Indoor air quality (IAQ) is an important aspect of maintaining a healthy living and working environment. It's essential to test your indoor air quality regularly to ensure that your living and working space is safe and healthy. Here's what to know about indoor air quality testing.  Temperature and Humidity  High humidity levels can promote the growth of mold, mildew, and bacteria, which can cause respiratory problems. Mold and mildew can also cause damage to books, wood furniture, and walls.