Every fall, when the barometer drops, Mary Middlemiss has trouble breathing.

After experiencing shortness of breath and recurring lung infections about 15 years ago, the Ottawa resident was diagnosed with chronic obstructive pulmonary disease (COPD).

Middlemiss is one of about 1.5 million Canadians who suffer from COPD, which, despite being the fourth biggest killer of Canadians, isn’t as well known as it should be.

And today, COPD World Day, Middlemiss wants to raise awareness of the disease.

“Not many people know someone that has COPD because it’s under the radar,” said Dr. Rick Hodder, a respirologist with the Ottawa Hospital at the University of Ottawa. “But ... by teaching people to deal with the disease, they can improve their quality of life.”