Pedestrians walking along Carling Avenue near the Queensway suck in some of Ottawa's most polluted air, according to early findings of the City of Ottawa's air-pollution mapping project.

The area has the worst air quality so far among 34 locations where airborne contaminants are beingmeasured, said Natividad Urquizo, who runs the city's air pollution program.

'I'm borderline asthmatic and I would think twice before buying a house in that area.'—Natividad Urquizo, City of Ottawa

The soup of pollutants hanging above the roadway includes levels of nitrous oxides and particulate matter that are often above recommended safe levels, and both types can cause serious health effects, Urquizo said.

"I'm borderline asthmatic and I would think twice before buying a house in that area," she added.

The pollution map,which could be produced by as early as next month,will help the city decide where to put facilities such as new schools and seniors homes, Urquizo said.

She added that not all pollutants are concentrated in the city's centre.

For example, ozone, which protects against UV light when it is high in the atmosphere, but is toxic at ground level, has a distribution people might not expect.

"It has been discovered that [ground-level] ozone is lower in the downtown core, but it's higher in the rural areas," she said.

Exposure to ozone, the main component in smog, has been linked toinflammatory lungdisease and death, particularly among people with chronic lung disease, and has also recently been shown to kill human immune cells.

The 15-month National Capital Air Quality Mapping project was launched in June. To take air pollution measurements, the project employing a satellite monitoring system, twomonitoring systems on the ground,three mobile testing units and 100 small sensors placed on buildings and streetlight poles.The map will show levels of various pollutants in each square kilometre of the city.

The studying is being funded by the City of Ottawa, Natural Resources Canada's GeoConnections program, Environment Canada, Transport Canada, the Ontario Ministry of the Environment and the Ottawa International Airport.