25-31 May
Informal presentation 1 – 28 May
Draft 1 of our prototype was presented to the MnT Team. After discussion, we decided to focus on purifying second-hand smoke at its source (the smoker) rather than after dispersion (the non-smoker such as neighbours). Some points for consideration are listed.
- The possibility of a 2-in-1 product was using the concept of invertible fans which can generate suction in opposing directions.
- Using water as a filter. This can be implemented as a water curtain or damp cloth in our prototype.
- The differences between tubular and flat filters, in terms efficiency, air flow and ease of instalment and replacement. Further research was done in the next week.
Due to school-wide restrictions on smoking on campus, incense smoke will be used as a replacement for cigarette smoke. Key components, including particulate matter and smell-causing Volatile Organic Compounds (VOCs), are similar in both.
Preliminary testing – 30 May
We conducted a preliminary test using the XiaoMi air purifier 3, installed with the green formaldehyde filter. The aim was to determine the efficiency of market air purifiers in removing the smell from incense smoke.
A representative drawing of our set up is shown. The stick of incense was place within the body of the air purifier, to ensure smoke would pass through the filters. Our take-aways are as follow.
- No white fumes were observed at the outlet, showing that the HEPA filter was effective at removing particulate matter.
- The smell of incense smoke was strong at the outlet, though less significant than when unfiltered. The carbon filter was not very effective, despite being marketed to remove formaldehyde which is one of the main odour-causing chemicals in incense smoke.
Additionally, we investigated the effect of water using a damp cloth over the outlet. The smell was reduced slightly. However, we could not be sure if this was due to the effect of water, or solely because the additional layer of cloth had hindered air flow out. Further research of the effectiveness of water was done is subsequent weeks before deciding whether to incorporate it into out product.
Note: Progress in the first 3 weeks were relatively slow as members were away at different period for their Overseas Learning Trips. Most work was done remotely.