Background Paragraph: Regions on the Earth's surface (or in its atmosphere) that are high above mean sea level are referred to as high altitude. High altitude is sometimes defined to begin at 2,400 meters (8,000 ft) above sea level.[5][6][7]

At high altitude, atmospheric pressure is lower than that at sea level. This is due to two competing physical effects: gravity, which causes the air to be as close as possible to the ground; and the heat content of the air, which causes the molecules to bounce off each other and expand.[8]. 
Story: Riley has just been diagnosed with a disease that requires him to be in an area that has low atmospheric pressure to help his breathing. He has two cities he can choose to live in based on his current budget. Denver with an elevation of 10,000 ft, and Miami, which is around sea level. 
Question: Will Denver or Miami have a higher atmospheric pressure?
Miami.