By Michael Tobias
The adverse effects of inferior air quality in our homes and other buildings can be alarming, ranging from relatively mild irritations of the nose, throat, and eyes, to headaches, tiredness, and dizziness, severe respiratory diseases and even heart disease and cancer.
Indoor environmental quality (IEQ) has become a major concern in our homes, schools, and workplaces because it not only tends to lead to poor health but is also linked to productivity problems and learning difficulties.
IAQ is more than just air quality, incorporating a broader spectrum of indoor conditions that also include lighting and thermal comfort, access to sunlight during the day, to views, and pleasant acoustics.
But air quality is a major concern. Research undertaken by the American College of Allergies indicates that about half of all illness is either caused or aggravated by indoor air that is contaminated or polluted in some way. Of course, the level of contamination, as well as type, does make a difference, but indoor pollution comes from so many different sources, from dust and cigarette smoke to bacterial buildups in pipes and ducts, and it’s virtually impossible for any of us to avoid it – certainly without help from science and technology.
Before we consider how to improve air quality at home or in the office, it’s a good idea to identify the sources and typical causes of indoor pollution.
Common Causes of Polluted Indoor Air
Being aware of what is polluting the air makes it easier to solve the problem.
While inferior indoor air quality in our homes and office buildings is commonly a result of particles or gases that have been released into the air, including a variety of volatile organic compounds (VOCs) that are released from various materials and products, the most common reason pollutants build up in the air is because of inadequate ventilation. It stands to reason that if there isn’t an effective ventilation system that removes air pollutants from inside the building, and there isn’t a way to dilute indoor pollution with fresh air from the outside, the stale contaminated air will just stay inside and we will inadvertently keep breathing it in.
Another cause of pollution increasing indoors is because the filtration of the air is inefficient. It may be that the heating, ventilation, and air-conditioning (HVAC) system is inadequate, or it may have been installed incorrectly or without the right procedures in place.
The United States Environmental Protection Agency (EPA) raises concern about these pollutants:
- Various byproducts of combustion (for heating or cooking) including particulate matter and carbon monoxide as well as tobacco smoke.
- Substances that originate from natural sources including mold, the radioactive gas radon that occurs naturally in the atmosphere, and microscopic pet dander shed by cats, dogs, birds, and other creatures.
- Biological agents including some types of mold.
- Residue from toxic pesticides, lead, and asbestos, all of which are hazardous. Lead, which is now banned worldwide, is a toxin that affects the nervous system, but it was commonly used as an ingredient of paint until 1940. Also a banned material, asbestos was commonly used as part of ceiling, wall-siding, building insulation, and roof tile materials until the late 1970s. Generally, it isn’t hazardous unless it deteriorates or is broken and finds its way into the atmosphere.
- VOCs, many of which are found in insecticides, paints, and cleaning supplies.
- Ozone, that is sold as an air cleaner but which might be toxic, especially when used in our homes and offices. Note that there are no ozone generators approved by the U.S. federal government for use in occupied indoor spaces. When inhaled, ozone can damage the lungs, aggravate asthma, and lead to chest pains, throat irritations and coughs, and shortness of breath.
How to Deal With Polluted Indoor Air
When those in your home or office show symptoms that are associated with indoor air pollution, it’s wise to investigate the possible causes. If feasible, contact a company that offers HVAC engineering services in Chicago, New York, Atlanta, Los Angeles, or the city or town where you live and ask for an air quality audit that will identify air quality issues and suggest ways of improving them.
In the U.S., the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has guidelines for minimum air quality that designers use. There are two procedures they recommend to determine the minimum acceptable ventilation rates:
- The Ventilation Rate Procedure that bases its rate on space functions within different types of buildings. Commonly used in commercial and industrial buildings, it is based on varying respiration rates that result from activities undertaken by occupants.
- The Indoor Air Quality Procedure involves monitoring specific air contaminants.
Even if these procedures aren’t undertaken, experienced HVAC engineers will know which strategies will work best in your indoor environment.
Strategies to Improve Indoor Air Quality in Your Home or Office Building
The EPA recommends three basic strategies:
- Source control that involves eliminating the source of air pollution or reducing its emissions. So, for instance, if there are materials in the house that contain asbestos, rather than removing them (which in itself can cause contamination if the material breaks up), it may be possible to seal the area. Source control is considered to be the most effective solution for homes.
- Improved ventilation that effectively brings more fresh outdoor air into the home or office. Presuming there is a ventilation system in place, opening doors and windows, operating attic or window fans, or running window air-conditioners while the vent control is open will increase the ventilation rate from outside. If there are kitchen and bathroom fans that exhaust outdoors, these will remove air pollutants from these rooms and also increase the ventilation rate.
There are also advanced mechanical systems that are designed to bring outdoor air inside via the HVAC system. Some utilize air-to-air heat exchangers which are highly energy-efficient. An HVAC engineer will advise.
- Air cleaners that are designed to collect and remove pollutants from the air inside range in efficacy and price. They generally remove particles though and not gaseous pollutants.
While air cleaners can be effective, the EPA does not recommend using them to try and reduce radon levels because they only partially remove radon decay products and don’t stop radon from entering the indoor environment.
In addition to the factors relating to the quality of indoor air discussed above, the air exchange rate, occupant behavior, outdoor climate, and weather conditions also play a role. So these should also be taken into effect. For instance, some climatic conditions encourage the growth of mold if there isn’t adequate ventilation, and the air exchange rate can easily be affected by cracks and open joints that aren’t meant to be in a building.
Ultimately, no monitoring network measures air quality routinely in homes, schools, and offices in the U.S. or, for that matter, most other countries. So there is no reliable data other than that published in scientific literature and government publications. But you don’t need data to tell you there’s something wrong with the air quality in your home! If you suspect the air quality is compromised, do something about it.