Indoor Air Quality Solutions, IAQS

By The Home Ventilating Institute (HVI)

There are four basic strategies for improving air quality. First, it is important to always practice source control and separation; then a proper mechanical ventilation system should be used to reduce the pollutants. Finally, filtration can clean up remaining pollutants, that is, polish the air.

Strategy 1: Source control is simply eliminating the source of a pollutant. For instance, if you use cleaning products low in volatile organic compounds (VOCs), you won’t add those pollutants to the indoor air every time you clean the house.

Strategy 2: Practicing separation means creating a barrier between the occupied part of the house and the pollution source. If a pollutant can’t reach you, it can’t harm you. So, an airtight house can be a good way to separate pollutants such as those coming from insulation from the occupants.

Strategy 3: Ventilation is more than just air circulation between rooms—although that is a part of its purpose. With ventilation, there must be an exchange of air between the indoors and the outdoors. The best and most efficient way to exchange the air in a house is to rely on a mechanical ventilation system, which can be controlled, rather than relying on natural or accidental air pressure changes which may not occur as frequently as desired or in the areas of the house where the air changes are most needed, such as the bathroom or kitchen.

Strategy 4: Filtration is often combined with ventilation to maintain good indoor air quality. Filters capture airborne pollutants but they do not bring in fresh air, remove excess humidity, nor create oxygen; therefore, they should not be relied on as a substitute for a mechanical ventilation system

Two types of controlled ventilation systems

A high-volume local ventilation system is good for dealing with the occasional peak pollution levels or excess moisture in specific rooms. Local ventilation is desirable in bathrooms, kitchens, and other service rooms that regularly have high levels of moisture or pollution. Sometimes local ventilation is called spot ventilation because it ventilates one spot in a house.

General ventilation is referred to as whole-house ventilation because it is for every room in the house. Some people call general ventilation primary or basic ventilation because its purpose is to provide the air that occupants need on a continual basis. After all, human health is a primary consideration. A whole-house ventilation system is a relatively new term for a mechanical system that moves air through a house continuously at a relatively low flow rate. The purpose of a whole-house ventilation system is to provide a continuous air change for fresh air to maintain healthy conditions for the occupants and the building itself, not to cool the temperature of the living space. So the purpose of a whole-house ventilation system is very different from the purpose of a whole-house fan or whole-house comfort ventilator.

Consult with your builder or ventilation contractor to ensure that your house has proper mechanical ventilation. Ensure the quality of your indoor air by using ventilation products certified by the Home Ventilating Institute.

Adapted from: Understanding Ventilation: How to design, select, and install residential ventilation systems by John Bower © 2010 The Home Ventilating Institute

Water is the key. Without it, mold growth cannot start, much less multiply and spread. The easiest way to prevent the mold from gaining a foothold is to control dampness. Keep your home clean and dry. When water stands for even 24 hours, common molds can take hold. Keeping humidity levels below 60% and venting moisture from showering and cooking to the outside are several ways to prevent the conditions that can lead to mold growth. Other ways include:

•Clean and dry up spills within 24 hours
•Dry out wet building materials and carpets within 24 hours
•Use an air conditioner or a dehumidifier to reduce the indoor humidity levels below 60%. If you have a central air conditioning system and need a dehumidifier to reduce relative humidity below 60%, you should have the air conditioning system examined for problems
•Do not carpet bathrooms or basements

Note: While most experts suggest a relative humidity of less than 60%, below 50% is best for controlling both mold growth and dust mites. Dust mites are microscopic animals related to spiders, ticks and other mites. Dust mites eat mold and dead human or animal skin scales (flakes) and leave allergenic proteins. Dust mites reduce allergen production at these lower humidity levels.

Teachers have a significant role maintaining good air quality in classrooms. Below are a few tips for teachers that if followed can assist in maintaining or improving the air quality of classrooms.

Tip #10 – BLOCKING HVAC SUPPLY OR RETURN AIR DUCTS REDUCES AIR QUALITY

Classroom air supply systems are critical to the classroom environment. It is important that air systems are not manually turned on or off and are not blocked. Classroom air systems will not work properly when the system is even partially blocked. If there are issues with your air supply system, ask the front office to enter a work request for Building Services to address the issue on your behalf. If you are storing materials like the ones shown below finding alternate storage space will allow the system to better perform.

Tip #9 – MINIMIZE UPHOLSTERED FURNITURE AND STUFFED TOYS

Cloth furniture, stuffed animals, pillows and other such articles are reservoirs for allergens and asthma triggers. It is important to wash these types of materials out of the classroom or cleaned regularly to keep allergens to a minimum.

Tip #8 – PREVENT DUST ACCUMULATIONS

Dust can be a serious problem for asthmatics or others with upper respiratory sensitivity. Keeping clutter to a minimum will allow your custodian to take better care of your room. For instance, keeping stored materials in plastic boxes with lids allows them to be dusted. Your custodian takes good care of your room. However, the hygiene of personal items, media carts, computers and stored materials is the responsibility of the teacher(s) using or storing these items.

Tip #7 – ANIMAL DANDER IS AN ALLERGEN

Furry animals produce dander which can be both an allergen and asthma trigger. It is best not to have furry animals in the classroom. If animals are required for curriculum the cages should be cleaned on a daily basis and more sensitive children should sit on the opposite side of the room from the animals. Animal food should be stored in sealable vessels. You should never be able to smell the presence of the animals in your classroom.

Tip #6 – MASKING AGENTS PUT CHEMICALS IN THE AIR

Masking agents introduce substances into the air that may smell nice to some, but may be offensive or upper respiratory irritants to others. It is best not to use masking agents in classrooms. If there is a building related problem causing odors, the masking agent makes it harder to find the problem. There have been a number of response actions conducted by district personnel where simply removing the masking agents out of the building resolved staff and student upper respiratory irritation.

Tip #5 – USE THE WORK ORDER SYSTEM TO ADJUST HVAC SYSTEMS

It is important that classroom air systems are allowed to run as designed. Tampering with the air system not only impacts your room, but may start a domino effect that impacts other classrooms too. If your classroom is not within the accepted temperature range contact the front office to request support.

Tip #4 – USE BREAK ROOMS AND OR CAFETERIA TO PREPARE FOOD AND BEVERAGES

Do not store or prepare food in classrooms unless there is a specific medical or curriculum need to do so. Food spoils, attracts pests and should be prepared in appropriate spaces. Home appliances are not intended for use in school buildings and generally do not have the appropriate ASTM rating.

Tip #3 – PERFUME AND COLOGNE ARE UPPER RESPIRATORY IRRITANTS TO SOME

Perfumes, aftershave and colognes may be serious upper respiratory irritants. Reduce use to a minimum while at school to avoid triggering asthma attacks or causing upper respiratory system irritation.

Tip #2 – REPORT WATER EVENTS PROMPTLY

Report floods, water leaks, or water spots to the front office promptly. By reporting these issues early the initial problem can be addressed by Building Services before the moisture becomes a more serious event.

Tip #1 – EDUCATE YOURSELF WITH FREE MATERIALS DESIGNED FOR YOUR BENEFIT

Empower yourself to improve the indoor environment by reading up on IAQ at the USEPA Tools for Schools IAQ Website.