Indoor Air

Indoor air covers everything we breathe when inside. We spend approximately 80% of our day indoors, so the air we breathe is incredibly important. The World Health Organisation states that 4 million people die every year because of indoor air pollution. We provide tips and advice on keeping you breathing safe when indoors using air purifiers and other life-hacks.

improve indoor ventilation air purifier combat covid 19 coronavirus

Hospital in Dhaka Uses Sqair Air Purifiers for COVID-19 Protection

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How a hospital in Dhaka, Bangladesh, quickly built COVID-19 patient isolation rooms using hospital beds, plastic cover and the Sqair HEPA air purifier. Following the COVID-19 outbreak, the CDC recommended hospitals isolate COVID-19 patients using airborne infection isolation room (AIIR). These are single person rooms with a negative air pressure … Read more

Best Place To Put Air Purifier in Room

The Best Place To Position Your Air Purifier

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Where should I place my air purifier? It’s a common question every air purifier owner has. Where to position an air purifier can be a difficult decision. How does position affects its performance? Is it best to put an air purifier next to a wall? This post answers the question … Read more

Study Finds Ionizers Increase Air Pollution

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A peer-reviewed study from the University of Texas finds that ionizers increase air pollution, creating formaldehyde, ozone, and particulate. This data contrasts sharply with claims from air purifier companies that market ionizers as magical machines. One company in China claims that their machine’s negative ions “remove PM2.5 particulate pollution and … Read more

How to protect yourself from wildfire smoke

3 Steps to Protecting Yourself From Wildfire Smoke

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Wildfires create a serious amount of smoke and air pollution. Smoke that can cause short and long term health impacts. That’s why it’s important to know how to protect yourself from wildfire smoke. Wildfire smoke is a form of air pollution. It contains dangerous VOC gases and small particles (PM2.5) … Read more

Can Activated Carbon Remove Formaldehyde?

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Can activated carbon filters remove formaldehyde and VOCs? Earlier tests from Smart Air found that carbon can reduce VOCs from cigarette smoke. But formaldehyde and VOCs in general are particular concern for many people. We put activated carbon filters to the test by ordering formaldehyde straight from the factory and … Read more

Air purifier filter living room clean filter entire apartment bedrooms doors open

Can One Air Purifier Clean an Entire House?

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Several people have asked me if they can use one purifier to clean their entire apartment or house. For example, can I put a large purifier in the living room and avoid having to put purifiers in each room? The benefits would be great. This setup would be easier, cheaper, … Read more

Should you put air purifier next to bed

Should You Sleep Next to Your Air Purifier?

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Is it better to sleep next to your air purifier? Does the location of the air purifier in your room matter? To find out, Smart Air did seven overnight tests to see if the air closer to the air purifier is cleaner than other spots in the room. Put to … Read more

Should I Run My Air Purifier All Day?

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Some purifier companies recommend running your air purifier all day. But is that really necessary? If so, isn’t running the purifier all the time a big waste of your filters and energy?

Test Method

To get to the bottom of it, I set a Smart Air Cannon on a timer to turn on for two hours everyday in a 13.5m2 Beijing bedroom:

Smart Air Cannon DIY Air Purifier Filter

I put a particle counter in the room to take measurements every minute. I did the test while I was on vacation, so there was no influence of me opening and closing doors.

Results

After six days, I came back and saw how long it took to the Cannon to clean the air each time it came on. Here’s what six days of data looked like for the small .5 micron particles:

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Over the six test days, the air in Beijing became progressively worse. But on each day, it was clear when the Cannon turned on and off. The dropoffs were sharp, showing the Cannon was working quickly.

I averaged over the six test days to find out how long it took the Cannon to clean the air on average.

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Conclusion

On average, the Cannon cut 0.5 micron particulate in half in 10 minutes. By 20 minutes, it removed 80%.

Bottom line: Should I Run My Air Purifier All Day?Powerful purifiers like the Cannon clean the air very quickly, so I see no need to run the purifier while I’m not at home.

Can I turn it off while I sleep?

The data can also answer another question a few people have asked me: “I don’t want to hear the fan while I sleep, so can I run it for an hour and then turn it off while I sleep?

In the tests, the air got dirty very quickly after the Cannon turned off (even though the windows and doors were closed). Dirty air is entering our homes constantly, even though we can’t see it.

 

Purifier closed room air dirty again

 

Bottom line: I do NOT recommend turning the purifier off while you sleep.

Open Data

As always, I’m publishing the raw data and more details on the methods below. I’ll also be publishing data from similar tests in a much larger room (30.5m2) and for tests when I’m at home and moving in the room.

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Smart Air is a social enterprise that creates simple, no-nonsense air purifier and provides free education to protect people’s health from the effects of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.