Why does my home have mold and musty odors?
The key to controlling mold is to eliminate its source of moisture. This moisture can come from:
· leaks in the roof or around doors and windows
· plumbing leaks and sewer backups
· condensation on the inside of cold surfaces, especially basement walls and floor (which are cool year-round) and exterior walls and windows during the winter.
· leaky basements, especially during wet weather
· showering or bathing without a bathroom fan, cooking without a kitchen fan, or having a clothes dryer with the exhaust blocked or not connected to the outside.
Mold grows on organic material such as paper, cardboard, fabric, particle board, or sheetrock paper. Clean or replace these materials if they have supported mold growth and avoid storing this type of material in areas with moisture problems unless they are enclosed in plastic containers or bags. Don’t use carpeting on basement or slab-on-grade floors.
To minimize condensation, make sure the dryer exhaust is directed outside and is not blocked, use the bathroom fan when bathing or showering (and for 10 minutes after), and use the kitchen fan, especially if you have a gas stove.
What relative humidity levels should I maintain in my home?
To eliminate condensation and control mold growth, maintain relative humidity in an unfinished basement space below 60%. Especially during the summer, this will only be possible if there is a door separating the basement from the first floor, and all doors and windows into the basement are closed.
Desirable relative humidity levels in finished basements and upper floors depend on the season of year and the type of construction. In winter, if condensation is present on ceilings, walls, or doors, or if condensation on windows causes visible mold growth, try to increase air circulation to the area by doing things like moving furniture away from walls or by opening window blinds slightly. Condensation (except in basements, where the walls are kept cool by contact with the earth) will not occur indoors during warmer weather unless there is a strong moisture source, like long hot showers or a plugged dryer vent. Apart from these sources, visible mold on upper floors during warm weather will usually be due to a leak or a spill.
How can I control dust mites in my home?
· Wash bedding frequently in hot water
· Change sheets frequently
· Regularly vacuum mattresses
· Use mattress and pillow covers
Remove rugs and replace carpeting with smooth-surfaced flooring
· Vacuum carpets, rugs, and upholstered furniture frequently using good IAQ vacuuming practices
· Reduce clutter (to eliminate places for dust to accumulate)
· Maintain relative humidity levels, especially in sleeping areas, below 60%
Using a higher efficiency furnace filter can help, and it should be considered if more extreme control is needed. But it is not a substitute for the source control strategies above and, for people with normal sensitivity, it has a minor effect. And, your furnace filter has to be matched to your furnace; consult the manufacturer’s recommendations.
Furnace duct cleaning is not necessarily a good use of your family’s resources. Read the EPA publication Should You Have the Air Ducts in Your Home Cleaned?
What are good IAQ vacuuming practices?
Use a vacuum with a HEPA filter. A whole house/central vacuum system is even better, since it exhausts to the outside. If these options aren’t available, open doors and windows while vacuuming and try to vacuum when no one with dust sensitivity is present.
What are good IAQ ventilation practices?
Homes with a high occupancy rate, especially tightly constructed homes built since the 1980s, often do not have enough natural ventilation to remove pollutants associated with indoor activity. If your home has a distinct smell, or if visitors to your home comment that it seems stuffy, consider increasing natural ventilation by opening a window one inch for each occupant in the room. A consultant (including Linn County Public Health) can measure carbon dioxide levels in your home – high CO2 levels are an indicator of a low air exchange rate. A heat recovery (or energy recovery) ventilation unit can be added to your HVAC system to bring in fresh air without losing heat (or gaining it in the summer.)
What are unhealthy sources of make up air?
When air is exhausted from your house by ventilation fans, furnace combustion, or from the stack effect, a vacuum is created and air has to enter the house to make up the deficit. Unhealthy sources of makeup air include soil gas from unsealed basement sump pits or from cracks and seams in the basement walls and floor. These gases commonly include carbon dioxide, radon, and elevated moisture. This suction can also pull gas from natural gas water heaters, furnaces, fireplaces back into the house.
What about fragrances?
This subject is controversial, and the volumes of material on the web contain little definitive research. However, Linn County Public Health does not recommend use of indoor air “freshener” fragrances, especially when someone with special sensitivity such as asthma is present.
How can I test and lower my family’s risk to radon gas?
Radon self test kits are low cost and readily available through hardware stores and many public health agencies. Common radon mitigation systems will reduce exposure to radon as well as other soil gases which commonly enter homes from the soil surrounding the basement.