IAQ in Buildings: Keeping Occupants Healthy

Heating Ventilation and Air-conditioning (HVAC) Systems are the nerves of any business offices, commercial building, hotels, hospitals and even our homes are supported by any type of HVAC and inside air in these premises is termed as Indoor Air. Occupied buildings require a supply of outside air to maintain inside carbon dioxide. Thus, the quality of outside air affects the quality of inside air.
Indoor Air Quality (IAQ) also depends on various other factors like VOCs, level most of our day is spent across the office, home, shopping or restaurants. So, the quality of indoor air plays a unique space in our life. The quality of indoor air affects health, provides comfort or discomfort to us.

Factors Affecting Indoor Air
• Quality of Outdoor Air
• Quality of Air Handling Units
• AHU rooms used as storage
• Chemicals like carpet cleaning, cleaning agents, paint &
varnishes, room fresheners
• Scheduled maintenance and upkeep of ducts (Passages or
conduits used to supply & return)
• Occupancy per SQFT (increased CO2).

Health Effects of Poor IAQ

Uncleaned, bad or polluted air has both short-term and long-term effects. Short-terms effects include dizziness, headache, irritation in eyes; which, if continued for long lead to asthma, lung problems, neurological disorders and other severe health issues.

HVAC & IAQ

• Outdoor Air Quality: To improve IAQ, the source needs to be controlled, HVAC installation cannot do much to the outside air quality, except advising society, agencies, government and general public arranging case studies and awareness campaigns.
Now-a-days, big air-purifiers installation is started in areas like Delhi or NCR. Its overall effectiveness is still under study.
• Quality of Air Handling Units: In occupied buildings, outdoor air enters as fresh air to AHUs and post being cooled or heated, this is supplied to conditioned space i.e. work spaces, occupant areas via ducts. During interaction of outside air with cooled space, ventilation rate procedure, mixing of fresh air quantity should be controlled by placing automation to fresh air dampers. Possibly fresh air should be passed through some TFA units.