1 The largest school district by enrollment with an election in 2016 is Wake County Public School System with 153,534 K-12 students.  The smallest North Carolina school district among the nation's largest with an election in 2016 is Duplin County Schools with 9,628 K-12 students.
Freon only remains a liquid while under pressure inside your refrigerator's cooling system. The chemical changes to a gas as soon as it contacts the air. This means, when you smell freon in and around your refrigerator, you're also inhaling varying amounts of freon gas. According to the Environmental Protection Agency, freon gas is denser than air and travels very slowly to the upper atmosphere.
It's water vapor, which is a gas that is lighter than nitrogen or oxygen. (Related: Understanding water in the atmosphere). Compared to the differences made by temperature and air pressure, humidity has a small effect on the air's density.But, humid air is lighter than dry air at the same temperature and pressure.s air pressure decreases oxygen continues to account for about 21% of the gasses in the air as it does at sea level. But, there is less oxygen because there is less of all of the air's gasses. For instance, by the time you go to 12,000 feet the air's pressure is about 40% lower than at sea level.