1) I don't know if there could be a possibility to build a car using *directly* the nitrogen from the earth atmosphere, but there are already cars using liquid nitrogen, which has already been produced for years. It can be extracted from the earth atmosphere. 2) "Researchers at the University of Washington are developing a new zero-emission automobile propulsion concept that uses liquid nitrogen as the fuel." "Due to lack of funding, this research project at the UW is no longer active." http://www.aa.washington.edu/AERP/CRYOCAR/CryoCar.htm Further information: http://www.washington.edu/alumni/columns/dec97/car4.html "A Car Powered by Liquid Nitrogen!" http://www.mtsc.unt.edu/CooLN2Car.html 3) "In the past, I’ve discussed some of the major threats to hydrogen cars in the future car marketplace. Such threats include electric vehicles, biofuel vehicles, solar cars and compressed air vehicles. And, liquid nitrogen (LN2) cars must also be added to the list. The air we breathe is made up of 78-percent nitrogen, 21-percent oxygen and 1-percent of other gases. This means that if liquid nitrogen is used for fuel and released back into the environment, it also becomes a zero emissions alternative." Source: http://www.hydrogencarsnow.com/blog2/index.php/competition/liquid-nitrogen-car-threatens-hydrogen-car/ 4) "Liquid nitrogen (LN2) is a method of storing energy. Energy is used to liquify air, and then LN2 is produced by evaporation, and distributed. LN2 is exposed to ambient heat in the car and the resulting nitrogen gas can be used to power a piston or turbine engine. The maximum amount of energy that can be extracted from 1 kg of LN2 is 213 W-hr or 173 W-hr per liter, in which a maximum of 70 W-hr can be utilized with an isothermal expansion process. Such a vehicle can achieve ranges similar to that of gasoline with a 350 liter (90 gallon) tank. Theoretical future engines, using cascading topping cycles, can improve this to around 110 W-hr/kg with a quasi-isothermal expansion process. The advantages are zero harmful emissions and superior energy densities than compressed air, and a car powered by LN2 can be refilled in a matter of minutes." Source: http://en.wikipedia.org/wiki/Alternative_fuel_vehicle#Liquid_Nitrogen_car Further information: http://en.wikipedia.org/wiki/Liquid_Nitrogen_Economy http://en.wikipedia.org/wiki/Liquid_nitrogen