A population study of children born in a city in Canada found that air pollution exposure during pregnancy could cause childhood asthma
Right now, air quality is killing people. In London, pollution was legally ruled a factor in the death of Ella Kissi-Debrah, a young schoolgirl with severe asthma. The coroner said: “The whole of Ella’s life was lived in close proximity to highly polluting roads. I have no difficulty in concluding that her personal exposure to nitrogen dioxide and PM was very high.”
What about other cities across the world?
While cities occupy 3% of the Earth, they are home to 50% of the global population. A separate study looked at how not enough climate change calculations take cities into account.
In another study, researchers found that childhood pollution exposure could lead to cognitive deficiencies – up to 60 years in the future.
Now, researchers at Lawson Health Research Institute and Western University, have results from a population study that focuses on air pollution exposure. They say that children born in Sarnia, a city in Ontario, have a higher risk of developing asthma than those in neighbouring cities.
The researchers followed 114,427 children born in Sarnia, Windsor and London between 1993 and 2009 for 10 years.
Sarnia is home to the ‘Chemical Valley’
“It’s known that cities in Southwestern Ontario have varied levels of air pollution because of differences in industry and traffic. For example, Sarnia is home to the ‘Chemical Valley’ where numerous chemical plants and oil refineries are clustered,” Dr Dhenuka Radhakrishnan, an Adjunct ICES Scientist, formerly working out of ICES Western in London, and Pediatric Respirologist at CHEO, commented.
“We wanted to see if children born in three cities – London, Windsor and Sarnia – had a different risk of developing asthma due to the differing air pollution levels in the three regions, even though the people living in these cities are otherwise comparable in many ways.”
Unsurprisingly, the team found that children in Sarnia were at the highest risk of developing asthma.
By 10 years old, 24% of children in Sarnia have asthma
The researchers found that by the age of 10, nearly 24% of children in Sarnia were diagnosed with asthma, compared to 21% in Windsor and 17% in London.
The differences could not be explained away by the many risk factors associated with asthma, such as sex, socioeconomic status and urban versus rural setting. The findings were most striking in the first two years of life, but continued beyond the age of six.
Exposure during pregnancy can influence asthma
“It’s important to find strategies to prevent asthma development and this study suggests that reducing air pollution exposure, including environmental causes, might reduce the number of children who suffer from asthma,” said Dr. Salimah Shariff, Associate Scientist at Lawson, Adjunct Professor at Western and Scientist at ICES Western.
“We need to carefully examine how reducing air pollution exposures within a geographic area translates to reductions in asthma development. Understanding the amount of air pollution that a mother and infant are exposed to, and how this impacts their personal risk, could enable regions to target safer levels for their residents.”