General Questions
Not necessarily. Many people live comfortably without one. They're most helpful for those with allergies, pets, limited ventilation, or specific air quality concerns. If you're satisfied with your air quality and don't have specific issues, you may not need one.
Not meaningfully. While NASA research showed plants can remove some VOCs in sealed chambers, in real rooms, you'd need hundreds of plants to match what a small air purifier or opening a window accomplishes. Plants have other benefits (aesthetics, mood), but air cleaning isn't one of them at practical quantities.
Use your range hood when cooking. Cooking generates significant particulate matter. A venting range hood removes these particles far more effectively than any air purifier. It's simple, effective, and often underused.
Air Purifier Questions
For best results, yes. Air purifiers work by continuously filtering air. Running only occasionally allows particles to accumulate. Modern purifiers are designed for continuous use and use modest electricity—typically less than a standard light bulb.
HEPA stands for High-Efficiency Particulate Air. A true HEPA filter captures 99.97% of particles 0.3 microns in diameter. Be wary of "HEPA-like" or "HEPA-type" claims—these don't meet the actual standard. Look for "True HEPA" or specific grades like H13.
HEPA filters don't remove odors—they capture particles. For odors, you need activated carbon. The amount of carbon matters; thin sheets have limited capacity. Even with carbon, source control (cleaning litter boxes, ventilating when cooking) is more effective than trying to filter out continuous odor sources.
CADR (Clean Air Delivery Rate) measures how much filtered air a purifier delivers, in cubic feet per minute. Higher CADR means faster, more effective cleaning. It's more reliable than vague "room size" claims. For good performance, your purifier's smoke CADR should be at least 2/3 of your room's square footage.
Specific Concerns
Yes. HEPA filters effectively capture wildfire smoke particles. During smoke events, keep windows closed and run your purifier at higher speeds. Indoor air with a running HEPA purifier can be dramatically cleaner than outdoor air during smoke events. Creating one "clean room" is a practical strategy.
It can reduce airborne allergens like pollen, dust mite particles, and pet dander. Most allergy sufferers find them helpful as part of a broader strategy including regular cleaning, allergen-proof bedding, and humidity control. They won't eliminate symptoms, but may reduce them.
Seal air gaps where smoke enters (around doors, outlets, pipes) and run an air purifier with both HEPA and activated carbon. This won't eliminate infiltration completely but can significantly reduce it. Document the issue if you need to involve management.