The prevention and treatment of indoor air pollution in our homes is essential to protect our health. To manage air quality in the home, you also need to monitor humidity levels. In fact, breathing air that is too humid or too dry can have harmful effects on our respiratory system.?Humidity levels in the home can vary greatly between countries, continents and climatic zones. The optimum level of humidity in the air is considered to be between 50% and 60%. Simple solutions exist to achieve this optimum level of humidity and so to preserve our comfort and health.