Pulmonary edema occurs when the alveoli fill up with excess fluid seeped out of the blood vessels in the lung instead of air. This can cause problems with the exchange of gas (oxygen and carbon dioxide), resulting in breathing difficulty and poor oxygenation of blood.
Currently buildings are limited to a height of 200 meters and are subject to not contrasting the view of Mount Royal, the city's central green space, with the only exception being antennas and communication towers, that are allowed to reach 223 metres (732 ft) above mean sea level.
A skyscraper is a continuously habitable high-rise building that has over 40 or 50 floors and is taller than approximately 100 m. Historically, the term first referred to buildings with 10 to 20 floors in 1880s. The definition shifted with advancing construction technology during the 20th Century. Skyscrapers may contain offices, commercial and residential uses. For buildings above a height of 300 m, the term supertall can be used, while skyscrapers reaching beyond 600 m are classified as meg