What is normal indoor air quality levels?

Normal indoor air quality levels are determined by the concentration of pollutants in the air. The most common pollutants are carbon dioxide, carbon monoxide, dust, pollen, mold, and volatile organic compounds (VOCs). The acceptable levels of these pollutants vary depending on the type of building and the purpose of the space. Generally, the acceptable levels of carbon dioxide should be below 800 ppm, carbon monoxide should be below 9 ppm, dust should be below 50 μg/m3, pollen should be below 10 μg/m3, mold should be below 500 CFU/m3, and VOCs should be below 0.5 mg/m3. It is important to regularly monitor indoor air quality levels to ensure that they remain within acceptable limits.