Indoor Air Quality in Schools

Beyond COVID-19, reducing the spread of indoor pollutants is important to preventing the spread of illnesses. In an active setting like a classroom, illnesses can be passed easily between students and teachers. By investing in the Indoor Air Quality (IAQ) of your school, you are not only protecting your occupants from potentially harmful diseases, but you are also improving the cognitive performance of students.

Watch the video from The University of California-Davis to better understand the importance of proper ventilation in schools.

Dilution (or ventilation) is the most common method of indoor air quality treatment. Generally speaking, buildings contain a number of contaminants ranging from VOCs from construction materials, to smells, to off gases from human occupants, to process gasses from varying procedures done in buildings. As the concentration of those contaminants increase, the mechanical system blends a pre-determined amount of recirculated air (to keep heating/cooling costs at a minimum), with fresh air from outside, and relief/exhaust the remaining air to keep a balanced building. When the newly introduced fresh air blends with the recirculated air, it dilutes/lowers the concentrations to an acceptable level. When outdoor temperatures are hot in the summer or cold in the winter, limitations are placed on the amount of fresh air that can be brought into the system to prevent damage to the equipment and/or high utility costs to condition the air. It’s more than just pulling and pushing air – it’s a mechanical balance that pushes fresh air through to your occupants while reducing contaminants.

You know what filters do, but are they configured correctly for your building to maintain higher indoor air quality for your occupants? Filtration is also an extremely common method to improve indoor air quality and is nearly always used in conjunction with dilution. As air is circulated through the mechanical equipment, a filter is used to catch and remove airborne particulates ranging from pollen, to spores, to dust, and even viruses. Not only does this remove particulates from the air to keep the air fresh for people, but it also helps improve the mechanical equipment efficiency when its components are kept clean. However, putting too fine of a filter (too high of a MERV rated filter) on a piece of equipment can constrict its performance and lead to potential equipment damage. Filters should always be changed on a regular basis and used in conjunction with other approaches to treat items that it does not remove, such as VOCs or smells.

UV lights can be placed in equipment, placed in ductwork, or brought in as stand-alone portable devices to shine intense UV rays on all particles flowing through your mechanical system. The UV rays will kill viruses, bacteria, spores, mold, and breakdown some VOCs; very similar to how the sun does so outside. The technology has been used in hospitals, laboratories, and other indoor building applications for decades to show a long-standing track record of success. UV lights are not just for hospital use anymore; they are the next level of improving Indoor Air Quality in your buildings.

Ionization renders virus/bacteria innate, allowing for better filtration at a low-cost. Ionization units (BPI or NPBI) have been the newest center of attention when it comes to IAQ. Ionization as a technology has also been around from decades and is simply the process of creating an electrical field strong enough to generate ions. Some ionization units generate electrical fields that are strong enough to split oxygen, creating ozone, which can be harmful to humans. However, most ionizers now are UL2998 approved not to create ozone because their electrical fields are low intensity. The ions generated from the electrical field will attract and stick to particulates in the air the same way that they do in nature. When attaching to viruses and bacteria they can “plug up the hooks” that the virus/bacteria would use to attach to a host; which renders them innate. They may also remove a hydroxide from them which can keep them from attaching to hosts. In all instances, if the ions attach to a particulate and cause that particulate to become charged, it will then cause the particulate to bond to another oppositely charged particulate; making the two of them together bigger in size and weight. This causes them to fall out of the air faster, or get stuck in the filters easier.