Mold and mildew in household air can definitely cause asthma problems because the particles they give off irritate the lungs. Some asthmatics are allergic to mold and mildew. Repeated exposure can cause asthma to worsen. (Sometimes, they’re the main cause of asthmatic symptoms). Asthmatics may experience mild to dramatic improvements after cleaning their homes if they have a lot of mold and mildew. Doctors can often help estimate how much improvement patients might expect.
Mold and mildew are not likely to be the main cause of pneumonia because they do not contain the bacteria that cause most cases of pneumonia. Some cases are caused by Legionella, a particular bacteria that likes to grow in moist conditions. Outbreaks of pneumonia have been traced back to central air-conditioning systems that were contaminated with Legionella.
Bronchitis is unlikely to be caused by mold and mildew; it’s usually caused by viruses and bacteria.
Even healthy people may experience respiratory problems in houses contaminated with too much mold and mildew. If you’re having these problems, try keeping your house really clean for 6 months and see if your condition improves.