What effect does increased humidity in mine air have on workers?

Increased humidity in mine air has a notable impact on workers, primarily decreasing comfort and safety. High humidity levels can lead to discomfort as the body struggles to regulate temperature through the natural process of sweating. When sweat does not evaporate effectively due to high moisture content in the air, it can cause workers to become overheated, leading to heat stress and fatigue.

Additionally, high humidity can create a conducive environment for the growth of mold and bacteria, posing health risks to workers. Poor air quality can further exacerbate safety concerns, as the overall conditions may impair concentration and physical performance, increasing the likelihood of accidents in an already hazardous environment.

The other options do not accurately represent the effects of increased humidity. Increased productivity is unlikely in uncomfortable conditions, and while some may argue that humidity has no significant impact or even improves air quality, the evidence clearly indicates that elevated humidity presents more risks than benefits in the context of mine ventilation and safety.