Carpets may trap pollutants like dust mites, pet dander, mould spores, and dirt, keeping those from circulating in the air, but these can be disturbed during activity. For a healthier environment, vacuum several times a week, ideally using a vacuum with a High Efficiency Particulate Air filter. You should also clean them annually, ensuring that it dries well after a steam clean to prevent mildew. Wool carpets can be a healthier option as they are hypoallergenic.