I’ve always wanted to invest in a full home air purification system, but they are $$$$. So i have these placed around our home - specific bedrooms! This brand is MD recommended - has HEPA filters that remove bacteria, germs, pollen, dust, mold, pollutants, smoke, etc etc. These are my top recommendation for every home! ** the difference in these filters is the sq footage they cover!** LTKhome LTKsalealert