 Chemical Valley and the surrounding area are home to 62 facilities and refineries . These industrial complexes are the heart of Sarnia 's infrastructure and economy . They directly employ nearly 8 @,@ 000 , and contribute to almost 45 @,@ 000 additional jobs in the area . In 1971 , the Canadian government deemed this area so important to the economic development of the country that it printed an image of a Sarnia Oil <unk> on the reverse of the Canadian $ 10 note . The huge industrial area is the cause of significant air and water pollution . The Canada Wide Daily Standard for airborne particulate matter and <unk> pollution , regulation <unk> , is 30 <unk> per cubic metre . Forty @-@ five percent of this particulate air pollution in Sarnia comes from Chemical Valley , and the rest drifts over the St. Clair River from the neighbouring United States in the form of what is known as " <unk> Air <unk> . " 
