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.

COVID-19 and influenza are major causes of illness and death worldwide, particularly in countries like the US and UK. Vaccines can prevent infection or reduce the severity of illness, yet many people struggle to stay up to date due to time constraints or lack of motivation. If you are eligible for both vaccines around the same time, combining them in a single visit can save time and effort.

Doctors suggest that receiving both vaccines at the same visit can be a convenient approach, but a common question arises: which arm should you use? Is it safe to administer both vaccines in the same arm, or is it better to use separate arms?

One Arm or Two: Which One To Use For Both Shots?

Getting both shots in one visit sounds efficient, but you still need to decide whether to use one arm or two. Often, it comes down to personal preference, although sometimes the healthcare provider will make the decision. Is there evidence to guide this choice? Should both vaccines go in the same arm or one in each?

Which Arm Works Best for COVID and Flu Vaccines?

Animal studies suggest that administering the COVID and flu vaccines in the same limb may enhance immune responses. The mRNA COVID vaccines include a built-in immune booster called an ionizable lipid, which is a fatty molecule that protects the mRNA inside the vaccine.

Flu vaccines usually lack an adjuvant, but the built-in adjuvant in the COVID shot could potentially boost the flu vaccine’s immune response if both are given in the same arm.

However, giving two shots in one arm can increase the risk of arm soreness, the most common side effect. To explore this in humans, researchers at the University of Melbourne conducted a randomized controlled trial with 56 healthy adults. The study compared giving the Moderna COVID mRNA vaccine and the CSL influenza vaccine in the same arm versus opposite arms.

Participants were randomly assigned to two groups: the “same arm” group received both vaccines in the non-dominant arm (usually the left arm for right-handed people), while the “opposite arm” group had the COVID vaccine in the non-dominant arm and the flu vaccine in the dominant arm. This setup was chosen because the COVID vaccine is more likely to cause a sore arm compared to the flu shot. Researchers collected blood, saliva, and nasal samples, and participants reported on any side effects.

Same Arm vs. Opposite Arm

The trial found no significant differences in key immune responses, such as neutralizing antibodies, whether the vaccines were given in the same arm or separate arms. Secondary analyses suggested a slightly higher immune response to COVID in the opposite arm group.

Nearly all participants reported mild arm soreness. Those in the same-arm group experienced more tenderness in that single arm, while participants in the opposite-arm group had reactions in both arms, particularly in the non-dominant arm that received the COVID vaccine.

What This Means for You

Overall, receiving both vaccines on the same day, whether in one arm or two, provides strong protection against both infections. Choosing opposite arms may slightly improve immune response and reduce soreness in any one arm, but it comes with two mildly sore arms.

For anyone looking to save time, having both vaccines in the same visit is convenient and effective. Most side effects are mild, making the benefits of dual vaccination well worth it.

A new wave of anti-obesity medications is transforming how people experience hunger. Rather than merely suppressing appetite, these drugs work by gently quieting the brain circuits that constantly drive us to eat.

The obesity medication tirzepatide, marketed as Mounjaro or Zepbound, appears to dampen brain activity linked to food cravings, according to a recent study. Researchers tracked the electrical signals in the brain of someone with severe obesity, who had persistent ‘food noise’ soon after starting the medication.

The study is the first to use electrodes to directly observe how blockbuster GLP-1–mimicking obesity drugs affect brain activity in humans, hinting at how they ease intense food cravings. But how exactly do these weight-loss medications work to reduce the ‘food noise’ in your mind?

We spoke with Dr. Nidhi Khandelwal, a leading Robotic & Laparoscopic Bariatric, Hernia & GI Surgeon | Mumbai MS, FIAGES, FALS (Bariatrics), FALS (Robotics), to understand more.

Can Weight Loss Drugs Suppress Food Craving In Your Brain?

Casey Halpern, a neurosurgeon-scientist at the University of Pennsylvania, and his team did not initially set out to study obesity drugs’ effects on the brain. Their goal was to see if deep brain stimulation—a therapy delivering a mild electrical current directly into the brain, could reduce compulsive eating in people with obesity who did not respond to treatments like bariatric surgery.

For the study, participants had electrodes implanted in their nucleus accumbens, a brain region involved in reward. This area also contains GLP-1 receptors, explains Christian Hölscher, a neuroscientist at the Henan Academy of Innovations in Medical Science, Zhengzhou, China, “so we know GLP-1 influences reward circuits.” The electrodes can both record electrical activity and deliver currents as needed and are already used to treat some epilepsy cases.

For the first two participants, intense food-noise episodes coincided with spikes in low-frequency brain activity, suggesting that these signals could indicate compulsive food cravings.

The third participant, a 60-year-old woman, had just started a high dose of tirzepatide—prescribed for type 2 diabetes—when her electrode was implanted. “We took advantage of this chance because of the excitement around these medications,” Halpern says. In the following months, her urges to binge eat disappeared. “It was remarkable to see the absence of food noise in someone with a long history of cravings,” he adds. “Equally striking was the silence in the nucleus accumbens, as seen in the electrical readings from that area.”

How Do Weight Loss Drugs Help With Food Cravings?

Many people struggling with weight describe a constant ‘buzz’ in their minds, preoccupied with thoughts about their next snack, cravings for sweets, or planning meals even when not hungry. This is often called “food noise.” These medications help quiet that constant chatter.

Dr. Khandelwal explains, “They send signals to the brain similar to what naturally happens after a satisfying meal. People feel full faster, stay satiated longer, and don’t experience the same urge to snack constantly. The mind feels clearer, and the emotional pull of comfort foods becomes easier to manage.”

She also noted another benefit: the ability to make better food choices, like selecting a healthier meal or stopping when full. Goals that once felt impossible now feel achievable and more natural. For many, the biggest change is not only weight loss but also the relief of finally having mental peace from constant cravings, which supports healthier habits.

However, Dr. Khandelwal emphasizes that these medications should only be used under the supervision of a specialist in obesity management.

Nearly one in seven couples struggles with infertility, meaning they haven’t been able to conceive despite having regular, unprotected sex for a year or more. In roughly half of these couples, male infertility is at least partially responsible. Causes can range from low sperm production and abnormal sperm function to blockages that prevent sperm delivery.

Illnesses, injuries, chronic conditions, lifestyle factors, and other influences may contribute. Not being able to conceive can be stressful and emotionally challenging, but a variety of treatments exist for male infertility. But are there natural ways to improve male fertility? We spoke with Dr. Ruchi Jain, Fertility Specialist at Nova IVF Fertility, Kolkata, to get her insights.

What Is Male Infertility?

Male infertility refers to a man’s inability to cause pregnancy in a fertile female partner, often due to problems with sperm production, function, or delivery. After a year of trying (or six months if the woman is over 35) without success, doctors usually examine both partners. About 50% of infertility cases involve male factors, with the most common issues being low sperm count (oligospermia), poor motility, abnormal morphology, or the complete absence of sperm in the ejaculate (azoospermia), Dr Jain explained. Some causes are temporary, some treatable, and some may be permanent.

Can Male Infertility Be Treated Naturally?

Many men experience noticeable improvement by focusing on lifestyle changes and addressing reversible medical conditions. Research shows that a nutritious diet (like a Mediterranean-style or “prudent” diet), regular moderate exercise, quitting smoking, reducing alcohol, losing excess weight, and avoiding heat or tight underwear can improve sperm quality.

Dr. Jain noted, “These adjustments don’t guarantee conception, but they often enhance sperm count, motility, and DNA quality enough to support natural conception or assisted reproductive techniques.”

Medical Fixes That Can Restore Fertility

Certain medical conditions that cause infertility can often be reversed. For example, varicoceles, which are enlarged veins in the scrotum—are a common cause; repairing a significant varicocele frequently improves semen parameters and can lead to pregnancy.

Hormonal issues, such as low testosterone or pituitary disorders, may also be treated with medication. Dr. Jain said, “Temporary causes like infections, medications, or recent fevers can lower sperm counts, which often normalize within a few months once the underlying issue is resolved. Professional guidelines highlight that many male-factor infertility cases can respond well to medical or surgical treatment.”

Is Male Infertility Permanent?

Dr Jain told us that some conditions are extremely difficult or impossible to “cure.” Genetic disorders (like Klinefelter syndrome), congenital absence of the vas deferens, severe testicular failure, or damage from chemotherapy or radiation usually prevent normal sperm production.

In these cases, treatment focuses on alternatives: retrieving sperm directly from the testicles, using IVF with ICSI (intracytoplasmic sperm injection), donor sperm, or adoption. Recent studies show that sperm retrieval after certain procedures can improve success rates, but outcomes depend heavily on the underlying condition of the testicles.

What About Supplements, Herbs, and “Natural” Cures?

Interest in antioxidants (vitamins C and E, zinc, L-carnitine), herbal remedies (maca, ginseng), and bioactive compounds (resveratrol, curcumin) is rising. Some research reports modest improvements in sperm quality, while other studies show mixed or minimal effects.

However, experts caution that supplements aren’t a miracle solution, quality varies, and evidence remains limited. Always consult a specialist before trying supplements, as some may interact with medications or cause harm at high doses.

Big-Picture Threats and Prevention

Even with personal lifestyle changes, environmental factors play a major role. Global air pollution, pesticides, plastics, and other endocrine-disrupting chemicals are linked to long-term declines in sperm counts. While an individual cannot control these entirely, reducing exposure (avoiding unnecessary plastics, limiting contact with heat or chemicals, choosing organic or well-washed produce) and advocating for public health measures are practical steps. Recent global reviews have highlighted these environmental threats to male fertility.

How To Reverse Male Infertility?

Male infertility is not always permanent. Many causes, such as obstructions, varicoceles, hormonal imbalances, or infections—can be treated or reversed. Lifestyle changes and certain medical or surgical interventions can improve outcomes for many men.

Conversely, genetic factors, severe testicular damage, and gonadotoxic injuries are usually irreversible, requiring assisted reproductive techniques or other family-building options. A structured diagnostic assessment and an individualized treatment plan—including genetic counseling when needed are essential.