With climate change, devastating wildfires that have become the norm in some parts of the world, and the weakening of environmental regulations on pollution, it makes sense that you’d be concerned about what’s in the air you breathe every day. And while you may think you’re safe if you just stay inside, according to Michele Ann Cassalia, director of marketing at the Asthma and Allergy Foundation of America (AAFA), “the indoor level of pollutants can be two to five times higher than the outdoor levels.” Along with simple methods like keeping rooms well ventilated and removing sources of pollutants where possible, an air purifier can go a long way toward improving your air quality.

Regarding the wildfires currently burning up and down the West Coast, Roger Maxfield, a pulmonologist and professor of medicine at Columbia University Irving Medical Center, says there are gases and particles in smoke that can cause irritation and inflammation in the lungs, especially for people with preexisting respiratory conditions. If you are in an area affected by wildfire smoke, first make sure your doors and windows are tightly closed. Reza Ronaghi, a pulmonologist at the UCLA Health Santa Monica Medical Center, advises sealing any gaps or cracks with old clothes or duct tape. Robert Gillio, a pulmonary critical-care physician, says for best results you’ll want your air purifier “running 24/7 at the highest speed possible to clean as much air as possible without the noise being disruptive.” Family physician William Lang, chief medical officer at WorldClinic and former director of the White House Medical Unit, stresses replacing your purifier’s filters regularly. He also points out that, because air purifiers only reduce the concentration of smoke particles — not remove them entirely — in areas with dense smoke, the concentration may still be too high with a purifier, and you may have to consider relocating.