Relief from sneezing and wheezing
Indoor air can be five times more polluted than the air outside. The culprits include smoke, mold, pollen, fungus spores, pet dander, dust mites (actually the feces of dust mites), and even allergen-bearing particles from disintegrated cockroaches! Various gases can also cause irritation and illness, including carbon monoxide, nitrogen oxide, nitrogen dioxide, and vehicle exhaust. Other pollutants are spewed out by furniture, building materials, and personal care products such as perfume, soaps, and deodorants.
If you or someone in your family is sensitive to whatever is wafting through the air in your house, first try to remove the sources of the pollution. If you've made that effort and are still suffering, it may be time to consider an air purifier.
- Do some detective work. If you can figure out which pollutant or pollutants are bothering you, it will be easier to figure out which device you should buy and where it should be placed.
- Decide whether you want a portable unit--or one that works through your existing heating/air conditioning system.
- Site it strategically. If you have a portable air purification unit, place its intake as close as possible the sources of pollutants. Push the clean air toward areas where people spend the most time. Make sure that the intake and the outlet are not blocked by walls or other obstructions.
- Keep it clean. Scrupulously follow the manufacturer's cleaning and maintenance directions.
When shopping, look for
- Ability to trap small particles. Because they can penetrate deep into the respiratory tract, small particles often do the most damage. The diameters of mold spores are 10 to 100 microns, while some smoke particles are less than 1 micron. (Human hair averages around 70 microns.) The best air purifiers, which can trap 99.97% of all particles down to 0.3 microns, are "ultra-high-efficiency."
- The right size. Air purifiers are rated by their Clean Air Delivery Rate, or CADR. To find the right CADR for your space, multiply the square footage by 0.75. For a hundred square foot room, for example, you would need a CADR of at least 75--or higher if you have higher than 8-foot ceilings. If you have an open floor plan, or multiple rooms, get two or more units.
- Easy maintenance. Make sure you'll be able to change the filters and clean the unit with minimal hassle.
- Variable fan speed. Look for models that allow you to set the fan speeds to match conditions.
- Energy efficiency. Check the wattage rating to make sure you're getting one of the most efficient models in your size range.
- Quiet operation. Test all the unit's fan speeds. How are the noise levels?
- Low ozone. Find out if the unit has been tested for ozone emissions, which are toxic in high concentrations. The federal recommended limit for ozone is 0.05 ppm (parts per million) for indoor air.
- There are several types of air purification devices:
- Mechanical filters physically strain particles out of the air.
- Electrostatic precipitators pull tiny particles in with a fan and take them out of the air with an electric charge, in the same way that static electricity attracts dust.
- Ion generators draw particles in with a negative charge, not a fan. Then the negatively charged particles are attracted to positively charged plates, where they remain.
- Ozone generators may actually aggravate breathing problems and are not recommended.
- Another approach is to equip a central heating system or air conditioner with medium or high efficiency filters. An air conditioning and heating dealer can tell you which type of filter is compatible with your system. If you go this route, you'll need to faithfully to change filters and do other maintenance chores. Failing to clean and drain an air conditioner's drip pans, for example, can encourage the growth of the same dangerous molds and bacteria you may be trying to eliminate. Also, since fans on air conditioners and heaters run intermittently, they cannot provide constant filtration.
If you are plagued by indoor air pollution, an air purifier can make you healthier and more comfortable.
...to your wallet
In sensitive households, the medical expenses that result from polluted indoor air can be huge, and the savings potential of a purifier can be great.
Not comparing all the costs. When shopping for an air purifier, make sure you consider not only the sales price, but also the cost of filters and other maintenance.
The Association of Home Appliance Manufacturers can help you begin your search for the right air purifier.