5 min readNew DelhiUpdated: Jul 6, 2026 03:07 PM IST
While some exposures to environmental toxins are backed by decades of scientific evidence, others continue to spark debate, making it difficult for people to distinguish genuine health risks from exaggerated fears. To help simplify the conversation, Dr Jeremy London, a board-certified cardiothoracic surgeon, recently ranked several common environmental exposures by their potential impact on health.
Among the highest-risk exposures on his list was secondhand smoke, which he rated 9 out of 10. “Secondhand smoke. This is a real one. I would give it a nine. You know, this is a true carcinogen for never-smokers who are exposed to secondhand smoke. They have a 20 to 30 per cent increased risk of lung cancer.” On the other hand, he gave mobile phone electromagnetic fields (EMF) a much lower rating. “This is a scary one, and we hear about it a lot, but with normal usage, the data really doesn’t show that it’s a significant risk. I’d have to give this one a two (sic).”
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
Dr London also pointed out that not all mould poses the same level of danger. “Well, this one depends. A standard regular mould really causes mild symptoms. I would give that one a three. Black mould can cause some serious illnesses. I would give that one a seven (sic).” When it comes to medical imaging, he stressed that the risk from X-rays depends on the cumulative dose rather than a single scan. “Radiation is a known carcinogen, but it’s dose-dependent. One to two X-rays, normal kind of follow-up X-rays — nothing to worry about. But 20 X-rays, some of which you maybe didn’t need, that’s a different conversation. And I’d really have to know the dose before I laid a number on it.”
One area where Dr London believes the science is still evolving is microplastics. “Microplastics. You know, the data has shown that microplastics are found in blood, lungs, and even the placenta. They’re really everywhere, and they’re very difficult to eliminate, but I think it makes sense to try to reduce your exposure to microplastics. The data is preliminary. Ask me in five years.”
But which environmental exposures truly deserve our attention, and which ones may be causing unnecessary anxiety? We asked an expert.
Which environmental exposures pose the greatest health risks?
Dr Rahul Mehrotra, Chief, NIC & Clinical Cardiology, Artemis Hospitals, tells indianexpress.com, “Secondhand smoke is the strongest proven health risk of these exposures. It has thousands of toxic chemicals which increase the risk of lung cancer, heart disease, stroke, asthma and respiratory infections even in non-smokers. Mould in the home can cause allergies, asthma and breathing problems, especially in sensitive people, and this can also affect health.
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He adds that medical radiation is safe, but there is a small risk, and it should only be used when necessary. The evidence linking cell phone EMF and microplastics to major health problems is limited, so they remain low-priority concerns compared with well-established environmental risks today.
Practical ways to reduce environmental toxin exposure
Dr Mehrotra suggests that the best way is to stick with cheap, simple habits that are good for you, rather than trying to eliminate every possible source of exposure. Avoid smoking and secondhand smoke. Keep your home dry to prevent mould. Drink safe water. Wash fruits and vegetables. Have good indoor ventilation.
“Follow medical advice before imaging tests with radiation. Glass and stainless steel containers for hot foods can also help with excess plastic exposure. Small steady changes are better than drastic measures. Resilience is also about taking care of yourself, eating well also exercising regularly and getting enough sleep,” states Dr Mehrotra.
How to interpret studies on environmental toxins
Click each point to understand how to separate established evidence from emerging research:
🧪 One study is not the final answer
Initial studies may identify potential risks, but they do not necessarily prove that an exposure directly causes illness in people.
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📚 Look for consistent evidence
Medical advice is based on multiple well-designed studies that repeatedly produce similar findings over time, rather than on a single report.
🌍 What about microplastics?
Researchers are still studying the long-term health effects of microplastics and other newer environmental exposures, so the evidence continues to evolve.
✅ Key takeaway
Rather than reacting to sensational headlines, rely on trusted public health advice, follow credible sources and avoid making major lifestyle changes based on limited or early evidence.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.