The troposphere contains 75 percent of atmosphere's mass-on an average day the weight of the molecules in the air is14.7 lb..(sq. in.)- and most of the atmosphere's water vapor.ater vapor plays a major role in regulating air temperature because it absorbs solar energy and thermal radiation from the planet's surface. The troposphere contains 99% of the water vapor in the atmosphere. Water vapor concentrations vary with latitudinal position(north to south).
Proper is different from typical or average. Average mantel height is about 54 above the hearth extension. Proper depends on the fireplace size, required clearances and the aesthetic desired, which can vary widely. These are both proper mantel heights: This one's about 48 high.
1 A higher end mantel, such as a marble fireplace mantel that has a traditional Italian design, can cost anywhere from $9,000 to $11,500. 2  Customized mantels can be in this price range as well if you choose to purchase a mantel that has a higher end stone such as marble.he price of mantels greatly varies depending on the design as well as the size of the mantel itself. 1  On average, a fireplace mantel can cost $300 to as much as $11,500 or more. 2  A higher end mantel, such as a marble fireplace mantel that has a traditional Italian design, can cost anywhere from $9,000 to $11,500.