Gas Appliances and Asthma

I saw an old patient of mine yesterday who has pretty significant asthma.  She had been really well controlled for the last couple of years until a month or so ago when her symptom frequency started to increase.  She was having more trouble exercising and had used her nebulizer a few times as well.  The only thing she noted that was different was that some family had come for an extended visit.  She told me her grandsons had been playing around with the gas fireplace and she had been cooking more with her gas range and gas oven.  We checked her lung function and it had fallen by about 40% since her last visit!

This illustrates an important and often under-recognized point about asthma and indoor air quality.  Though we think often of outdoor air quality, checking for levels of ozone, sulfur dioxide, and diesel exhaust particles, indoor pollutants can lead to respiratory problems as well.  Indoor flames from gas fireplaces, gas ranges and ovens, wood burning stoves and unvented kerosene or gas space heaters emit nitrogen dioxide, a respiratory irritant.  Nitrogen dioxide has been clearly shown to worsen symptoms in asthmatics and COPD patients.  If you have fuel burning appliances in your home, the EPA recommends these steps to reduce harmful indoor pollutants:

• Properly ventilate a room where a fuel-burning appliance is used and use appliances that vent to the outside whenever possible.
• Do not idle the car inside your garage.
• Have the entire heating system — including furnace, flues and chimneys — professionally inspected and cleaned annually.
• Always open the flue on your fireplace before building a fire to ensure that smoke escapes through the chimney.
• Make sure the doors are tight fitting on your wood-burning stove and follow the manufacturer’s directions for starting, stoking and putting out the fire.
• Follow the manufacturer’s directions for proper fuel use on unvented kerosene or gas space heaters and keep the heater properly adjusted. Open a window slightly or use an exhaust fan in the room while using the heater.
• Install and use an exhaust fan over a gas stove and vent it outdoors.