Thanks for all the replies everyone.
So my goal is to make the air in the house as close to perfectly clean as possible. Unfortunately we have 3 smokers in the house who smoke at least a half a pack a day, and was wondering if 2 air purifiers (one is a 1000 Philips purifier with a 200 sq foot capacity and another is the 2000 Philips purifier with 300 sq coverage) would be able to effectively remove close to 100% of all the particles from the smoking and everything else, as in everything else I mean any and every particle (from pollution, household products etc) in the air down to the smallest possible micron size. The air quality index where I live is an average of 20 so I'm not too worried about pollution, but very much so about the second hand smoke.
@Dagl1 Nope the house normally has at least 3 windows open during the winter for fresh air.
My ultimate question, and I apologize for not being clear enough, is does the 99.97% filtration efficiency the purifier claims to be able to perform at include every single impure particle in the air or does the 99.97% rate only include particles as small as a certain micronic size? I wasn't able to find this anywhere. Since the filters state they're only able to remove particles down to a size of 0.3 microns, but are there a plethora of other particles much smaller than that (for example from a lot of second hand smoke) that pass right through the filter that could otherwise be easily filtered by other means such as plants? They say the activated carbon filter somehow absorbs the cigarette smoke because of the massive amount of surface area carbon has, but I'm not sure what particles that are less than 0.3 microns that the filter isn't absorbing. Also it says the purifiers has a ultra fine particle removal of 20 nm, does cigarette smoke consist of ultra fine particles smaller than 20 nm that should be filters? and are there any other methods of air purification that can filter 1 nm particles or is that possible/necessary?
(edit) The purifier not only has a HEPA filter for removing dust, etc, but also an activated carbon filter which has the role of absorbing smoke and gas particles, and I'm not sure if the 20nm or 0.3 micron value applies to the carbon filter or to the HEPA filter or vice versa.