Geography Reference
In-Depth Information
FIGURE 10.8 The paradox of continuing domestic fuelwood use in a time of mobile phones, other elec-
tronic technologies, and modern construction, Yulongxue Shan, Hengduan Mountains, Yunnan,
China. (Photo by J. S. Gardner.)
Reduced atmospheric oxygen pressures affect other relevant aspects of human life
at high altitudes, particularly the processes or devices that rely on combustion. Cook-
ing food, heating homes, and operation of vehicles and other machinery are affected. As
oxygen is reduced with the gain in altitude, combustion is less complete, producing less
heat and more carbon monoxide. As less energy is imparted to cooking, heating, and
powering machinery from a given amount of fuel, more fuel and time are required than
at lower altitudes. This translates directly and indirectly into greater costs and greater
environmental impacts (Fig. 10.8). Increasing air intake helps address this problem in
vehicles and aircraft, but only to a point. Fixed-wing aircraft and helicopters with some
adjustments can operate at altitudes above 4,500 m. Aircraft using jet or turbojet en-
gines are not so affected by the problem of oxygen depletion. It is not uncommon now
for military and civilian helicopters to operate at altitudes well above 6,000 m.
In the mountain villages, everyday tasks like cooking and heating are compromised
by reduced air/oxygen pressure. In cooking, the problem is more complex than reduced
combustion and energy transfer. Three complexities are involved: the increased expan-
sion of leavening gases, the lowered boiling point of water, and the increased evapora-
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