Smoke contains multiple types and sizes of particles and gases that every air purifier can not remove them efficiently. There are some relevant factors and calculations you need to know before selecting an air purifier for removing smoke from the air. Don’t get confused further by air purifier commercials where they claim their unit is for pollen, dust, pet dander, smoke, mold spore, odors, bacteria, and even viruses. But, this is not true completely because the particulates and gases are different in sizes, and not every air purifier filter traps them equally. Our comprehensive step-by-step guide will help you on how to choose an air purifier that can remove smoke effectively from air.
What is Smoke: A Quick Overview
Any smoke contains two types of substances: particulates and gases. Particulates in smoke are mainly a mixture of solids and liquid droplets. These particles are range from 0.1 microns to 10 microns in diameter on different types of smoke. Different types of gases are produced from different types of burning fuel. Though the most common gases in smoke are Carbon dioxide, Carbon monoxide, and sulfur dioxide.
For reference, a human hair is 50-70 microns in diameter on average.
Particle sizes in different types of smoke:
Check our reviews >> Best Air Purifiers for Smoke & Odor
How to Choose an Air Purifier for Smoke
Now you understand the nature of different types of smoke. Let’s begin on how to choose an air purifier that is very much capable of removing smoke with 3 simple steps.
Step 1: HEPA filter
The first thing you need to look at is the primary filter. Only select an air purifier for smoke that uses the HEPA filter for its primary filtration system. HEPA which stands for High-Efficiency Particulate Air filter can trap tiny particles that are sized down to 0.3 microns at a 99.97% removal rate.
The MERV rating of the HEPA filter is 16 and higher. Some air purifiers use HEPA-type or HEPA-like filters at lower MERV ratings than standard HEPA. We don’t suggest choosing these cousins of HEPA filter air filter. So, check it carefully before selecting one.
Step 2.a: High airflow rate (CADR)
There are lots of air purifiers that use a standard HEPA filter, but not all have a decent airflow rate that can remove smoke effectively. CADR or Clean Air Delivery Rate is the most significant factors to choose an air purifier. It’s a measurement standard for the performance by an air purifier which is developed by AHAM. Commonly the airflow rate or CADR is expressed as cubic feet per minute (cfm) or as a cubic meter per hour.
To remove smoke efficiently from the air you need higher CFM air purifiers. The higher CFM value will remove smoke faster; thus, you will get excellent area coverage.
However, exactly how much CFM do I need for my room? Question on the mind, right? We have a tool, but before start using it, you need to know a little bit about air exchange rate is also known as ACH or ACPH.
Step 2.b: Select your air exchange rate (ACH)
The air exchange rate is the most significant factor when you calculate your required CFM. You won’t let your air purifier couple of hours to remove smoke from your room. Here comes the ACH or ACPH. Air Changes per Hour (ACH) is how many times an air purifier can clean the entire volumetric air from a closed space. For example, 2 ACH means the air purifier filter the air from the specific room 2 times per hour or a complete air clean needs 30 minutes. The higher it will be, the faster you will get clean air.
As smoke contains highly concentrated particles and gases you need to select the ACH higher for faster air cleaning. We suggest selecting it at least 5 for effective smoke removal.
It’s like the CADR is the horsepower, and the ACH is the acceleration for an air purifier.
Now Let’s find out the CADR with flexible ACH selection.
Enter your room dimensions and select the ACH 5 at least. Now you will see the calculated CADR value. Very easy, right?
Let’s say the room size is 20 x 15 ft with a standard 8 ft ceiling. By selecting ACH 5, we get the calculated CFM 200.
Or, you can use your calculator to find it out. Here is the formula:
CADR = [(ACH x L x W x H) / 60] cfm (dimensions are in feet scale)
Now, you got two key components, One is True HEPA filter, and another is the calculated CADR in CFM. For us, the CADR is 200 cfm.
Note: Some air purifier manufacturers listed their product by using cubic meter per hour in CADR. Be careful when you select air purifier by CADR.
Now let’s go to the final step:
Step 3: Thick layer of activated carbon filter
As we have seen earlier in the table, every type of smokes contains multiple gases, and we need to remove them also. Here comes the activated carbon filter. A standard HEPA filter works excellently against particulates, but unfortunately, they are not good at trapping odor and gases.
Activated carbon also known as activated charcoal has a unique nature of absorbing gas and odorous compounds. A thick layer of activated carbon filter will increase the filter surface significantly; thus, the efficiency will increase.
Select only those air purifiers which use a large number of activated carbon pellets in their odor filter. Some use a basic thin sheet of an activated carbon filter. These are not suggested, especially when you choose an air purifier for smoke.
So, you get the recipe to choose an air purifier to remove smoke effectively.
The summery: True HEPA filter + Calculated CADR for smoke + Thick layer of Activated Carbon filter.
Now, with this recipe, your searching for an air purifier for smoke is now much narrower, and you can find one quickly.
Alternatively, you can browse our Air Purifiers for Smoke Archive to read reviews, and to see our top picks.
Additionally, you can look at the features on air purifiers:
Particle Sensor: To get real-time air quality status from your air purifier, you need a built-in particle sensor. It will also help to run the air purifier with different fan speeds based on the surrounding air quality, which is also energy convenient.
Extra filters: Some air purifiers have an optional ion generator that traps particulates and removing them from the air by fall down to the ground. It will increase only 8% efficiency in CADR. Though it might produce a small amount of ozone which is lung irritant, read our blog post on Different Air Cleaning Technologies.
Wifi Connectivity: You might be a tech enthusiast, and you want to monitor and control your air purifier with your phone. Air purifiers are getting smart nowadays, and you can find the feature on some.
Not all air purifiers are all-in-one solutions as they advertised. You must choose an air purifier carefully when you need it for a specific reason. We hope this step-step guide will help you in selecting an air purifier for smoke. If you loved this article, share it with your loved ones who are very concerned about indoor air quality. Happy Breathing!