Is 90% of air pollution caused by 25% of cars?

A study conducted at the University of Toronto in Canada indicates that yes, the majority of automotive pollutants are coming from a very small number of vehicles and the result is premature deaths from breathing the harmful substances.

To examine the emissions of 100,000 vehicles, the researchers used a technique that was capable of taking immediate readings. They set the equipment up on College Street in Toronto and monitored the results. The analysis found that just 25 percent of the cars tested created 95 percent of the total soot and 93 percent of the carbon monoxide.

“As we looked at the exhaust coming out of individual vehicles, we saw so many variations. How you drive, hard acceleration, age of the vehicle, how the car is maintained – these are things we can influence that can all have an effect on pollution,” author Greg Evans said in the university’s announcement of the results.

In a separate study, Evans and his team used a mobile lab to take real-time emissions readings. While air quality is known to be poor even up to 270 yards away from major roads, the researchers found that pollutants can still be double their normal levels over 300 yards away for those downwind of a highway. People living around multiple high-traffic areas can experience even higher levels.

While both studies focus on emissions only within small geographic areas, they indicate that there’s still a lot to be done to lower air pollution from vehicles.

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