The five million inhabitants of Santiago, Chile are exposed to high levels of air pollution
during a significant portion of the year. Santiago ranks as one of the most polluted cities
in the world and freequently confronts air-quality alerts and pollution emergencies. Air pollution
in Santiago results in damaging respiratory diseases and a large number of premature deaths.
Located in central Chile, the city sits in the middle of a valley and is surounded by two
mountain ranges: the Andes mountains and the Cordillera de la Costa. Because of Santiago's
unique geographic location and weather patterns, ventilation and dispersion of air pollutants
within the valley are restricted;thus explaining why Santiago, with emission levels similar to
those in other cities, suffers from such high atmospheric pollution levels. The pollution problem is further exacerbated in winter
when wind and rainfall levels are at their seasonal lowest.
Besides geography and weather, air pollution in Santiago is a result of both mobile and fixed sources, a growing economy, rapid urban
expansion and an increasing rate of automobile use. Although the city has a state-run underground
metro system, cars and trucks are becoming increasingly more popular as the number of private
automobiles in Santiago has climbed to nearly 1 million. This trend is a significant threat towards
the improvement of Santiago's infrastructure problems while simultaneously clamping down on
automobile usage, a politically difficult situation.
Further contributing to Santiago's air pollution problems are emissions from nearby factories. As recently as July 5, 2000
more than 250,000 motor vehicles were ordered to stay off Santiago' roads, and nearly 2,500
polluting industries were temporarily shut down, as a result of the worst smog emergency of the year.
As Chile is the world's largest producer of copper, industrial emissions in Santiago primarily arise
from the mining sector and smelter operations. The process of mining contributes a considerable amount of pollutants to both the air and water;
chief pollutants include sulfur dioxide, arsenci and suspended particulate matter. High atmospheric levels of particulates smaller than
10 microns (considered to be the most harmful) also are a result of street dust blown in from the unpaved roads of Santiago's
impoverished suburban slums. The World Bank has estimated that a given reduction in particulate matter smaller than 10
microns would produce health benefits 10 times greater than similar reductions in all other pollutants combined.
In 1997, Santiago and Chicago signed a Memorandum of Understanding under the U.S Department of Energy's Clean Cities program as "Sister Cities," whereby Chile agreed to implement a $1.2 million subsidy for the deployment of a fleet of natural gas buses. More recently, in an effort to dramatically improve the air quality of Santiago, President Lagos and his government released the Santiago Metropolitan Region anti-pollution plan. The five-year framework plan aims to establish specific goals for the reduction of vehicle and industrial emissions, particulate matter and the improvement of ventilation corridors within the city. Although previous governments had participation in green programs and expectations for environmental improvements now aer at an all-time high. President Lagos also has proposed plans for paving the streetrs of Santiago's suburbs as well as an incentive program to relocate industries to other regions of the country.