I live in a city with bad air pollution and no central HVAC system. I have two air purifiers and an air quality monitor. Both air purifiers are effective in reducing the particulate matter count. But unless they are run at full speed 24 hours a day the indoor air quality doesn't stay within a safe range. If they are run at less than full speed then a safe particle count is only reached after many hours. When a window or exterior door is opened the particle count shoots up quickly.

I want to be able to freely open doors and have a bearable amount of noise. It's possible that other air purifiers run quieter but it seems noise level and effectiveness are directly correlated. Are there any other measures to increase the effectiveness of an air filtration system? Should I seal doors and windows with weather strips? Our home has fans in both the kitchen and bathroom. When running these fans the air quality gets worse. If the bathroom/kitchen doors are kept well-sealed and closed would it help?

  • When you mention "air quality" are you specifically just testing/measuring particulate? Also, just speculating, I would think with the fans running, it would only acutely worsen the particulate count, but by not allowing the air to pool or stop moving you have a greater chance of filtering out these moving particles. Feb 12, 2016 at 12:56
  • Yes, I'm mostly concerned with PM2.5 and PM10 particle counts. Feb 12, 2016 at 14:38
  • A respirator might be an option. A little tough to sleep in, but at least it's quiet.
    – Tester101
    Feb 12, 2016 at 14:46

2 Answers 2


A filtered fresh air supply(intake) would work for this. You can filter the air in your living space all you want, but any leak or opening could allow dirty air to leak in.

If you filter outside air and blow the filtered air inside, your living space will be very slightly pressurized. Then any leaks would just be your clean air blowing outside, not the other way around.

An air filter with inlet and outlet ducts would be optimal for this setup, and set up the filter inlet to the outside.

  • I think air pressure is the key because I can feel a draft coming in from our front door. Would I need a bigger fan than the bathroom/kitchen fans? Or at least run it at a higher speed when those two are running? Should I put this intake fan at the opposite end of the house so that air flows through to the kitchen? Feb 12, 2016 at 23:16
  • Yes, you need a fan flowing at least as much air as your kitchen ventilation fan. The location of the intake does not matter that much, as long as the intake is greater than the exhaust, the air pressure will find its own path to push outward.
    – Netduke
    Feb 16, 2016 at 14:44

When you say you have 2 air purifiers I am guessing they are electrostatic to trap the particulate matter on the grid. The small/ portable units can only move a limited amount of air so you may need additional units. When your stove fan or bathroom fans are on they pull air out of the home so fresh air has to enter some place. Find out where your vents are and put one of the units in line with the incoming air if possible that would reduce the rise in particle count when you use the fans. Remember to regularly clean the grid if electrostatic it will trap more when clean.

  • One of the air purifiers is a HEPA filter. The other I'm not sure about. Feb 12, 2016 at 14:36
  • HEPA and ULPA filters do a very good job of removing particulate matter that is why they are used in clean rooms. They require a huge airflow and with that the increase in noise. You might look into electrostatic they move more air with less noise but require regular cleaning.
    – Ed Beal
    Feb 12, 2016 at 14:43

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