An Air Quality specialist checks the levels of Carbon Monoxide, Carbon Dioxide, relative humidity, and temperature in your house. The specialist would also have a moisture reading that can tell whether the walls of a house are water infiltrated. A short term radon test gets inserted in the lowest level of the house that people live in for 5 days to check for elevated levels of radon.
Carbon Monoxide usually is present in houses that have gas leaks from stoves, leaks in water boilers, or from some furnaces. Long term exposure to carbon monoxide can have serious side effects. The American Conference of Governmental Industrial Hygenists made a threshold of 25ppm for an 8-hour work day [ACGIH 1994, p. 15]. Since people live in their houses and spend more than 8 hours in their home, the threshold is closer to 10ppm in homes.No standards for CO have been agreed upon for indoor air. The U.S. National Ambient Air Quality Standards for outdoor air are 9 ppm (40,000 micrograms per meter cubed) for 8 hours, and 35 ppm for 1 hour (epa.gov). Carbon Monoxide is an asphyxiant that prevent blood from carrying sufficient oxygen. This can give symptoms such as headaches, dizziness, confusion, fatigue, and lack of muscle coordination.
Radon is a naturally occurring radioactive gas that comes from the soil. Soil being the source, basements are most susceptible to higher exposures to radon because its closest to the ground. The gas can come up an unsealed sump pit, right into the basement and accumulate rapidly. EPA made a national standard of 4piC/L (E-2121-03 2003) for radon because having long-term exposure to elevated radon doubles the chance of lung cancer than someone not exposed. New and energy efficient tight houses tend to be most susceptible to high radon levels because they don't have proper ventilation or have no way to mitigate the radon from coming into their home.
Carbon Dioxide is a common gas and occurs everywhere in the air. However, in homes, carbon dioxide is directly related to the number of people in a room or home. Both people and pets breathe out carbon dioxide. Carbon dioxide is heavier than the rest of air, so it usually accumulates in low areas such as basements. Other sources in the home for carbon dioxide are space heaters, clothes dryers, fireplaces, stoves, or any other gas-burning appliances that are not vented to the outside. The health effects of exposure to high levels of carbon dioxide could be serious, but high levels rarely ever occur in residential houses. Increasing carbon dioxide decreases oxygen levels in your body. Common side effects of relatively low level long time exposure are headaches, increased heart rate, increased fatigue, and breathing problems (especially people with COPD). Carbon Dioxide is more of an indication of how well the ventilation is in the home. Recommended levels for adults are under 1000ppm and for children, under 600ppm. Under 1000ppm, odors won't stay in an area like a kitchen for very long.
Mold is a trigger for many people with asthma and allergies. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that have been wet for over 48 hours. If the relative humidity is above 60%, then spontaneous mold growth can occur on those wet or dam spots. There are many types of mold, and none of them will grow without water or moisture (EPA, 2008). Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis). Allergic reactions to mold are common. They can be immediate or delayed. Molds can also cause asthma attacks in people with asthma who are allergic to mold. In addition, mold exposure can irritate the eyes, skin, nose, throat, and lungs of both mold-allergic and non-allergic people (EPA, 2008).
Relative Humidity can easily be controlled and is very important towards controlling other indoor air quality issues. Relative humidity at 60% or above creates an environment where dust mites can thrive. Dust mites are a known allergen for many people and some people who can't control the dust mites in their homes buy allergen-free pillow cases and bed sheets. Also, if relative humidity reaches over 60%, then spontaneous mold growth can occur. Mold in the bathroom is because of relative humidity more than any other reason. One easy way to prevent bathrooms from getting mold in them are using the bathroom vents before, during, and after showers. A good way of controlling relative humidity for the rest of the home is to be aware how humid it is. Awareness would require a humidity temperature monitor. If you have one and notice that its getting above 50%, a dehumidifier could be turned on until the level is more desirable.
Temperature is very important towards people's comfort. Because of people's comfort, houses have devices that can control the temperature. Many people have furnaces or water boilers to heat the home. To keep the home cool in the summer, people use air conditioning. What's great about air conditioning for indoor air quality is that it uses a combination of air from the inside and the outdoors. This process allows for some fresh air to enter the house and keep the levels of Carbon Dioxide and Radon down by ventilating the home.
If a house is not well insulated, the outside temperature can be a big deal. If the outdoor temperature is below freezing, the walls of the house could very well be below freezing. This means that when the indoor wall comes in contacts with the indoor temperature, the wall will reach a high relative humidity and show presence of condensation. When that process occurs its called "sweating walls". Remember, if the walls "sweat" for over 48 hours, mold can start growing on the wall. This is why insulation is so important for houses in colder climates.
Sump Pits have been found to affect the air quality. Because they give a passage way to the outdoors through the soil, radon can accumulate in the pit and leak out into the home. Also, very high levels of Carbon Dioxide have been found coming out of an open sump pit. Sump pits can be very useful for people's home that are below a water table, but for protecting the indoor air quality, they should remain sealed properly. A sealed lid means that there are no open holes or cracks between the cement floor and the circumfrence of the lid.
Indoor Air Quality Frequently Asked Questions
Find out some indoor air quality results from the children's home asthma management program.
For additional information about indoor air quality call Linn County Public Health @ (319) 892-6000.