The leakage of unburned liquefied petroleum gas (LPG) is a major source of
urban nonmethane hydrocarbons (NMHCs) in the air of Santiago, Chile. Roughl
y 5% of the LPG that is sold in Santiago leaks in its unburned form to the
atmosphere. Because of the leakage, propane is the most abundant NMHC in Sa
ntiago's air, even under heavy traffic conditions. NMHCs are an important p
recursor to the formation of ground-level ozone, and the LPG leakage may co
ntribute as much as 15% to the excess ozone levels in Santiago. Improvement
to the local air quality may be obtained by lowering the rates of LPG leak
age, and by minimizing the use of alkene-rich LPG formulations.