302 – Applications
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Indoor air quality problems can be found in any building whether it is residential or commercial in design. For the most part, all occupied spaces use heating/cooling systems to control the environment. Some spaces have more people per square foot than others, but overall they all share similar issues when it comes to Indoor Air Quality problems.
Indoor Residential Air Quality Problems
Most indoor air quality problems are associated with four areas: moisture, ventilation (or lack thereof), construction and filtration. The amount of moisture in a home is controlled by a couple of factors. One, the general humidity levels in the area and two, the amount of cooling (air conditioning) that is done in the home. If the home is located in a high humidity area of the country, then more air conditioning is needed to condense the water out of the air and provide cooler, dryer air. If cooling is inadequate or if the construction of the home is such that condensation forms on the walls, the probability of having mold grow in the home is greater. Where there is moisture (water) there is mold.
Ventilation is comprised of both airflow through the home via the heating/cooling system as well as the introduction of outside air. Construction techniques for today’s homes mean they are very, very tight, creating indoor air quality problems. In most cases they will have an air exchange rate of no more than .25 ACH (air changes per hour). The tighter the home the more the CO2 builds up and also more moisture is retained in the environment. The ability to introduce some fresh outside air and to exchange the air in the home at least 1.5 to 3 times per day is essential for proper ventilation and good air quality. Lack of proper ventilation leads to higher concentrations of airborne contaminants as well as increases in concentrations of gases from household chemicals and construction materials.
Lack of proper ventilation leads to higher concentrations of airborne contaminants as well as increases in concentrations of gases from household chemicals and construction materials.
Construction of the home consists of both the actual building materials, the tightness of the home and the heating/cooling system or mechanical system for proper environmental control. If the heating/cooling system is not properly balanced, it is very possible for the home to be under negative pressure anytime the HVAC fan is running. This significantly impacts the indoor air quality as it allows for the entry of fine particles and gases from the outside to be pulled into the occupied environment. If there is any communication between the attic or the outside and the living space, contaminants will be present if the negative pressure issue is not resolved. Many building materials can be a source of chemical out-gassing and with little ventilation and the negative pressure problems the indoor air quality is severely compromised. Again, mold and bacteria growth are more common in these situations.
The lack of good filtration and ventilation can also add to significant challenges in providing a healthy indoor environment. The air filters that come with any heating/cooling system are primarily just a very light duty fiberglass media or washable sponge type media. In either case, these air filters are designed to ONLY keep the blower/motor assembly clean, resulting in indoor air quality problems. They were never intended filter out small or respirable sized particles, gases or odors for the occupied space. These OEM air filters don’t remove any mold or bacteria or any of the fine airborne dust. These air filters are also not appropriate if you are going to introduce outside air through your return air duct.
Commercial Indoor Air Quality Problems
Commercial facilities can include office buildings, retail establishments, light manufacturing and assembly, restaurants, bars, etc. Like residential buildings, these facilities use heating/cooling systems with ductwork to provide for a conditioned space for the employees and patrons. Unlike residential buildings, they have a much higher density of people and equipment. Maintaining good indoor air quality is more challenging in these types of facilities.
The problems in commercial buildings are moisture, airborne particles, lack of proper ventilation, odors and gases from materials, etc. Due to the lack of fresh air ventilation and the inconsistency in humidity and temperature control, it is likely that more moisture will be present in these facilities and therefore more mold and bacteria problems will occur. In addition, these types of buildings use Air Handlers or heating/cooling systems that often employe only light duty or low efficiency air filters.
Many offices have numerous computers, printers, copiers and other types of office equipment that both generate heat as well as ozone in the case of some printers and copiers. These variables can significantly impact the quality of air in these types of buildings. Since the employees spend 8 hours per day (or more) in these buildings, they are subjected to a wide variety and high concentration of airborne contaminants all the time. Also, the lack of fresh air ventilation can increase the levels of CO2 in the building creating headaches and lethargy. In those buildings where smoking is allowed (bars, restaurants) the cigarette smoke adds a whole other level of airborne contaminant.
Institutional Indoor Air Quality Problems
These include schools, hospitals, day care centers, retirement homes, etc. The indoor air quality problems in these facilities are similar to those in the commercial buildings. One added problem in day care centers is the large numbers of younger individuals who tend to carry typical childhood diseases that are easily spread throughout the buildings and carried by the heating/cooling systems. Hospitals and retirement homes with lack of proper ventilation also are great breading grounds for communicable diseases that are easily spread throughout the facility. Institutional facilities can be the most challenging in terms of indoor air quality problems.