Question: what are the causes of poor indoor air quality?
Answer: Biological Agents. These agents include mold, pollen, bacteria, viruses, and animal dander. ... 
Cigarette Smoke. A large cause of indoor air pollutants is secondhand smoke. ... 
Combustion Agents. ... 
Radon Contamination. ... 
Formaldehyde & Asbestos. ... 
Increase Ventilation. ... 
Use An Ultraviolet Air Purifier. ... 
Reduce Indoor Humidity.