Air purifiers in the market nowadays tend to be rather bulky, to be placed in a room and connected to a power source. In addition, they tend to be rather costly, thus resistance from some to purchase and use these air purifiers. Hence, our project aims to build an air purifier that is portable, to be either placed in a wardrobe or carried around with people living in areas with polluted air. Moreover, we aim to create our purifier using products that can easily found/are cheap to purchase, making our purifier more affordable. We will 3D print the capsule body for each filter as well, so that each piece can be customised and manufactured at a low cost. It also allows for the replacement of filters only when needed, decreasing the wastage of resources.
Our air purifier aims to remove:
- Formaldehyde
Formaldehyde is often released during the construction of new wooden furniture and products which can be found in our homes. Though it is frequently used, it is a human carcinogen and has been found to be cancer-causing. In addition, formaldehyde gives off a strong unpleasant odour. Hence, our project aims to remove formaldehyde from wooden wardrobes, to remove the odour and reduce the harm on human health. We aim to remove formaldehyde by passing the air through activated carbon.
- Humidity
Since our filter is meant to be placed in wardrobes, we aim to reduce the humidity so as to prevent the formation of mildew and mold as they may also cause the wardrobe to smell over time. Currently, there are dehumidifiers present in the market using calcium chloride. We will be using silica gel beads instead of the common calcium chloride. An advantage is that silica gel beads will not clump up after absorbing moisture, avoiding the possibility of obstructing air flow which will happen if calcium chloride is used.
- Volatile Organic Compounds (VOCs)
The air pollution, specifically in China, is mainly caused by the burning of coal, resulting in high VOC emissions (primary pollutants). The VOCs emitted react with nitrogen oxides in sunlight to form smog-induced ozone (secondary pollutants). These VOCs are not only result in more air pollution, but are also known to cause adverse health effects. These include: conjunctival irritation, nose and throat discomfort, headache, loss of coordination and nausea, damage to liver, kidney and central nervous system and others.
Hence, our purifier aims to reduce the levels of VOC in the atmosphere and the air people breathe in. Baking Soda (sodium bicarbonate) can be used to remove such VOCs present in polluted air. Baking soda is alkaline, hence when the VOCs, which are mostly acidic, come into contact with baking soda, they get neutralised and hence VOCs in the air are removed.
- Carbon Monoxide (CO)
CO is a colourless, odourless and very toxic gas. It is often produced as a by-product in industrial manufacturing of chemical products. They also result from the internal-combustion engines exhaust gas, due to incomplete combustion to carbon dioxide. To remove this, we use a piece of filter drenched in water. Since CO is partially soluble in water, its levels in the air can be reduced In addition, at high temperatures, it can react with oxygen to form carbon dioxide, a relatively harmless gas.
- Airborne particulate matter
We plan to add N95 masks to act as filters to remove 95% of all particles that are at least 0.3 microns in diameter. We also aim to use pieces of filter paper soaked in water to remove dust and small, water soluble particles. These particles are extremely small and light, having the tendency to stay in the air for a longer period of time. Despite this, they are more harmful than bigger sized particles as they can bypass our nose and throat, lodging deep in our lungs. They irritate and corrode our alveolar walls, eventually impairing lung function. It has also been revealed that there is a significant correlation between number of fine particle pollutants and respiratory morbidity and mortality.
Sources:
https://www.cancer.org/cancer/cancer-causes/formaldehyde.html
https://www.medicinenet.com/staph_infection/article.htm
https://www.scmp.com/news/china/science/article/2166542/air-pollution-killing-1-million-people-and-costing-chinese
https://www.scmp.com/news/china/science/article/2166542/air-pollution-killing-1-million-people-and-costing-chinese
https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality
https://www.e-education.psu.edu/egee102/node/1975
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740125/
https://www.ncbi.nlm.nih.gov/pubmed/12401268
https://www.britannica.com/science/carbon-monoxide