5 Steps to Ensure Safe Indoor Air Quality (IAQ) in Multifamily Housing
Indoor Air Quality (IAQ) has long been recognized as one of the most important elements in any building, and especially in our homes where we spend the majority of our time. Despite this, most multifamily buildings today do not actively monitor IAQ, and the spotlight on IAQ is getting more intense as residents are spending more time in their residences as a result of COVID-19.
While most people are aware that the severe impact of pollutants can cause illnesses such as Sick Building Syndrome, what’s lesser known are the effects poor air quality can have on everyday decision making, productivity, well-being and the overall health of occupants. Property owners and managers need to consider not only the issue of extreme high or low humidity and its contribution to unhealthy conditions, but also how inadequate ventilation and filtration might inadvertently be creating less than optimal environments for occupants.
What determines the quality of indoor air? Buildings are home to many sources of air contamination, including volatile organic compounds (from cleaning agents, furniture and other materials), mold, bacteria, and viruses which we are especially concerned about now. Air quality can also be compromised by particulate matter including things like wildfire smoke infiltrating from outside, and also indoor sources such as cooking fumes. Finally, the CO2 that we breathe can cause poor air quality at higher concentrations. There are five key steps all multifamily owners and property managers should take to ensure that IAQ is safe for residents:
Step 1: Monitor and measure indoor pollutants. Today, inexpensive, cloud-connected sensors allow continuous monitoring of many of these pollutants. Information gathered from sensors can be used to ensure IAQ and identify areas of concern.
Step 2: Ensure appropriate ventilation as part of the HVAC systems (the “V” in “HVAC”), while avoiding bringing in outdoor pollutants. Older buildings can be problematic. They may be very “leaky” as a result of tiny but numerous gaps created during construction or through gaps that have developed over time. This results in haphazard ventilation that allows outdoor pollutants to enter and allows pollutants and odors to move from one apartment to another. These buildings also waste huge amounts of energy. Some 1970s buildings were built much more tightly to conserve energy, but without planned ventilation systems they created the conditions for poor IAQ by allowing pollutants to build up. Many mid-rise and high-rise buildings from this era allowed pollutants from a basement garage to flow up through the building into living spaces due to air pressure imbalances and the “stack effect.”
Step 3: Create a tight building envelope, coupled with an intentional ventilation strategy. Recent energy efficiency standards such as Passive House require leak sealing of exterior and interior walls, well designed mechanical ventilation, and a commissioning process that ensures balanced air pressure throughout the building.
Step 4: Filters are effective in removing many pollutants from the fresh air brought in by the ventilation system. Separate filters are used to remove indoor air pollutants from air that is cycling through the heating and cooling equipment. In an effort to improve filtration due to COVID, the American Society of Heating Refrigeration and Air-conditioning Engineers (ASHRAE) recommends upgrading filters to MERV-13 from the typical MERV-8 found in commercial HVAC systems. MERV-13 filters will remove a very high percentage of pollutants such as particulate matter, bacteria, droplets and a good percentage of viruses. Following this recommendation will improve all aspects of IAQ and contribute to a much healthier building. (MERV is an ASHRAE standard.)
Step 5: Inspect the HVAC systems professionally in a process called retro-commissioning, because faulty or misconfigured equipment can do more harm than good when it comes to keeping residents and staff protected from pollutants. Also the changes recommended for improving IAQ during COVID-19 may put additional stress on HVAC equipment.
For further information, start with ASHRAE’s COVID-19 recommendations for building operators