A parking structure that, at each parking level, has wall openings open to the atmosphere, for an area of not less than 1. 4 ft2 for each linear foot (0. 4 m2 for each linear meter) of its exterior perimeter. Such openings are distributed over 40 percent of the building perimeter or uniformly over two opposing sides. Interior wall lines and column lines are at least 20 percent open, with openings distributed to provide ventilation.