Air quality standards are emission rates or concentrations or deposition rates that are designed to protect people and the environment from harm. The Earth’s atmosphere is one of the global commons – those regions, which also include Antarctica, the ocean floor and outer space, over which no one nation has individual control. There is clear distinction between airspace, which is the 3D volume extending from the surface of a nation up to the top of the atmosphere, and the air that flows through it. Although each nation has sole responsibility for its own airspace, it has joint responsibility for the air within it.