Did you know that passive tobacco smoke contains over 250 harmful chemicals? Some air purifiers are specifically designed to remove far more of these harmful chemicals than others. This is an area that we really understand and that confuses some people more than most. Read our tips How to choose the best air purifiers to get rid of cigarette smoke?
What is the particle size of the tobacco smoke?
The most common particle size range in tobacco smoke (and, incidentally, also in marijuana smoke) is between 0.3 and 0.5 microns, but the majority of the most harmful particles are as low as 0.1 microns. To put this in perspective, you can place about 1000 microns on the head of a regular post.
Can an air purifier filter out such small particles?
This is the key question! In short, some can, many cannot. This is where choosing the right air purifier becomes most important. The most efficient type of air purifier for removing tobacco smoke is called the Hepa Air Purifier (Hepa stands for High Efficiency Particulate Separator). However, the gray area is that there are different classes of Hepa filters and not all of them are capable of capturing the finer and more hazardous particles mentioned above. These days, you can walk into most shops on the High Street like John Lewis or Argos and buy what appears to be a very impressive Hepa air purifier. Some are fairly inexpensive, others can cost hundreds of pounds. However, a closer look at the fine print (specification) almost always confirms that the Hepa filter inside the air purifier is only effective at removing particles as small as 0.3 microns and therefore unable to remove vast amounts of the most harmful air pollutants that are less than 0.3 microns.
This is not to say that basic hepa air purifiers with 0.3 micron filters do not have a role to play, they can still be very effective in removing major less harmful pollutants such as animal hair, plant spores and pollen.
So, will any air purifier with a suitable Hepa filter remove tobacco smoke?
Not exactly. The filter is only one third of the solution, putting all that steaming air in the filter is another third and removing the real smell of the smoke is the final third! If you think about it, no matter how good the Hepa filter is, if the fan that sucks the smoky air into that filter is too weak to pull all the air in the room towards it quickly, then the filter is almost irrelevant . So, ideally, the right combination is a good Hepa filter (filtering particles down to 0.1 micron), coupled with a fan motor powerful enough to suck out all that steaming air as quickly as possible (ideally about 5 times every hour in the specific size of your room). And finally, the last part of the puzzle is to remove the real smell of the smoke.
How to remove the smell of smoke?
Odor is not a particle, so even the best Hepa filters cannot catch it. Obviously, removing smoke particles (visible) is a huge part of the solution and the Hepa filter and fan power are critical for this. However, tobacco smoke also brings with it odors and harmful chemicals, most of which are so tiny they pass right through the Hepa filter. These odors and harmful chemicals must be adsorbed as they pass through the filter before they enter the room again. The only thing that will be effective for this is a charcoal filter located directly behind the Hepa filter. The type and size of the carbon filter is directly related to how much contaminants are adsorbed. Special air purifiers contain about a kilogram or more of real activated carbon. The cheapest and most resilient (and some not so cheap) devices we can find in our High Street stores contain just a symbolic gesture of carbon, often just a light, thin piece of sponge soaked in a little carbon.