World News for Students of English

16-07-2026 07:00

A four-year study tracking over 1,200 men in Utah has revealed that breathing in common air pollutants like ozone and nitrogen dioxide can negatively affect their reproductive health.

The research shows that exposure to these man-made contaminants during sperm development is linked to subtle DNA changes. Specifically, it affects a process called methylation, which acts like a switch turning genes on and off. Experts warn that these changes can lead to decreased sperm counts and lower motility, which is the sperm’s ability to swim. Because these pollutants come from heavy industrial activity and busy city traffic fumes, men living in larger, highly polluted cities face a greater risk of fertility issues.

These genetic changes inside the testes can have long-term consequences not only for the individual’s fertility but also for their future children. To protect themselves, people are advised to reduce unnecessary exposure by wearing face masks during heavy smog or taking occasional trips out of the city.

Difficult words: exposure (a situation where you are not protected from something dangerous or dirty, allowing it to affect your body), contaminant (a substance that makes something like air, water, or food dirty, unsafe, or impure), consequence (a result or effect of an action or situation, which is often bad or unpleasant).

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