Higher levels of toxic air pollutants are being released into the air through tar sands in Canada's Alberta Province than previously believed, according a University of Toronto Scarborough study. Researchers said that official records fail to mention the emission levels of carcinogenic pollutants known as polycyclic aromatic hydrocarbons (PAHs).

"When dealing with chemicals that have such great potential to harm people and animals, it is absolutely vital that we truly understand how, and how much they are being released into the environment," Abha Parajulee, the lead author of the paper, said in a press release.

PAHs are generated when the petroleum is extracted from the tar sands. Besides cancer, PAHs are known to cause asthma and lower IQs in children born to mothers exposed to these pollutants.

Previous studies conducted on the same subject showed that PAHs are emitted into the environment from tar sands at reasonable levels.

The current study found that there are indirect pathways through which PAHs can enter the air. For examples tailing ponds that are created through oil extraction are more likely to release more PAHs into the atmosphere than direct means. Plus, the pollutants escape into the air while transporting and storing other waste materials from oil sands operations.

"Tailing ponds are not the end of the journey for the pollutants they contain. PAHs are highly volatile, meaning they escape into the air much more than many people think," Parajulee said.

"We need to take a holistic approach that includes both modeling and monitoring. This is the single most powerful way to inform public policy and private management strategies for the region," Frank Wania, a professor of environmental chemistry, said.

The finding has been published in the journal Proceedings of the National Academy of Science.