Residents of the U.S.-Mexican border metropolis of El Paso-Ciudad Juárez have taken heart in recent years as serious air-quality problems have shown signs of easing. Statistics compiled both by the Autonomous University of Ciudad Juárez and the Texas Commission on Environmental Quality indicate that since the early and mid-1990s, instances in which ozone, carbon monoxide and particulate levels exceed U.S. and Mexican standards have occurred less frequently. Experts attribute the improvement to a variety of factors. Among them: use of more efficient cars and trucks, the Mexican oil company Pemex’s decision to sell oxygenated fuel in winter months, the paving of some of Juárez’s dirt roads and the closure of the Asarco smelter in El Paso, whose smokestack emissions blackened the... [Log in to read more]