Winter’s closed windows, slushy boots and sweaty undershirts—plus the scent of dinners past—can yield a stinky house. Keep your inside air fresh and safe with these tips from Lisa Beres, author of Just GREEN It! Learn to Create a Healthy Home.

Swap out the air filter in your HVAC system every three months to maintain fresh airflow and remove other pesky particles that can carry bacteria and viruses. Brush your pet frequently (preferably outside) to reduce the shedding of odiferous hair and other allergens. And while you might be tempted to light vanilla-scented votives, candles can contain soot and other chemicals. Create a natural air freshener by mixing 10 drops of an essential oil like lavender with 2 cups of water, and spritz your way to freshness.