Assessing indoor air quality: Air cleaners

The quality of indoor air and how to assess it are increasingly raising concern, whether this is related to the efficiency of air-conditioning systems or of air cleaners. Air-cleaner market is doing fine. According to the Environmental Protection Agency, Americans spend up to 90% of their time indoors; this might partially explain the sales of USD 450 million worth in air cleaners annually. However, thousands of models exist and it is difficult to assess how efficient they are: the Food and Drug administration (FDA) does not regulate the units and even the asthma and allergy foundation have not certified any devices with their "asthma friendly" label. The only clinically tested devices are those with high-efficiency particulate air (HEPA) filter. Elizabeth Cotsworth, director of EPA's Office of Radiation and Indoor Air, said that air cleaners could be used as an adjunct to ventilation systems but could not remove all indoor pollutants and Jill Notini, a spokeswoman for the home appliance manufacturers group, advises consumers look at filter efficiency and performance, using an industry benchmark called the clean-air delivery rate.