In the recent years, breathing harmful substances from the air has become one of the leading causes of premature deaths. Although, most of the modern cars are equipped with technologies that help lowering emissions, yet a recent study suggests 90 percent of pollution from the vehicles come from only a quarter of the cars.

The study conducted by the researchers at University Of Toronto was published in the March 2015 edition of Atmospheric Measurement Techniques. The Author Greg Evans said that a lot of things were taken into account when monitoring the emissions such as how roughly a vehicle is driven, acceleration of the vehicle, the model year and the condition of the car.

The research revealed that the major harmful pollutants, 95 percent black carbon (soot), 93 percent of carbon monoxide, and 76 percent of volatile organic chemicals (like benzene, toluene, ethylbenzene, and xylenes) were emitted by just 25 percent of the vehicles on the road.