COPD and Humidity

Medically Reviewed by Zilpah Sheikh, MD on December 22, 2023
Written by Stacy Simon, Shawna Seed
5 min read

Weather that’s too humid or not humid enough can make it harder to breathe when you have chronic obstructive pulmonary disease (COPD), a lung disease that gets worse over time. Changes in humidity and temperature can trigger a flare-up. Symptoms that may get worse include coughing, wheezing, shortness of breath, and tightness in your chest.

Humidity is the amount of water vapor in the air. It’s usually higher in the summer and lower in the winter. The baseline depends a lot on the climate where you live. Try to keep levels inside your house between 30% and 50%. You can measure it with a hygrometer, which is like a thermometer for humidity.

Humid air feels thick and dense. It makes your body work harder to breathe. You may need more oxygen, and you may feel tired and short of breath. Humid air also helps grow mold and dust mites, as they thrive in a moist, warm environment. Both can cause allergies that trigger COPD symptoms.

The dew point is a tool that can indicate the level of humidity in the air. It means the temperature that the air must be cooled down to in order to reach a relative humidity of 100%. Here, the air can’t hold any more water as vapor (its gaseous form). If it continues to cool down, water vapor will come out of the air as liquid, usually in the form of fog or rain.

The smaller the difference between the actual temperature and the dew point temperature, the higher the humidity will be. And higher the dew point, the more water vapor molecules will be present in the air.

If there’s more moisture in the air, it results in reduced oxygen levels. While some people’s COPD symptoms get better in humid weather, less oxygen may make it harder for others to breathe.

If there’s a higher dew point and less available oxygen, people with lung conditions can develop bronchospasms. These happen when your airways contract and go into spasm. You might have a hard time breathing, start wheezing, or begin to cough.

Because COPD already affects your airways, reduced oxygen levels due to humidity can further worsen your symptoms.

We tend to feel the humid, sticky effects of a high dew point in the summer. But dew points can still be high in colder months. On clear and cold nights without much wind, frost or dew can form. You may not notice that the dew point is high, due to the lack of muggy weather, but a high dew point during cold weather can still harm your lungs. Air that’s cold and dry can irritate your airways if you have COPD. It may lead to wheezing, shortness of breath, or coughing.

Home dehumidifiers are useful in damp parts of the house, such as basements. They can remove 10-50 pints of water from the air each day. The water drips into a basin that you need to empty and clean with bleach to keep mold away. Choose a larger one for more flexibility; you can always adjust it down.

Measure the humidity in your home to keep it at an ideal level and prevent overuse of the machine. Be sure to clean your humidifier often, or bacteria can grow in the tank, which can make you sick.

On the other hand, low humidity causes the air to feel dry. Dry air irritates your throat and sinuses and can help spread viruses such as the flu and COVID-19.

If the air in your house is dry, a humidifier adds moisture in the form of vapor or mist.

Humidifiers are useful in winter when your heating system is on, which dries out the air. They’re good to have all year round in very dry climates. They come in many sizes, ranging from a tabletop model that can handle one room to a console that spreads moisture to larger areas. You can also have one built into your central heating system to humidify your entire house. No matter which type you use, clean it often to keep mold and bacteria away. Follow the directions that come with the unit.

Tips for using your humidifier include:

  • Use distilled water.
  • Change the water as often as every day.
  • Unplug and clean the tank every 3 days with hydrogen peroxide or another disinfectant if the directions say so. Then rinse the tank.
  • Change filters at least as often as the directions say, more often if they’re dirty.
  • Consider replacing old humidifiers, which can build up deposits that make them hard to keep clean.

You can’t change the weather, but you can take steps to help you breathe easier and prevent flare-ups when humidity is not ideal:

  • Consider a humidifier for your home or just your bedroom.
  • Consider a dehumidifier if you have a damp basement.
  • Stay inside with your windows closed, away from pollen and other things you may be allergic to.
  • Work with your doctor to get the right medications or inhalers to manage your allergies.
  • Stay active even when stuck inside to stay healthy and reduce shortness of breath.
  • Drink plenty of water to help control your body temperature. Keep hydrated no matter how wet or dry it is outside. Drink enough water so that your urine is clear to light yellow.

Check the current dew point. You can check the dew point to see how the weather will feel. You can find it in your daily forecast information or search for it online.

Refer to the COPD dew point comfort scale. Generally, most people find that dew point correlates to how easy or difficult it is to breathe, based on these values:

  • Under 55 is pleasant
  • 56-60 is comfortable
  • 61-65 is slightly sticky
  • 66-70 is uncomfortable
  • 71-75 is oppressive
  • Higher than 76 is miserable

Plan to stay inside. If you know that the weather affects your COPD, don’t go outside when conditions aren’t suitable. Stay inside your home with a fan to keep you comfortable during humid days.

Protect your lungs in cold weather. If the weather is cold, cover your nose and mouth loosely with a scarf before you go outside. This will help warm the air before it goes into your lungs. Breathe in through your nose and out through your mouth.