In recent times we have a lot more technologies at our disposal to use although they are based on the same basic rudiments. When you bought your home you bought along with it all the grime, grease, dust mites, animal dander, bacteria, mold, spores, and other stuff left behind by the previous owners of your house.
And let's not miss the additional mass of garbage that is brought in and day in and day out from simply walking in and out of the door each day and bringing in new uninvited guests. Uninvited guests including most likely the smog and pollution which has clung to your clothing, become stuck under your shoe from walking in the park, animal dander from your own pet or pets, and even insect parts that may find its way into your house (maybe even bits and pieces of them).
So unless you can afford to have a full-time maid working in your house or at least once a week or something, you're going to need to do the job yourself. Along with the rooms that have been cited already you might want to consider getting an air purifier for each room of your house.
If you would like to work out at home you 100% want to include an air purifier nearby because it's been substantiated that working out tends to cause our lungs to need even more air during more tough physical activities.
You'll also want an air purifier in your bedroom because when we sleep we also need more air. During those two activities we very much want to have the cleanest and freshest air possible.
Aside from your basic domestic appliances such as the vacuum or steam cleaner that's pretty much all you need as a commencing point. A no brainer right?