IAQ Concerns for Hospitals

Feb 2, 2022

Hospitals are places where people go to get healed. Unfortunately, ~ 1 in 31 hospital patients gets a healthcare-acquired infection. Just as a doctor starts with an overall check-up of the patient, an indoor air quality (IAQ) assessment provides a baseline to evaluate a building’s performance. Improving IAQ starts with measurement. In this blog, we discuss common IAQ concerns found in a hospital setting.

Microbial IAQ Concerns

Because hospitals generally try to maintain relative humidity between 30 – 60%, they typically humidify the air. But humidification systems bring risks of microorganisms such as bacteria and mold. One risk is related to the water quality. Treatment chemicals or bacteria in the water could pose an indoor air quality problem once aerosolized. Another risk relates to humidity that condenses out of the air. Condensation may form within the air handling unit and/or downstream (ductwork, supply diffusers, windows, etc.) and can result in mold growth.

Hospitals often have variable occupancy with some rooms being vacant for long periods of time. Intermittent room use can result in undetected mold growth and stagnant water in pipes. One severe risk factor with stagnant water in pipes is the amplification of Legionella bacteria. When hot water pipes are used after a long time of no use, immunocompromised patients may breathe in Legionella bacteria and contract Legionnaires’ Disease. For this reason, robust water maintenance programs are so essential to maintain healthy hospitals.

Asbestos IAQ Concerns

In many buildings built before the late 1970s, there is the possibility of asbestos containing materials being present. These materials may be present in the HVAC related systems such as ductwork insulation, furnace insulation, and pipe insulation. Asbestos can also be present in materials such as fireproofing, flooring and wall systems. Asbestos-containing materials left in good condition pose minimal risk if left undisturbed according to the EPA. The employees who work with these materials are at higher risk of exposure such as maintenance workers and HVAC professionals. These materials are often managed by an operations and maintenance (O&M) plan however, a these plans are typically only as good as the governance ensuring they are followed.

VOC IAQ Concerns

Another Hospital IAQ concern is VOCs. The copious use of hand sanitizers resulting in elevated concentrations of VOCs such as isopropanol and ethanol. Sterilizing equipment may lead to elevated levels of harsh chemicals such as glutaraldehyde and phenol in hospital air. Rigorous cleaning programs also lead to cleaning chemicals used on a regular basis throughout the hospital. If the hospital is not properly ventilated, these VOCs can reach concerning levels.

HVAC IAQ Concerns

Local exhaust fans and hoods can make managing air pressure in hospitals difficult. Negative air pressure can bring in outdoor pollutants (mold spores, pollen), humidity, or cold temperatures in the winter. Mismanagement of air pressure can also cause problems in hospitals where the most vulnerable (infants, organ transplants, etc.) must be under the same roof with those that are most infectious (COVID, C.diff, etc.).


While many of these concerns seem alarming, especially in a medical setting, there are controls in place to prevent these contaminants from reaching patients. The first is engineering controls monitoring systems such as HVAC. The other are operations controls which include operations and maintenance programs. If you are concerned about the air quality in your hospital please reach out to an IAQ and/or industrial hygiene consultant such as Indoor Science.