E-mail A Friend Tell a friend about the information found on this page by sending them an e-mail.   Your Name: Your E-mail:   Type an e-mail address, then click add: Add a Personal Message: (Optional)

April 2008 issue	In this issue Table of Contents Feature: Polar vision Feature: Carbon cemetery Feature: North Shore highway The Inside Story Editor's Notebook Reverberations Explorer À la carte Mosaic

Click map to enlarge

Smog signals
Burn fossil fuels, and you get nitrogen dioxide, a nasty pollutant that’s fouling the air around the globe
By Steven Fick and Elizabeth Shilts

It may look pretty, but this global view reveals one ugly problem. Researchers at the Royal Netherlands Meteorological Institute have pinpointed hot spots of nitrogen dioxide (NO₂) pollution in the troposphere, the air we breathe.

Traffic, power plants, heavy industry and oil refineries are the biggest emitters of NO₂, a gas created when fossil fuels are burned, so it’s not surprising that the skies over much of the world’s emerging industrial powerhouse, China, are now clouded with the pollutant. Emissions of NO₂ in Shanghai, one of the fastest-growing cities in the world, have increased by 29 percent a year since 1996. It ranks with Los Angeles and Mexico City as the urban areas with the highest NO₂ concentrations in the world.

An extremely reactive gas, NO₂ combines with tiny particles in the air to create the reddish brown smog that hangs over larger cities in the summer and plays a role in the production of ground-level ozone, both of which have been blamed for a host of respiratory problems. The World Health Organization has estimated that such air pollution reduces the life of the average European by 8.6 months.

NO₂ emitted by oil sands plants in Fort McMurray, Alta., and refineries east of Edmonton leaves smudges on the map, as does NO₂ from individual power plants in Chandrapur and Ramagundam in India and oil refineries around the Persian Gulf. The bright red blight in South Africa is centred in the Highveld area outside Johannesburg, where a number of power plants sit on a plateau. High altitude lengthens the lifespan of NO₂ in the air.

Cleaner technology in cars and power plants in Europe and eastern North America has led to declines in NO₂ in those regions over the past decade, but huge increases in emissions in East Asia mean the air will remain hazy and hazardous for millions of people for years to come.

top