Seriously, get a HEPA rated air filter. Speaking as someone who has some serious lung issues, it's literally life changing/saving. Honeywell sells a number of models, cost is between 150-270 USD, depending on the size/amount of air you want moved.
It won't be as good as a purpose-built machine, but it will be far better than nothing at all.
TheWirecutter found it reduced particulate matter in a room by 87%, if you do it right. They also make clear important caveats about this method -- in short, this works in a pinch, but probably should not be used in place of a purpose-built filter if you want one for year-round use. https://www.nytimes.com/wirecutter/reviews/best-air-purifier...
I'm not sure how accurate it is or isn't. It reacts to the filters, for example, or if I hold it in front of the filter it'll reach a very low number, conversely if I take it to other parts of the house or outside it'll increase. I've done a few trials like that and it seems directionally accurate, but I can't speak to the numerical accuracy.
It measures PM 2.5 and 10 and has a button to show graphs over time for ~12 hours. Battery life is pretty good, I usually leave it detecting on the charger, but I've had it in handheld mode for several hours and stayed above 80%. It's super simple to use.
One thing I don't like about it is that it has a cheap plastic hinge that is supposed to let it stand up, but it broke on me after a couple uses. It doesn't seem to matter though if it's standing up or laying down, it still reads pretty much the same.
I wish it had a way to export data to my computer or maybe an app.
Be sure to note the airflow direction arrows on the filter.
One thing to keep in mind though is most filters have an expected direction of airflow, which does matter both to its efficacy and efficiency.
I personally use Winix machines. I don't think it matters much in terms of efficacy which brand you use, so, consider the cost of replacement filters here. The machines I bought were around $200 each, and worth every penny, IMHO.
My machines are both made for environments with pets, so they have a pre-filter to catch large things like dog fur, and they also have an activated carbon filter to pull odors out of the air. The carbon filter is quite effective. Unfortunately, I was able to test this first-hand, by observing that I could no longer smell dog poop after about 10 minutes of the machine running in the room said poop was in.
I wouldn't worry about silly features like accompanying smartphone apps, or any kind of "ion technology." IMO, that stuff is mostly marketing fluff, and just adds complexity to what should basically be a small fan with a filtered intake.
I've found my machines to be very effective in cleaning the air inside my apartment. I've been lucky enough so far to not have any issues from the Bay Area smoke, despite having asthma and allergies. I credit that to my HEPA filter machines, as well as wearing an N95 mask outside whenever the AQI is too high.
As an aside, I once put one of my machines (each rated for around 300 sq. ft., IIRC) inside my bathroom, which is no more than about 30 sq. ft., for a while. Eventually, the air in there smelled so clean, it literally took me back to the days when I used to regularly work in a class 1,000 (ISO 3) electronics clean room. "Class 1,000" means the air inside is supposed to contain no more than 10^3 particle >= 0.1 µm in diameter per m^3 of air. Once you've smelled the air inside a decently high level clean room, you'll recognize it when you come across it again. It smells like a glorious whole lot of nothing, which makes my allergies happy. :-). For reference, ordinary, unfiltered, not-apparently-dusty air typically has about 10^6 particles >=0.1 µm per m^3.
A handheld particle counter helps a lot.
What you really want to know is how long it takes to recirculate the entire air volume of the space you're interested in. But, for a typical dwelling that has ~10-ft ceilings and isn't too leaky, that square footage number is a really good guideline.
I'm guessing the table lists filtration for a single pass through the filter. But through constant circulation a greater reduction in air particulate can be achieved. Anyone know this for certain?
Your typical 1980s construction home likely does not have mechanical ventilation, the only inlet would be for fresh air to facilitate the combustion in the furnace (alongside an exhaust for carbon dioxide and carbon monoxide).
This should work.
If you have a good filter but it is not managing to clean the air in your apartment, the most likely problems are that your apartment is too large for the filter's capacity, or that your apartment leaks air in from outside so that your filter can't counteract the effects of the leaking.
> Typically it is harder for a filter to clean the air in your apartment when you are bringing in extra outside air
That was my point. Bringing in outside air would be a luxury.
Btw just ordered passive filters for the windows for super cheap- perhaps that will move the needle on how much outside air we can bring in while maintaining indoor AQI.
Still curious about the positive pressure idea. If it’s effective, I’d expect someone to productize it.
Seal window crack however which way you can. Tape and a block of wood with a 3” circular hole? Voilà.
Might be a good idea to pre-filter nozzle air to keep your HEPA for the small stuff.
And have a good stock of replacement vacuum filters. And earplugs...
Energy auditors will install a “fan door” to build pressure inside your home to smoke-test for air leaks. This is the same concept, except filtering the incoming air and helping to ensure your air-leaks are 1-way: out.
But this is all no competition for a stiff wind.