GNDphotography/E+ via Getty Images
Portable air cleaners aimed at curbing indoor spread of infections are rarely tested for how well they protect people and very few studies evaluate their potentially harmful effects. That’s the upshot of a detailed review of nearly 700 studies that we co-authored in the journal Annals of Internal Medicine. Many respiratory viruses, such as COVID-19 and influenza, can spread through indoor air. Technologies such as HEPA filters, ultraviolet light and special ventilation designs…….Continue reading….
Source: The Conversation
.
Critics:
As with other health-related appliances, there is controversy surrounding the claims of certain companies, especially involving ionic air purifiers. Many air purifiers generate some ozone, an energetic allotrope of three oxygen atoms, and in the presence of humidity, small amounts of NOx. Because of the nature of the ionization process, ionic air purifiers tend to generate the most ozone.
This is a serious concern because ozone is a criteria air pollutant regulated by health-related US federal and state standards. In a controlled experiment, in many cases, ozone concentrations were well in excess of public and/or industrial safety levels established by US Environmental Protection Agency, particularly in poorly ventilated rooms.
Ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation. It can also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections—even in healthy people. People who have asthma and allergy are most prone to the adverse effects of high levels of ozone. For example, increasing ozone concentrations to unsafe levels can increase the risk of asthma attacks.
Due to the below average performance and potential health risks, Consumer Reports has advised against using ozone producing air purifiers. Some manufacturers falsely claim outdoor and indoor ozone are different. Claims that these devices restore a hypothesized ionic balance are unsupported by science. Ozone generators are used by cleanup contractors on unoccupied rooms to oxidize and permanently remove smoke, mold, and odor damage, and are considered a valuable and effective industrial tool.
However, these machines can produce undesirable by-products. In September 2007, the California Air Resources Board announced a ban of indoor air cleaning devices which produce ozone above a legal limit. This law, which took effect in 2010, requires testing and certification of all types of indoor air cleaning devices to verify that they do not emit excessive ozone.
Other aspects of some air cleaners are hazardous gaseous by-products from ozone-generating units, noise level, frequency of filter replacement, electrical consumption, and visual appeal. Ozone production is typical for air ionizing purifiers. A high concentration of ozone is dangerous, although most air ionizers produce low amounts, low rates of ozone reduce the effectiveness. A build up can cause detrimental health effects especially for vulnerable people.
The noise level of a purifier can often be obtained through a customer service department and is usually reported in decibels (dB). The noise levels for most purifiers can vary and may be dependent on fan speed. Frequency of filter replacement and electrical consumption are the major operation costs for any purifier. There are many types of filters; some can be cleaned by water, by hand or by vacuum cleaner, while others need to be replaced every few months or years.
Sometimes suitable filters are only sold by the manufacturer for a high cost, some have DRM control so only replacement filters authorised by the manufactuere can be used. In the United States, some purifiers are certified as Energy Star and are energy efficient. HEPA technology is used in portable air purifiers as it removes common airborne allergens. The US Department of Energy has requirements manufacturers must pass to meet HEPA requirements.
The HEPA specification requires removal of at least 99.97% of 0.3 micrometers airborne pollutants. Products that claim to be “HEPA-type”, “HEPA-like”, or “99% HEPA” do not satisfy these requirements and may not have been tested in independent laboratories. Air purifiers may be rated on a variety of factors, including Clean Air Delivery Rate (which determines how well air has been purified); efficient area coverage; air changes per hour; energy usage; and the cost of the replacement filters.
Two other important factors to consider are the length that the filters are expected to last (measured in months or years) and the noise produced (measured in decibels) by the various settings that the purifier runs on. This information is available from most manufacturers.
Leave a Reply