The smoke haze from bushfire has hung over large parts of New South Wales since November. This has prompted people to rush out and buy air purifying machines to try to keep the smoke at bay in their homes.
The advice from the government is to shut your doors and windows and stay inside. Especially if you have pre-existing respiratory issues. Nevertheless, demand for air purifiers has been so great that shops are reporting that they are running out.
Galvan Cheung at Good Guys in Alexandria in Sydney said stores had very few left.
“We are almost completely sold out across the range from every manufacturer,” he said. “Our regular suppliers can’t guarantee stock of air purifiers until next year. Unless you are willing to drive to Coffs Harbour or Port Macquarie – they are the only stores that have any stock. Stocks are low in every state because they’ve all had problems with bushfires.”
But what features should you look for in buying one and do they even work?
What does an air purifier do in a Bushfire Situation?
These are electrical devices that work by plugging into the main socket. They filter the air in your house and take out the harmful toxins and microparticles and then help blow the clean air around the home. They are not the same as humidifiers or air conditioners.
What should I be looking for Bushfires’ safety?
Experts agree that you must make sure your device has a Hepa filter (it stands for high-efficiency particulate air). It works by pushing the air through a fine mesh that then collects harmful particles such as pollen, dust mites, tobacco smoke, and, crucially for Australians, bushfire smoke.
Chris Barnes, the household product expert at Choice.com.au, said a Hepa filter was vital for trapping harmful smoke.
“A Hepa filter is something which is important to trap fine particles,” he said. “Smoke does tend to be fine particles so you need a really, really good filter.” Hepa filters need to be changed every six months or so depending on the model.
It’s also important that the purifier has a fan that can blow the fresh air around the house or around the room you’re trying to clean.
“You must have good airflow around the purifier because otherwise it will just sit there and clean that corner of the room,” Barnes said. “The better units will typically have their own fan but you can give it a helping hand by using a pedestal fan to blow the air around.”
Some also come with a carbon filter but that was not as important as the Hepa filter.
What’s on the market?
Cheung says that Good Guys sell four brands – DeLonghi, Dyson, Cli-mate, and Breville. You can pick up a desktop device for about $70 but they become progressively more expensive depending on how big the space is and how sophisticated you want your technology to be.
The Dyson Pure Hot+Cool purifying fan heater sells for around $900 and, as the name suggests, is also a mini aircon unit. It claims to be able to simultaneously heat or cool a whole room while advanced purifiers remove fine particles such as allergens and pollutants. Dyson says it can purify the air in an 81 square meter room. It also comes with an app that you can use to monitor air quality levels in your home.
Another popular machine in Australia is the Arovec air purifier which sells for $168.99 on Amazon. It claims to neutralize dust via a preliminary filter, eliminate cooking and smoking smells, and filter unhealthy air.
The website 10reviews.com.au rates the US-made Levoit LV-H132 machine, which retails at around $140, as one of the best domestic devices. Amazon.com.au is currently sold out of these machines. Another highly recommended one is the Germ Guardian, made by another US company, Guardian technologies, which is almost $700.
Do they actually work?
Experts agree broadly that air purifiers do help to keep harmful air particles out of your home. But as with any consumer choice, it depends on how much you want to pay. Does Barnes say that Choice has been working on a product review of air purifiers and taking advice from its UK sister organization, Which?
He said it was probably worth paying a bit extra to get a more expensive machine.
“Which? found that the real cheapies didn’t really do the job particularly well,” he said.
Dr. Christine Cowie, a respiratory health expert from the Centre for Air Pollution, Energy and Health Research and the Woolcock Institute of Medical Research, told Guardian Australia last week air purification could help.
“There are a few studies that indicate air purifiers are useful in reducing particulate matter indoors but they do need to be fitted with a Hepa filter,” Cowie says.
Be aware that every purifier has a set amount of area it can purify. “One small air purifier will not do a whole house,” Cowie says. However, the industrial air filtration system by Euromate is the best in the business.
NSW Health was more skeptical in its response to Guardian Australia.
“Air purifiers can reduce particles in a smaller indoor area such as a single room that is closed off from other areas, however, there is limited evidence of their effectiveness during bushfire smoke events.”
Does aircon do the same job?
If you have a reasonably up-to-date split aircon unit it will help to keep the air inside your home cleaner because it will have a good filtration system.
“Because you close up the house anyway when you are using your air conditioning and the indoor units have a filter, it will have some effect,” Barnes said. “The more recent units have better filtration systems so if you have reasonably up-to-date one it is better than nothing.”
1. The air purifiers you buy in most stores are not effective at filtering bushfire smoke out of the air.
This is because air purifiers are only as good as filters. In desperation, we’ve heard many stories of people going to stores to buy whatever they had left in stock and then calling us in frustration when they realize they are ineffective for smoke.
A Google search on air purifiers can be anything but helpful with so many models all looking much the same; a rectangular plastic box with a couple of vertical panel filters, some lights on the front, and a particle sensor that promises to adjust the speed of the air purifier based on air quality in the room.
The reality is the majority of air purifiers are designed for dust and allergen removal, not smoke. They may reduce the particle concentrations but they do not have high capacity activated carbon filters with only grams instead of kilograms. The carbon filter is the primary filter required for smoke adsorption and filtration. Without this type of filter, you are still left with gases (carbon dioxide, nitrogen dioxide, and volatile organic compounds).
Inaccurate Air Purifiers:
It’s also important to know the air quality sensors incorporated in many air purifiers are generally inaccurate. Providing “good” readings when there are still relatively high levels of PM or VOCs. The sensors are very low cost and have a short operating life. So you end up with a system giving you readings you can ignore. In addition to this air quality sensors should not be incorporated into air purifiers. The air near an air purifier should be better than anywhere else in the room. A better option is to use a freestanding air quality monitor like Euromate’s Co2 Monitor.
2. Air purifiers that are made from materials like plastic off-gas chemicals and contribute to poor air quality in your home
This can be a serious issue for people who are particularly chemically sensitive. And it’s unfortunate we hear stories of people suffering as a result of the air purifier they have purchased. Our air purifiers are made from safe materials (steel and aluminum) that won’t off-gas in your home.
3. There is a much bigger, ongoing problem with air quality that many people don’t understand
Unfortunately, even when bushfire season is over, air quality in our cities is a growing problem. Due to population and pollution growth – this is because PM2.5 particulate matter from bushfire smoke is also emitted by motor vehicles. And makes its way into our homes. Coal-fired power stations are another contributor to poor air quality.
If you are wondering whether you will still get value out of your air purifier. The answer is absolutely yes – particularly if you live in a large city or near a main road or motorway.