The following map of the atmospheric corrosivity measured in Central America was adapted from "Atmospheric Corrosion of Copper in Ibero-America" by M. Morcillo, E. Almeida, M. Marrocos, and B. Rosales, Corrosion, Vol. 57, No. 11, pages 967-980.
Like much of Latin America, Central America's urban centers experienced large population growth throughout the 1990s. This growth has in most cases resulted in an increase in the number of motor vehicles, thus leading to the growing problem of urban air pollution. In the countries of Central America, the number of motor vehicles on roads has increased up to 16% each year. For example, the number of vehicles in El Salvador has doubled since 1990 (there are now 500,000 automobiles, for instance). It is estimated that nearly 70% of all urban air pollution in the Central American region is caused by vehicular traffic. The chief polluters have traditionally been poorly maintained trucks and buses which run on lower quality fuels, such as leaded gasoline. However, the majority of countries in Central America have recently phased out the use of leaded gasoline, with Panama being the region's only nation to still permit the use of leaded gasoline for transportation. Panama plans to ban the sale of leaded gasoline by 2002.
Costa Rica is a leader regarding air quality in Central America. In 1996, it banned the use of leaded gas and has since reduced its ambient lead levels by two-thirds. Furthermore, every motor vehicle in Costa Rica must now pass an annual emissions inspection, and imported cars must come equipped with catalytic converters. Although much remains to be done regarding the process of improving the air quality of Central American cities, the region's countries appear to be making positive strides. (reference)
Other regions and countries: Argentina, Brazil, Canada, Central America, Chile, China, Colombia, Cuba, France, Germany, India, Italy, Japan, Mexico, New Zealand, North America, Portugal, Russia, Saudi Arabia, South Africa, Spain, Sweden, UK, USA, Venezuela