Which of the following is a sign of poor indoor air quality?

Visible mold growth is indeed a significant indicator of poor indoor air quality. Mold thrives in damp environments and can proliferate in areas with moisture, such as around leaks or in areas of high humidity. When mold is present indoors, it can release allergens and irritants into the air, leading to respiratory issues, allergic reactions, and other health concerns for occupants.

In contrast, consistently clean air filters suggest that the ventilation system is functioning properly and effectively removing dust and particulates from the air, which indicates better air quality. Open windows with clear skies typically allow fresh air to enter the indoor environment, promoting better air circulation and quality. Low humidity readings generally signify a dry environment that can also be beneficial, as high humidity can lead to mold growth and other indoor air quality problems.

Recognizing visible mold growth as a sign of poor indoor air quality is crucial for maintaining a healthy living or working environment and addressing any underlying moisture issues promptly.