Feb 12, 2021 20:00:00

The result of actually testing the air cleanliness of the top 5 air purifiers is this, how to choose an appropriate air purifier?

A good air purifier removes viruses in the air, but choosing an air purifier is important for its effectiveness. Many brands have developed a wide variety of air purifiers, but actual tests have shown that popular brand products do not always excel in air purifiers.

Is an $ 800 purifier best to clean your home's air? Marketplace tested 5 top brands and their claims | CBC News

https://www.cbc.ca/news/business/portable-air-purifier-tests-marketplace-1.5900782

Jeffrey Siegel, a professor of engineering at the University of Toronto, Canada, calls the air purifier market a 'marketing jungle.' Mr. Siegel collaborated with the Canadian TV show CBC Marketplace to test how high the performance of popular brand air purifiers is.

The products tested were Levoit LV-H132 , Germ Guardian AC5350B , Dyson Pure Hot + Cool , BlueAir Blue Pure 211 , and Honeywell HPA 160, a total of five brands. In Canada, sales of air purifiers are increasing due to the epidemic of the new coronavirus infection (COVID-19), and the products of the above five brands are said to be gaining popularity among air purifiers.

Siegel also tested DIY air purifiers made with fans and filters, along with products from popular brands. Many air purifier

filters are equipped with HEPA filters that remove at least 99.97% of pollen, mold, bacteria, dust and suspended particles, but DIY air purifiers use the cheaper MERV-11 filter. , The material cost was 70 Canadian dollars (about 5700 yen) in total.

CBC Marketplace purchased 15 air purifiers from 5 brands for testing. In collaboration with Mr. Siegel, he burned incense sticks in a room of 24 square meters and investigated the air purification power called clean air delivery rate (CADR) . CADR measures the time it takes an air purifier to remove pollen, smoke, dust, etc. from the air, and is usually expressed in cubic feet / minute or cubic meters / hour.

The results of actually testing 6 air purifiers are shown in the figure below. The vertical axis is CADR shown in cubic meters / hour, and the horizontal axis is lined up with each air purifier. The higher the number, the more air purifier. Indicates that the power is excellent. The Blue Air Blue Pure 211 at about 560 cubic meters / hour is by far the best performer, and the others are not much different from DIY air purifiers.

The DIY air purifier for about 5,700 yen is about 160 cubic meters / hour, but the Dyson Pure Hot + Cool for 50,000 yen is about 140 cubic meters / hour, which is lower than that. Mr. Siegel recommends an air purifier with an air purifying power of 200 cubic meters / hour or more even in small and medium-sized rooms, but Dyson Pure Hot + Cool is also below this value.

Dyson engineer David Hill, who received the test results, explained that CADR is just one indicator for measuring the effectiveness of air purifiers. Dyson has developed a unique ' (PDF file)

POLAR test ' that is different from CADR, and the POLAR test automatically responds by detecting 'the intelligence of the air purifier' and 'whether the air in the room is dirty or clean'. Measures 'ability to circulate' and 'ability to circulate clean air in the room'. While CADR is also an important part of air purification, the ability to detect and remove air pollution is also important, Hill said.

On the other hand, experts say, 'CADR is an internationally recognized benchmark and the most important metric.' 'Air purifiers that combine a high-performance filter with a low air flow rate have a low CADR, and even if the filter efficiency is low, the higher the air flow rate, the higher the CADR,' says Francis, a researcher of indoor air.・ Mr. Offerman said.

In this way, it is believed that the reason why there are expensive air purifiers with low CADR is that they have functions other than the air purifying function. For example, Dyson Pure Hot + Cool has a heater function, which incurs a large cost. In addition, the Germ Guardian AC5350B, which costs about 14,000 yen, has a UV-C light that 'kills bacteria'.

However, UV light expert James Murray analyzed the UV dose and UV-C power of the Germ Guardian AC5350B and concluded that it was 'not enough to significantly reduce the amount of bacteria in the air.' I have. Murray warned that while there are good UV-C products on the market, there are companies that make random claims.

Based on the above, the following four points are listed as points when choosing an air purifier.

・ First, check the CADR value published on the website.
・ According to Mr. Siegel, the CADR suitable for small and medium-sized rooms is 200 to 300 cubic meters / hour.
-Some companies publish CADR in imperial units instead of metric systems, so in that case , convert the units here .
・ Select an air purifier that matches the size of the room based on CADR.

Experts, including Siegel, also said that ion generators and plasma air purifiers that emit ozone, which can be dangerous to the respiratory system, should be avoided. In addition, the CBC Marketplace cautions that photocatalytic oxidation (PCO) produces formaldehyde , acetaldehyde , nitrogen dioxide, and nitric oxide.