Poor indoor air quality is a common in homes and offices around the world. Poor air quality can affect the health, mood and productivity of those indoors. Here are three different ways to improve indoor air quality, and the advantages of each.
Indoor Air Quality Overview:
Before we get to the solutions, it’s worth listing out the common types of pollutants that lead to indoor air quality.
- PM2.5 pollution: PM2.5 air pollution from outside can make its way into homes and offices, and indoor sources such as cooking or smoking can lead to higher indoor PM2.5
- VOCs: Gases in the air that are more prevalent in newly renovated flats. They can be emited by new furniture, wood and paints, as well as from smoking.
- CO2: High people occupancy in homes or offices can lead to high CO2 levels.
1. Central air and ventilation systems for fresh air
HVAC systems or central ventilation systems are used to either bring in outdoor air or recirculate air in a room or building. The idea is that air is treated centrally, then distributed to multiple rooms in a building. Most HVAC systems provide a central way to heat or cool the air, and allow recirculating and mixing indoor air with outside air so as to lower CO2 values. However, not all are able to purify the air.
This means HVAC systems are useful for lowering indoor CO2 levels (by bringing in outdoor air). Bringing in outdoor air also has the added benefit of pushing out any unwanted indoor pollutants such as formaldehyde or other VOCs. HVAC systems can be useful, for example, when dealing with newly renovated flats by pushing out VOCs.
Pros: Can be used to reduce indoor VOC & CO2 levels. Discrete and quiet.
Cons: High operating costs, difficult to retro-fit in buildings, often does not filter for PM2.5. Furthermore, it can bring polluted air from outdoors in.
2. Air Purifiers
An increasingly popular choice, air purifiers work by purifying the existing air within the room instead of bringing outdoor air in. Compact and lightweight, purifiers are also portable and can be moved from one location to another. Essentially, polluted air is drawn into the purifier and is sent through a HEPA filter, with clean air produced after.
This means that air purifiers are extremely effective at filtering small pollutants like PM2.5 within indoor environments. In fact, Smart Air tests have shown that the Sqair air purifier can remove nearly 100% of PM2.5 in a closed room within 2 hours. Besides this, air purifiers can also be fitted with a carbon filter to remove harmful VOC effectively. A comprehensive method for improving indoor air quality, air purifiers are effective for day-to-day usage in all environments.
Pro: Easy to install, easy maintenance, no retro-fitting, portable, effective against PM2.5, dust and allergens, can reduce VOCs if fitted with carbon filters.
Cons: Unable to reduce indoor CO2 as it does not ventilate the room unlike ventilation systems, takes up space in room.
3. Fresh Air Systems
Standalone air ventilators draw outdoor air into the room, but sends them through a filter first. Unlike central ventilation systems, they are much simpler (usually ‘standalone’ and not requiring any other equipment to be operational). They are also often only seen in China to address a unique situation faced by Chinese households – High indoor formaldehyde (requiring ventilation to alleviate), but highly polluted outdoor air (requiring filtering before being drawn into the room).
By purifying a room through allowing filtered outdoor air to enter, air ventilators can be effective at reducing not only CO2 and VOCs, but PM2.5 as well. The filters in the air ventilator trap PM2.5, while the room is being ventilated with fresh air with lower concentrations of CO2 and VOC.
Pros: Brings in filtered outdoor air which reduces PM2.5, CO2 and VOCs.
Cons: Filters need frequent replacement given that they are used for highly polluted outdoor air, outdoor air may be too hot or cold which requires significant energy to heat or cool, requires drilling a hole in wall, more expensive than a purifier.
Which Method is Best Improving Homes & Office Indoor Air Quality?
Office Indoor Air Quality
For office buildings or other areas with high people capacity, HVAC systems may be preferred as they can help keep CO2 and VOC levels down. However, they may still need to be complimented with air purifiers if the HVAC system does not include air filters.
Home Indoor Air Quality
For individual homes, fresh air systems can be installed to reduce all three of CO2, VOCs and PM2.5. However, they’re cumbersome to install, not widely available outside of China, and have high running costs due to high electricity consumption and frequent filter changes.
As such, the easiest and simplest solution to improve indoor air quality in homes is to use an air purifiers. They’re readily available, easy, can be placed anywhere in a room and very affordable. They can filter out PM2.5 and VOCs, but not CO2. CO2 can still be reduced when using an air purifier by partially opening the windows.