Air pollution kills around 7 million people every year. Most of these deaths occur in developing countries, where solid fuels are often burned in poorly ventilated spaces. However, between 26,000 and 38,000 of these deaths occur in the UK.
Britons spend more than 80% of their time indoors, whether at home, at work, at school or on the go. It is therefore crucial to ensure that the air inside these enclosed spaces is safe to breathe.
Over the past few years, there has been an ever-expanding range of air purification devices on the market, especially when it became clear that COVID was an airborne disease. Some devices operate by thermal or photocatalytic oxidation, others by adsorption, filtration, UV germicidal irradiation, ion generation and electrostatic precipitation.
Despite their scientific-sounding names, none of these technologies remove all indoor air pollutants and many generate unwanted chemical pollutants, as detailed in a recent report by the UK Government’s Scientific Advisory Group for Emergencies ( Wise).
For example, ionizing devices give particles an electrical charge that causes them to fall onto surfaces, pulling them out of the air. However, they can also produce ozone through their operation. Electrostatic precipitation devices also charge particles to remove them, but can produce nitrogen oxides and ozone.
Chemical oxidizers actually use an ozonizer or a mixture of chemicals to release ozone or other oxidizers directly into the part. Since ozone and nitrogen oxides are harmful gases, some of these devices simply displace one pollutant with another.
The Sage report concluded that air purification technologies were likely to provide only limited benefits in properly ventilated spaces and were not necessary unless there were specific risks (such as busy road outside, making natural ventilation more difficult). The report also concluded that, where necessary, technologies using filtration or germicidal UV were most likely to be beneficial if used correctly.
One problem with air purifying devices is that they are not regulated in the UK. Anyone purchasing such a device should rely on the information provided by the manufacturer to determine how effectively it removes pollutants.
Devices tend to be tested in carefully controlled laboratory conditions rather than in a typical occupied building. The issue of secondary pollutant formation is often not addressed and guidance on where an air purifying device should be placed for best results is often lacking.
The onus is too much on the consumer to weigh the benefits of air cleaning technologies and decide which one they should choose.
Simplify consumers’ lives
To make this easier for consumers, the government should create an independent, accredited organization to test the safety and effectiveness of these devices. Testing should be done in a realistic indoor environment to ensure each device is safe to use and maintain as it ages.
And manufacturers should provide clear guidance on how to use and maintain their air purifying devices. The operation and maintenance of these devices should be as simple as possible.
Manufacturers should also provide operating parameters, as they currently do for household appliances, such as refrigerators and stoves. Parameters would include things like noise (if the device is too loud, there’s a chance people will reject it), maintenance costs, the volume of a space that can be cleaned, and the efficiency of the cleaning. removal of pollutants. These should be provided as a standard checklist, allowing consumers to easily compare devices.
Even with these changes in place, consumers will still have to consider whether indoor spaces or rooms really need air purifying technology. This is perhaps the most challenging aspect, given that many consumers will not have the expertise or equipment to figure out whether or not to clean the air in their home.
For most homes, natural ventilation is sufficient, especially after activities that cause high indoor emissions such as cooking and cleaning. Using an extractor hood in the kitchen when cooking and an extractor hood when using the bathroom will also help. If a building is located on a busy road, it may be necessary to open windows on the other side of the building or during off-peak hours.
A relatively inexpensive way to help homeowners assess whether they need air cleaning in addition to ventilation would be to purchase a carbon dioxide monitor. A recent report indicates that carbon dioxide concentrations consistently above 1,500 parts per million suggest poor ventilation and that cleaning the air could be beneficial.
Finally, air purification will only ever be a temporary solution. For most buildings, the best solution is to remove air pollutants from the outdoors and ensure there are adequate window openings to provide sufficient ventilation.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Nicola Carslaw receives funding from UKRI (NERC and EPSRC), EU COST and the Alfred P. Sloan Foundation.