Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
To help inform our air purifier picks, we rounded up 14 of the most popular models at CNET Labs’ product testing facility in Louisville, Kentucky, where we put them through rigorous tests. Our goal was to determine which air purifiers offer the best performance in terms of particle removal efficiency, energy consumption, and quietness, while also evaluating their respective feature sets and value.
Particle removal test
The air we breathe is not just air. In fact, it is a combination of human-generated particles and naturally occurring particles. The former consists mainly of urban, industrial and automotive emissions of hydrocarbons, nitrogen oxides and combustion by-products, and the latter mainly represents smoke from forest fires, sulphates, soot and matter from volcanic activity around the world.
According to EPAsome of these microscopic solids and liquid droplets, which can be composed of hundreds of different chemicals, are so small that it is almost unavoidable to inhale them. PM10 and PM2.5, which are particles less than 10 and 2.5 micrometers in diameter, respectively, pose the greatest risk to human health once inhaled. They are distributed deep into the lungs and even into the bloodstream, disrupting the proper function of the lungs and heart.
“It’s the size that can enter our body, our lungs and our bloodstream,” Zhao said. “It’s the number one global environmental risk factor. It kills about 6 to 7 million people a year,” he said, due to cardiovascular or respiratory problems caused by particulate pollutants.
Our custom air cleaner test chamber uses a plexiglass front panel with a clear view and manual access with gloves, allowing us to manipulate the air cleaners, a particle counter holder for our control device, two fans to ensure proper mixing of air and smoke inside the chamber, vents for ventilation that ensure that there is a small amount of fresh air at all times, an ignition port for igniting smoke bombs outside the platform, and an exhaust vent that safely removes residual smoke from the chamber and building after each test.
The chamber is not hermetically sealed, but it is tight enough to ensure that no dangerous amount of smoke escapes into the environment. Our mission was to create an environment where we exposed each air purification unit to air saturated with particles of approximately the same concentration to evaluate how quickly and efficiently they return the air to breathing conditions.
We custom made smoke bombs, which were made of 50% potassium nitrate (KNO3), 40% sucrose (sugar) and 10% sodium bicarbonate (baking soda) and included a safety fuse for remote ignition. The sugar acts as our fuel source, while the potassium nitrate acts as an oxidizing agent, and the baking soda ensures that our dry mixture maintains a slow and steady burn.
Using a Temtop PMD331 particle counter, we were able to confirm that 5 grams of our dry smoke bomb mixture produced approximately between 590 million and 610 million particles per cubic meter. The device is able to count particles of different sizes, including PM2.5 and PM10, and records this data every 15 seconds. Although we are able to count particles of different sizes individually, we care about the total number of particles, which is the sum of all particles of different sizes.
We have prepared a 5 gram smoke bomb, which is ignited via the ignition port after installing the air cleaner and ensuring proper sealing. When the air in the chamber becomes saturated with particles (more than 580 million particles/m3), we turn on the air purifier in question. The data extracted from Temtop allows us to accurately monitor the impact that the air cleaner has on the particle count in real time.
Noise level
Using a decibel meter, we measured how loud the air cleaners were at low, medium, and high fan settings. This is especially important if you plan to have your air purifier on in your bedroom overnight and don’t want it to disturb your sleep. We performed this test in our sound improvement studio to ensure that the decibel meter is only picking up sound wave stimuli from the air cleaner, excluding other possible sources.
Energy consumption
To answer this question, we used a device called Kill-a-Watt and measured how much energy each air cleaner used at different fan settings. Knowing the energy consumption of your air purifier can affect your energy bill.
