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Smart Air Indoor Air Quality Audit in 3ESpace

Date of audit: 27/05/2017
Audit conducted by: Yap Choon Khin

Paddy Robertson

Air quality monitor: Dyloc DC1700 Pro

AirVisual Node

Audit location: 3ESPACE, Beijing Jiaodaokou, Xinhua New Culture Building, 5th floor
Air quality measurement outside premises: 115 µg/m3
Corresponding Air Quality Index (outdoors)[1]: 182
Air quality inside premises: 70 µg/m3
Corresponding Air Quality Index (indoors): 158


Outside air pollution

Smart Air visited the 3ESpace co-working space on 27th May 2017. We used a Dylos DC1700 to measure the outdoor air quality along the front and sides of the 3ESpace building.

The average outdoor PM2.5 concentration was 115 µg/m3, which equates to an Air Quality Index (AQI) of 1821. This AQI level corresponds to an ‘Unhealthy’ air quality level.

We then made visual inspections of the surroundings and found the following possible sources of local pollution which could affect 3ESpace’s indoor air quality:

  1. Pollution from the busy road in front;
  2. VOC and large dust from the construction works behind the building;
  3. VOCs and PM2.5 from smokers outside the building main entrance.

However, we also noted that the 3ESpace building is generally surrounded by houses, which are unlikely to produce large sources of pollution.


Inside air

We tested the indoor air quality in 6 of the 3ESpace rooms, and the average indoor PM2.5 concentration was measured as 70 µg/m3. The corresponding AQI is 158 (US), which coincides with an air quality level of ‘Unhealthy’.

Using the AirVisual Node, we measured indoor CO­2 levels, and found the average to be 578 (a typical outdoor CO2 reading is around 400-600). From this, we can conclude that the premise is well ventilated and there is unlikely to be a large build up of VOCs or other gases inside.

Inside, we used the Dylos DC1700 device to check for leaks around windows. The windows are well-sealed with a low risk of them leaking PM2.5 into the building. However, the windows were open in one of the small incubators and rooms. Having windows open when purifiers are running drastically reduces their effectiveness at removing air pollution.

See Figure 3 and Table 3 in Appendix 1 for more detailed results on the indoor air quality tests we performed.

Purifier habits

6 Xiaomi purifiers had been installed by the 3ESpace staff on the premises 5 months ago. Unfortunately, during the time of our inspection, only one of the purifiers was turned on. The Xiaomi in question was in its ‘auto’ mode, which we’ve previously tested and found to be extremely ineffective.

We discussed purifier operation habits with the 3ESpace staff, and found that purifiers were only turned on when the pollution ‘looks bad’. Furthermore, some of the staff did not believe that air purifiers do anything to reduce air pollution. It is important that all the staff understand the benefits and importance of having an air purifier indoors, and turning it on whenever the AQI reaches ‘unhealthy’ levels.


The Cannon

Using the Smart Air Cannon purifier, we performed a simple 30 minute test in one of the 19m2 meeting rooms. During this test, the Cannon reduced the room’s PM2.5 concentration from 71µg/m3 to 23µg/m3, a reduction of almost 70% in just a 30 minute period.

Figure 1: PM2.5 levels when testing the Cannon

We recommend that affordable yet effective air purifiers like the Cannon be used to lower indoor PM2.5 levels.


We were surprised to find that although 3ESpace had 6 purifiers installed, not all of them were turned on. We highly suggest that existing purifiers be turned on when the outdoor AQI level is above 100.  For the larger rooms, small household purifiers like the Xiaomi would not be adequate to clean the entire space. Therefore, we suggest 3ESpace install larger industrial units like the Smart Air Blast purifiers in these rooms.

Below are room-by-room suggestions for purifier installation:

Room Action needed
R1 Turn on 2 Xiaomi purifiers when required
R2 Install Smart Air Blast purifiers
R3 Install Smart Air Blast purifiers
R4 Turn on 1 Xiaomi purifier when required
R5 Turn on 2 Xiaomi purifiers when required
R6 Turn on 1 Xiaomi purifier when required

Table 1: Recommended action for rooms visited


We recommended that all staff attend a Smart Air workshop, a great way of educating them on to the air pollution situation in Beijing and how they can protect themselves from air pollution.

It is also important that 3ESpace delegate one person to oversee the purifier operation in the entire co-working space. He/she is recommended to check the AQI twice a day and turn on ALL purifiers and close windows whenever the AQI level increases above 100.


Next Steps

We hope that with our analysis and recommendations, 3ESpace will be able to breathe in more clean air. For any queries or discussions regarding the audit, we are contactable via email ([email protected]).


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Smart Air is a social enterprise and certified B-Corp that offers simple, no-nonsense air purifiers and provides free education to protect people from the harms of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.

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