Smoke may smell good, but it's not good for you. If you are healthy, you are not usually at major risk from smoke. Still, it's a good idea to avoid breathing smoke if you can help it.
Smoke is made up of a complex mixture of gases and fine particles produced when wood and other organic matter burn. The biggest health threat from smoke comes from fine particles (also called particulate matter or PM). These microscopic particles can get into your eyes and respiratory system, where they can cause health problems such as burning eyes, runny nose, and illnesses such as bronchitis. Fine particles also can aggravate chronic heart and lung diseases—and are linked to premature deaths in people with these chronic conditions.
Some people are more susceptible than others:
How to tell if smoke is affecting you: Smoke can irritate the eyes and airways, causing coughing, a scratchy throat, irritated sinuses, headaches, stinging eyes, or a runny nose. If you have heart or lung disease, smoke might make your symptoms worse.
It's important to limit your exposure to smoke, especially if you may be susceptible. If you must use a wood stove or wood burning fireplace, protect yourself and use an air purifier to clean fine particles from your indoor air. Some air purifiers offer filters that are specifically designed to eliminate particles emitted by residential wood stoves and wood-burning fire places.
For additional information on the health effects of wood smoke, visit http://www.airnow.gov/index.cfm?action=smoke.smoke2
Source: EPA


