2. Mouth breathing can trigger asthma: Your nose humidifies inspired air, so if you breathe through your mouth, this air is not getting humidified enough. This is especially important during the winter months when the air is drier. Studies have linked nasal congestion with severe asthma, and I think this is one of the main reasons -- those with sinus trouble breathe through their mouths.
3. Cold air triggers asthma: Again, this is true because the colder the air, the less humid the air is. This is why asthmatics, especially those with exercise-induced asthma, have trouble exercising outside when the air is cold. Rapid breathing of cold, dry air triggers asthma.
To prevent asthma, the The Centers for Disease Control and Prevention recommends humidity be set between 35 percent and 50 percent. Humidifiers can be used in the winter months, and air conditioners and dehumidifiers in the summer months.
It's good wisdom to know that cold air, dry air, and humid air can trigger asthma. It's also important to know that by working with your doctor to control your asthma, you should still be able to continue doing the things you love most.