Maybe the street-sweeping truck in your town is there simply to make the streets tidier.
But in Santiago, 25 new vacuum trucks that began sucking up street dust May 1 have a more serious job to do. They're assigned the task of reducing this sprawling city's serious particulate pollution levels by one-quarter over the next five years.
That's a lot of dust.
At an annual operating cost of about $2 million, the trucks will prowl Santiago's principal arteries for 7-1/2 hours every night with the goal of ingesting 4,500 tons of dust every year.
Santiago is known in Latin America for its air pollution. Like Mexico City, car owners are not allowed to drive their car one day of the work week, in an effort to reduce auto emissions. (Cars with catalytic converters receive a special dispensation.) This week, 80 percent of the capital's cars were grounded in an effort to control pollution, which had reached emergency levels.
But then there's dust. According to government studies, dust represents about 80 percent of airborne particulates Santiagans are susceptible to breathe. Much of it is sent aloft by cars and trucks whizzing along the city's avenues. And that dust contains dangerous amounts of lead, chrome, copper, and other heavy metals.
Other elements of the dust-reduction program are a reforestation program and paving the city's hundreds of miles of unpaved streets in poorer, peripheral communities.
If the plan works, residents of the capital should be able to enjoy clearer views of the snow-capped Andes that frame the city. And they should be able to breathe a little easier.