Reddit mentions of HOLMES True HEPA Air Cleaner and Odor Eliminator with Digital Display for Large Spaces, HAP759-NU, Room

This really depends on a lot of things. The kitchen is usually the primary source of indoor air pollution. I have a PM2.5 monitor and cooking bacon and eggs puts it off the chart. It's extremely important to have good ventilation when you cook (which most kitchens don't have). I've also encountered terrible indoor air quality around town in restaurants, etc.

If you live in Salt Lake and don't want to die young a HEPA filter is a sound investment. They are not crazy expensive and I've verified with my particulate counter that they do work very well. I have purchased probably a dozen of this one because its cheap and effective but there are other options that are more quiet. I have two in my home and the rest around the office or given away to friends. They have an updated model that I have not used here. I will sometimes travel with one if its convenient.

While I'm on the subject. This is unrelated to what you said but here is some more pertinent info about Utah air quality:

Car air filters surprisingly do a good job and I read very low pm2.5 concentrations even when driving down i-15 on an inversion day in traffic, but there are also air scrubbers designed to run off the 12v in your car.

If you're going outside for longer than 15 minutes and especially if you are exercising, wear a P100 rated mask such as this one.

During inversion season I take my air quality meter around and test all over the place and post the results to twitter if anyone is interested. The numbers reported by the state are accurate in the sense that they give a baseline by which to measure trends over time, but they are completely inaccurate in terms of what you will actually encounter when you go outside. You can expect to encounter up to DOUBLE what the state reports. A local hero has set up a network of sensors that will give you a better idea of what is going on. You can find the info at purpleair.org you can also host your own sensor.

Thousands of people are dying each year due to our poor air quality. It is taking YEARS off of our lives. So the last thing I'm going to say is please support initiatives to expand public and alternative transportation, promote clean energy, and to eliminate major sources of pollution in the valley. Demand from your candidates that they make air quality a priority. Other cities around the world have made real positive impacts on their air quality just by trying, so it's not impossible.