Start of the Auto mode test
I conducted the following test in my test room located in District 4 of Saigon right on the border of District 1. The AQI reported by the US Consulate was at 159 (roughly 70.9 micrograms). Kaitura recorded the AQI in my test room at 137 AQI or about 57 micrograms at the beginning of the test. I then turned on the Xiaomi Air Purifier 2 on auto mode.
One hour later, the AQI at the US Consulate increased to 169 (90.3 micrograms). This is one of the highest readings I have experienced in Saigon.
End of auto mode test
I ran the test for 6 hours on auto mode. As you can see below, in this mode the air cannot get clean. The final reading recorded at 22 micrograms. By Chinese and WHO AQI standards, this is safe. By US AQI standards, this is twice the safe level.
For some Expats, this may be acceptable but after living in Shanghai for a year, I prefer to follow the stricter AQI standards. Now granted, I did not run the Xiaomi Air Purifier 2 at the highest fan mode. SmartAir conducted a similar test if you are interested. SmartAir even stated that using auto mode, the air will be unsafe 86% of the time. In the post, they mentioned that after three hours at the highest setting, the Xiaomi Air Purifier 2 reverted back to auto mode. For me, I noticed that the air purifier actually turned off on many occasions after three hours.
Hence, if you are relying on the Xiaomi Air Purifier 2 to keep your room at a safe air level of PM2.5, you either are going to have to get up every three hours or have another air purifier on the side.
DIY SmartAir Original to the rescue
After this test, I decided to give the smaller SmartAir Original DIY air purifier a run again to see if it can get the room to a safe PM2.5 level. Roughly two and a half hours later, the Original got the AQI down to 46 ending at 21 AQI four hours later. That is a safe 6 micrograms. Read more about my first test of the SmartAir Original air purifier.
Conclusions
Does this mean you should throw out your Xiaomi Air Purifier 2? Definitely not, I love it. If I am cooking or the need the air to be cleaned fast, I turn on the Xiaomi at the highest setting. I only use it at highest setting so I tend to turn it off after the air is at a safe level. The Original can be used all day but it will take longer to get the room at a safe level. Side by side, they both work well together and remember, you are going to need at least two air purifiers in an apartment or house.
SEAACT will also provide locally make air purifiers at a lower cost utilizing locally-made fans and imported HEPA filters. In a future blog post, I will test one of the locally made fans that I am actually using today to clean the air in my apartment. We will make these available for purchase by the end of November, 2017. As of July, 2018, we were not able to register a company to sell HEPA filters in Vietnam. To stay under the radar, it is best to order the HEPA filters directly from SmartAir and build your DIY air purifier with the Senko model pictured above.
Until the next test, stay safe and wear your PM2.5 masks.