of deafness and even vision loss. However, the problem wasn’t as surface level as it seemed, as the boy’s brain health was the root cause.

Dr Sudhir Kumar, a Bangalore-based neurologist, shared the rare neurological case of Landau-Kleffner syndrome, he encountered in a five-year-old on the social media platform X.

What is Landau-Kleffner Syndrome?

According to John Hopkins Medicine, Landau-Kleffner Syndrome is a rare nervous system disorder that can cause the loss of ability to understand and use language.

They explain that it can happen to a child who has been developing normally and can also cause seizures. It can happen over time or even suddenly.

But what causes it and is it treatable? The condition is treatable with speech therapy and medication; however, not much is known regarding what causes it.

Researchers say it could be caused by mutation in the genes or the immune system attacking its own tissues like an autoimmune disorder.

Can A Child Stop Hearing Out Of The Blue?

While the first 3 years of Rishi’s life was on track with the development of an average child, things quickly changed.

He stopped looking up when his name was called and acted as if he couldn't hear at all. His parents took him to ear specialists, but the tests showed his ears were perfectly healthy. Over the next year, Rishi stopped speaking entirely and was eventually labeled as "deaf and mute."

Dr Sudhir explained that the timeline of his symptoms didn't match typical deafness. Most children who can't hear are born that way; they don't usually start talking and then suddenly stop.

This suggested that Rishi hadn't lost his hearing, he had lost his ability to understand sound. To solve the mystery, the doctor ordered a sleep EEG to monitor Rishi’s brain waves overnight.

What Are The Symptoms Of Landau-Kleffner Syndrome?

The symptoms of Landau-Kleffner Syndrome can be confusing because they often look like hearing loss or autism. Based on Rishi’s experience, the main signs include:

• Word deafness, which means that the child might hear a sound (like a bell) but cannot understand spoken words.

• Loss of speech is one of the main symptoms of this condition. As the child stops understanding language, they eventually stop speaking the words they once knew.

• Behavioral changes like the children may become frustrated or seem unaware of their surroundings.

• Hidden seizures could also be a symptom. While some children have physical seizures, many (like Rishi) only have abnormal brain activity during sleep.

Is Landau-Kleffner Syndrome Treatable?

The most important takeaway for Rishi’s family was that LKS is treatable. Because it is caused by abnormal electrical activity, doctors can use anti-seizure medications to "calm" the brain. Once Rishi started his treatment, the results were life-changing.

After three months, he began responding to his name again. Within six months, he was talking, playing, and laughing just like any other child. The "silence" in his home was finally gone.

Rishi’s story is a reminder that when a child suddenly loses language skills, every second counts. If LKS is caught early, the brain has a much better chance of recovering and rewiring itself.

If left untreated for too long, the loss of speech could become permanent. By understanding that the problem was in the brain and not the ears, Rishi’s doctors were able to give him his future back.

Hearing is one of the most vital yet overlooked senses—and its impact extends far beyond the ears. It shapes how a child learns to speak, how a student performs in school, how adults stay socially connected, and even how the brain ages.

As Dr NVK Mohan, ENT and Cochlear Implant Surgeon at CK Birla Hospitals, CMRI, explains, “Hearing is one of the most vital yet overlooked senses, and its impact extends far beyond the ears.”

This World Hearing Day, the focus is clear: ignoring hearing loss doesn’t just affect sound—it affects development, confidence, learning, and long-term brain health.

What Is Hearing Loss?

Hearing loss can happen when any part of the ear is not working in the usual way. This includes:

• The outer ear
• The middle ear
• The inner ear
• The hearing (acoustic) nerve
• The auditory system in the brain

When sound cannot travel properly through these structures—or when the brain cannot process sound clearly—hearing becomes impaired. It may be partial or complete, temporary or permanent, and can occur at any stage of life, from before birth to adulthood.

In Children: The Impact Goes Beyond the Ears

In children, hearing plays a central role in speech and language development. Even mild hearing loss can cause a child to miss critical sounds needed to build vocabulary and clear speech.

Dr Mohan notes, “In children, undetected hearing loss can interfere with speech development, learning ability, and social interaction, often affecting confidence and academic performance well into adulthood.”

Many parents assume that if a child responds to loud sounds, their hearing must be normal. But hearing is more complex than that.

“Healthy hearing requires the ability to perceive sounds across all frequencies, especially those essential for speech and language development,” he explains. “Delayed identification can mean missed developmental milestones that are difficult to recover later.”

Signs of Hearing Loss in Babies

Even if a baby has previously passed a hearing screening, parents should continue to look for warning signs:

• Does not startle at loud noises
• Does not turn to the source of a sound after 6 months of age
• Does not say single words like “mama” or “dada” by 1 year
• Turns head when seeing you but not when you call their name
• Seems to hear some sounds but not others

What may look like inattention can sometimes be partial or complete hearing loss.

Signs of Hearing Loss in Children

As children grow, signs may include:

• Delayed speech
• Unclear speech
• Difficulty following directions
• Frequently saying “Huh?”
• Turning the TV or radio volume up too high

Babies and children are expected to reach developmental milestones in how they play, learn, communicate, and behave. A delay in these areas could indicate hearing loss or another developmental concern—and should prompt a hearing evaluation.

What Causes Hearing Loss?

Hearing loss can occur at any time during life.

Genetic Causes

About 1 in 2 cases of hearing loss in babies are due to genetic factors. Some babies may have family members with hearing loss. Around 1 in 3 babies with genetic hearing loss have a syndrome, meaning they have additional conditions such as Down syndrome or Usher syndrome.

Other Risk Factors

Around 1 in 4 cases are linked to:

• Maternal infections during pregnancy
• Complications after birth
• Spending 5 days or more in a neonatal intensive care unit (NICU)
• Severe jaundice requiring blood transfusion
• Structural differences in the head, face, or ears
• Neurological disorders
• Meningitis
• Severe head injuries requiring hospitalization

Recognizing these risks allows for closer monitoring and earlier diagnosis.

In Adults: When Hearing Loss Affects the Brain

The consequences of untreated hearing loss do not stop in childhood. In adults and older individuals, the risks shift from speech delays to brain health.

Dr Mohan highlights, “In adults and the elderly, untreated hearing loss is increasingly being linked to social withdrawal, memory problems, and cognitive decline.”

When the brain does not receive clear sound input, it must work harder to interpret speech.

“When the brain is deprived of clear sound input, it has to work harder to interpret speech, diverting cognitive resources away from memory and higher mental functions,” he explains. “Over time, this reduced auditory stimulation and social disengagement can increase the risk of accelerated cognitive ageing.”

In simple terms, when hearing decreases, conversations become exhausting. People may begin to withdraw socially. The brain receives less stimulation. Over time, this combination can affect cognitive resilience.

Hearing health, therefore, is closely linked to brain health.

Prevention: What Can Be Done?

While not all hearing loss can be prevented, certain measures reduce risk:

• Maintain a healthy pregnancy
• Ensure children receive recommended vaccinations
• Protect children from high noise levels
• Seek prompt treatment for ear infections

Noise-induced hearing loss, in particular, is preventable with awareness and protection.

Screening and Early Diagnosis: The Most Important Step

The most important message, experts say, is that hearing loss is both detectable and manageable—especially when addressed early.

“Hearing screening is easy and not painful. Babies are often asleep during the test, and it usually takes only a few minutes,” Dr Mohan says.

For Babies

• All babies should undergo hearing screening by 1 month of age.
• If a baby does not pass, a full hearing test should ideally be completed by 3 months.

For Children

• Hearing should be tested before school entry.
• Testing should also be done whenever there are concerns about speech delay, learning difficulties, or recurrent ear infections.
• Routine hearing checks are equally important for adults, particularly as they age.

Vaccinated for human papillomavirus (HPV)? Now, take that Pap smear test. This is the most common advice women hear to prevent the risk of cervical cancer that annually causes around 6,60,000 new cases and around 350,000 deaths worldwide.

However, it's easier said than done for most of the fairer sex.

A Pap smear is typically a gynecological examination where a speculum is inserted to collect cells from the cervix.

Although the procedure is brief and generally safe, the discomfort discourages many from getting screened. Fear of pain, anxiety of the results, form the common psychological barriers worldwide, and is followed by shame, cultural attitudes, and concerns with male clinicians.

A study in Iran, published in the BMJ Open journal in January 2024, showed that psychological stress, cultural issues, and fear, along with limited information and health services, were the biggest hindrances to getting Pap tests.

Another research published in the BMC Women's Health in December 2022, focusing on Africa, Asia, and South America, reported that many women avoided or delayed Pap smears because they are afraid the procedure will hurt. Many also reported being embarrassed about the pelvic exam or fear of having a stranger see their private areas. Some also worried that the test could damage the uterus.

A Pap Smear test, however, is proven to be safe and is recommended for every woman above the age of 21 years.

“A Pap smear is a rapid, safe, and painless screening procedure that detects irregular cellular changes well before they become malignant. The ability to treat at this pre-cancerous stage of disease provides an excellent outcome,” Dr. Tirathram Kaushik, Senior Consultant GI, HPB, Gastrointestinal & Thoracic Oncology and Robotic Surgery, HCG Cancer Centre, Borivali, told HealthandMe.

A 2025 study, published in the Journal of Contemporary Clinical Practice, showed that pap smears are excellent at ruling out precancerous risks. It also remains a valuable screening tool where molecular testing is limited.

There are many myths about Pap smears that make people anxious or avoid screening. Let’s clear up the most common ones:

Pap Smears Are Painful

The Pap smear procedure, which takes only a few minutes, is often described as uncomfortable. While some feel like a quick pinch, others experience slight discomfort or spotting. Severe pain is not considered normal.

“From an oncology perspective, this myth results in a delay in diagnosis. Cervical cancer often occurs silently in its early stages, without any noticeable symptoms,” Kaushik said.

I Am Healthy, So I Don’t Need A Pap Smear

While individuals may feel completely well, they still have abnormal cells developing silently. As a result, regular Pap smear screening is important because it detects these changes early -- before they turn into cervical cancer.

“The HPV infection and subsequent changes that lead to cervical cancer happen slowly over many years. HPV infection is also very common, and one in two women is likely to get infected. Regular screening by a Pap smear will help to catch infection early before it can convert into cancer,” Dr. Deepak Jha, Chief - Breast Surgery & Sr. Consultant Surgical Oncology, Artemis Hospitals, told HealthandMe.

I Have Only One Partner, So I Don’t Need Screening

“HPV doesn’t need penetrative sex for infection. It can be transferred if there is any contact of bodily fluid. It’s always safe to test and be assured rather than repent later,” Dr. Jha said.

Testing Means Cervical Cancer

“Even if HPV is detected, it usually indicates a pre-cancerous stage that is highly treatable,” Dr. Parminder Kaur, Consultant Gynecologic Oncologist at CK Birla Hospital, Delhi, told HealthandMe.

Moreover, a Pap smear only screens for cervical cancer; it can’t detect other gynecological cancers such as cervical, ovarian, uterine (endometrial), vaginal, and vulvar cancers. So, screening and appropriate tests for those will be required, irrespective of the Pap smear.

I Am Old, So I Don’t Need A Pap Smear

I Got Vaccinated, So I Do Not Need A Pap Smear

Irrespective of vaccinated status, a woman should go for regular screening between the ages of 25 and 79. Also, if a woman already had HPV exposure before being vaccinated, she would not benefit, the experts said.

“Screening is not just a routine procedure - it is a preventive measure. In the treatment of cancer, early detection alters the disease course, whereas waiting for symptoms to develop means the disease is likely to be already advanced,” Dr. Kaushik said.

Dr Kaur called for more awareness and stated that open discussion are key to help more women take the important screening test.

When To Get Screened

The United States Preventive Services Task Force (USPSTF) and the American Cancer Society (ACS) recommend getting your first Pap test at age 21, followed by Pap testing every 3 years. Even if you are sexually active, you do not need a Pap test before age 21.

• Individuals must start getting Pap tests at age 21. If the result is normal, repeat the test after three years.
• For individuals aged between 30 and 65 years old, doctors are likely to recommend an HPV test along with a Pap test. If both are normal, repeat after five years.

In women older than 65, you don't need to be screened anymore if:

• You have had at least three Pap tests or two HPV tests in the past 10 years, and the test results were normal or negative, and
• You have not had a cervical precancer in the past, or
• You have had your cervix removed as part of a total hysterectomy for non-cancerous conditions, like fibroids.