6 symptoms of poor air quality

"Investing in an air purifier is also an affordable way to reduce the amount of allergens and irritants in the air in your home. "

The problem is that we really do not have suitable evidence from a scientific perspective if air purifiers are as good as they suggest, and the cost in replacing the filters so regularly mounts up...
Is it really a good solution, or just something to believe in if you do indeed fell better at a given time.
A few points from the link below to consider:

"There is very little medical evidence to support that air purifiers directly help improve your health or alleviate allergies and respiratory symptoms. "

"Air purifiers that utilize HEPA filters can capture particulates the size of the coronavirus. However, the actual efficacy of it at preventing someone from getting the virus is still unknown, as the rate of transmission may be faster than the air purifier can capture the particulates "

"Most filters on the market are designed to capture particles like dust, smoke and pollen, but they don’t catch gases like VOCs (volatile organic compounds) or radon that may accumulate from adhesives, paints or cleaning products. "