Across the country this holiday season, families and friends will gather around fires in woodstoves or fireplaces. But how you build that fire – and what you burn – can have a significant impact on air quality and health, both inside your home and out.Whether you’re using a woodstove, pellet stove, or your fireplace, seeing smoke from your chimney means your fire isn’t burning efficiently or cleanly as it could. Woodsmoke contains fine particles – also called fine particle pollution or PM2.5 — which can harm the lungs, blood vessels and heart. People with heart, vascular or lung disease, and older adults and children are more at risk. Here are some simple tips for building cleaner-burning fires this holiday season: