City of Denver dramatically cuts air pollution

In the late 1970s, Denver used to exceed federal air pollution standards for 200 days per year every year, but in the last five years, there has been a total of only 15 days on which violations have occurred, an Environmental Protection Agency (EPA) spokesman told edie. This remarkable change around has happened for a number of reasons.

Firstly, emissions from vehicles, which still produce 60 to 70% of pollution, have been cut by 80%, through both the use of cleaner cars, and cleaner fuels, with drivers having their vehicles inspected every two years to ensure that they comply with rules on clean burning engines. Denver was also the first city in the state to require motorists to use oxygenated fuel in the winter, cutting down on carbon monoxide pollution. “The catalytic converters on vehicles are also much better than they used to be,” explained the EPA spokesman, adding that car pooling schemes and public transport have also been increased.

In the past, the city’s troubles have been added to by temperature inversions resulting from Denver’s geographical location where layers of warm air are held down by heavier cool air, causing pollution to stagnate, the situation only being rectified by moisture or wind. Now on such ‘high pollution’ days, wood burning has been banned, reducing the pollution threat.

On top of this, the city’s largest energy provider has also been persuaded to reduce emissions, and has converted its main power station from coal to natural gas.

Finally, sand and gravel used to be put down on Denver’s roads following a heavy snowstorm. This would then be pulverised into dust by passing vehicles and form a notorious brown cloud that caused lung problems. The sand and gravel is now mixed with salt or an environmentally benign de-icing chemical, and is cleaned up after 24 hours.

Denver’s new clean air is good for the city’s image; it’s good for attracting tourists; and it’s good for the health of residents and visitors, said the EPA spokesman. As for Denver’s previous image as a dirty city, “that stigma has now been removed”, he said.