HVAC system
- dust or dirt in ductwork or other components
- microbiological growth in drip pans, humidifiers, ductwork, coils
- improper use of biocides, sealants, and/ or cleaning chemicals
Non-HVAC equipment
- emissions from office equipment (volatile organic compounds, ozone);
- supplies (solvents, toners, ammonia);
- emissions from shops, labs, cleaning processes.