Greg Greenslade never imagined life would bring him alongside hundreds of people, climbing a 48-storey building in support of those struggling with lung conditions.

More than three years ago, he was one of those patients.

Greenslade suffered from pulmonary fibrosis, a disease that results in scarring of the lungs which makes it hard to take in deep breaths. There are no cures.

His doctor told him he only had one month to live but on July 4, 2015, a pair of lungs was available, giving him a new lease on life.

"Without the transplant, I wouldn't be here," he said. "You don't take nothing for granted."

Greenslade said without the donor’s life-changing gift, he wouldn't have been able to walk his two daughters down the aisle on their wedding days.

On Sunday, he participated in the 18th Annual Climb the Wall at the Sheraton Wall Centre in support of the BC Lung Association.

He said he wanted to give back to the community and inspire hope.

"I want to say thank you, but thank you doesn’t seem like enough. That's why we do this, to give somebody something to see."

Many firefighters from various departments in the Lower Mainland also geared up for the challenge. 

“For many faced with breathing problems, climbing just one flight of stairs is difficult. No one understands this better than firefighters who in the line of duty are called upon to navigate their way up stairs and through smoky buildings at a moment’s notice,”said Chris Lam, CEO of the BC Lung Association.

Over the past 18 years, the event raised more than $1.6 million for lung health research, education and patient support programs.

With files from CTV Vancouver's Julie Nolin