How to shop for top rated air purifiers: a Shanghai expat's guide
So, how to choose a suitable air purifier, aka air cleaner, to combat Shanghai air pollution? In our Shanghai Pollution article, we discussed some issues related to buying air purifiers in Shanghai.
Here we will go more into the technical details of air purifier machines and offer some advice on how to use them to best clean your indoor air.
A first suggestion is to buy air purifiers in Shanghai as quickly as you can. When air pollution spiked here in late 2015 and early 2016 sales of air purifiers in Shanghai soared by 300%, causing some air purifier stocks to run out, and prices to increase.
We have a list of suppliers of air purifiers in China for you to compare, as well as useful resources and related news items at the end of the article.
It is quite clear from experts that top quality air purifiers should include a HEPA (High Energy Particulate Arresting) filter to improve your indoor air quality.
Based on the United States Department of Energy (DOE) standard, HEPA filters remove a minimum of 99.97 percent of particles 0.3 microns in diameter. The European Union's standard, EN 1822:2009, breaks HEPA filters into several classes with efficiencies ranging from 85 to almost 100% for 0.3 μm sized particles.
This particle size is much smaller than the maximum size of 2.5 μm associated with the hazardous PM2.5 pollutant we often hear about. PM2.5, aka fine particulate matter, is considered dangerous to our health, as it is small enough to breathe deep into our lungs and enter our bloodstream, as opposed to PM10 which includes particles from 2.5 to 10 microns in size which are mostly exhaled from the lungs.
The size of 0.3 μm was chosen for testing as it is considered the most penetrating particle size (MPPS), ie. the size of particle which filters have the most difficulty in blocking from passing through. Efficiency of the HEPA filter can actually increase for some types of particles smaller than 0.3 μm; although not all.
HEPA filters can trap various kinds of particulate matter that cause or aggravate asthma and allergies including:
Some air purifiers claim to use a HEPA ‘like’, ‘style’ or 'type' filter, but do not meet HEPA standards. So don't be fooled; make sure to purchase a machine with a true HEPA standard or above filter.
Chemical fumes, gases, chemicals in smoke, odor molecules, and some viruses, are much smaller than 0.3 µm and can pass through HEPA filters. It is important, therefore, for your Shanghai air purifier to also have an activated carbon filter.
Activated carbon has a very large surface area which attracts and absorbs gasses, fumes and vapors.
When air is pulled through the air purifier, the activated-carbon filter holds on to pollutants including:
Carbon filters also extend the life of the HEPA filter by trapping larger particles before they can reach it.
Important points to compare when purchasing an air purifier in China:
Unfortunately, most foreign brands of top rated air purifiers in China are more expensive than in the West. The author bought a purifier with multiple filter layers for allergies manufactured by IQAir of Switzerland in Canada for about RMB 6,000, whereas in China it costs about RMB 14,000. Despite its high price, the CEO of IQAir expects China to become its biggest global market in 2019.
Other top rated air purifiers targeting the expat community in Shanghai include Blueair from Sweden, which was recently acquired by Unilever. Its purifiers, using their unique HEPASilent technology, sell between RMB 3,500 and 7,000, depending on the coverage area. Alen Air of the US is another popular brand in China selling various models between RMB 4,000-7,000. And Dutch company Philips sells air purifiers here from RMB 2,000-5,000.
Several Japanese and Korean air purifier brands also sell well in China, but mainly target the local population so don’t have very good English marketing materials.
These include the Japanese brand Sharp with their built-in humidifiers selling between RMB 1,500 to 5,000. The author purchased one model with a coverage area of 40-60 m2 in 2013 for RMB 4,100. In 2019 the same model was purchased for just RMB 1,700. Not only had the price dropped by almost 60%, but it was upgraded to include smart control through an app. The humidifier is especially useful in Beijing which is extremely dry during the winter months. Of course humidifiers can also be purchased separately quite cheaply.
An American expat, Thomas Talhelm, and his Beijing company Smart Air have been promoting their Do It Yourself (DIY) cheap air-purifiers to the expat community around China.
Instead of buying an expensive air-purifier in China, this company recommends buying HEPA filters by themselves and strapping them to a fan. Their own extensive test results show that PM2.5 levels in the room will be reduced as effectively as when using the more expensive purifiers.
Smart Air sells the kit for you to assemble yourself, or describes how you can purchase the parts on your own. This very smart idea gives those on lower budgets a way to reduce particulate matter (PM) levels indoors and therefore is a great contribution to making cleaner air more affordable for everyone in China.
However, Smart Air's inference that this method proves other air-purifier companies in China are “trying to pump people for insane profits” is a bit simplistic. The original Smart Air product is only a HEPA filter and does not include the activated carbon and other filters found in more expensive machines. Adding such filters to the Smart Air product will increase the price. Without the casing it can also be noisier than other air purifier machines.
Smart Air recommends the standard HEPA filters they provide be changed within less than 2 months when operating 24 hours a day, while the long-life true HEPA filters in the more expensive air-purifiers, when combined with activated carbon and pre-filters, only need to be changed once every 2-5 years according to their manufacturers.
Another Shanghai expat startup, Mila, has come up with its own subscription model for renting air purifiers in Shanghai. This could be a cost effective choice if you are in Shanghai for just one to two years.
As the air purifier market in China grows and matures, foreign brands have been reducing their prices and more local Chinese brands such as MI from Xiao Mi have brought out machines selling for under RMB 1,000.
Unfortunately, few of these local brands have good English service in Shanghai, so it is hard to tell if their technology and service is as good as established Western brands. We, however, include some in the list below.
In early 2016 a report from the Shanghai Quality Inspection and Supervision Bureau showed that several cheap Chinese air purifiers, including some models made by Xiaomi, had failed quality tests.
Consumers were reminded to look for the required labeling of coverage area, clean air delivery rate (CADR) and noise index on the packaging before deciding which model to buy.
Further tests of air purifiers around China conducted by the national General Administration of Quality Supervision, Inspection and Quarantine in the first half of 2016 found that one-quarter of the them were substandard. The failed models were mostly smaller local Chinese air purifier brands.
These national tests included tests conducted in Shanghai which found air purifier models manufactured by, sold by, or branded Mitsubishi, Baomi , Novowater, ReFinAIR, Somputon, Zhejiang Benyuan Appliance, LongYea, were substandard for various reasons.
The Shanghai Consumer Rights Protection Commission carried out their own tests on 20 popular air purifier models sold in Shanghai in late 2016, and found several models failed standards for filtration efficiency for formaldehyde including models from Panasonic, Hitachi and several local brands.
China grades filtration efficiency for pollutants between 35 and 50% as Grade C; between 50 and 65% as Grade B, and 65% and above as Grade A. Anything less than 35% efficiency is below standard. Manufacturers must also label their efficiency rates on their machines clearly for consumers, and must achieve at least 90% of this claimed amount when tested independently.
In 2017 the Shanghai Consumer Rights Protection Commission tested 20 models for their CADR rating and found that a model by Dyson achieved a very low score of just 134 (CADR unit of m3/h).
In subsequent tests published in late 2018 and early 2019 by the Shanghai Consumer Council and the Association of Environmental Protection Industry of Shanghai all models passed standards for particulate matter filtration efficiency, but several failed standards for formaldehyde or methylbenzene removal. A Panasonic model failed to reach the minimum standard for formaldehyde removal, and a MI model failed the minimum methylbenzene removal requirement.
Many of those that did pass, however, only achieved the minimum C grade of 35 to 50% removal efficiency. And several models failed reaching the minimum 90% of their label's claimed efficiency amounts.