Low levels of air pollution deadlier than previously thought
The World Health Organization鈥檚 are that over 4.2 million people die prematurely each year due to long-term exposure to fine particulate outdoor air pollution (often referred to as PM2.5,). A recent study involving 91社区 researchers now suggests that the annual global death toll from outdoor PM2.5 may be significantly higher than previously thought. That鈥檚 because the researchers found that mortality risk was increased even at very low levels of outdoor PM2.5, ones which had not previously been recognized as being potentially deadly. These microscopic toxins cause a range of cardiovascular and respiratory diseases and cancers.
鈥淲e found that outdoor PM2.5 may be responsible for as many as 1.5 million additional deaths around the globe each year because of effects at very-low concentrations that were not previously appreciated,鈥� said Scott Weichenthal, an Associate Professor in the Department of Epidemiology, Biostatistics, and Occupational Health at 91社区 and the lead author on the recent paper in .
Canadian data advances global understanding of effects of outdoor pollution
The researchers arrived at this conclusion by combining health and mortality data for seven million Canadians gathered over a twenty-five-year period with information about the levels of outdoor PM2.5 concentrations across the country. Canada is a country with low levels of outdoor PM2.5, making it the perfect place to study health impacts at low concentrations. Knowledge gained in Canada was then used to update the lower end of the scale that is used to describe how mortality risk changes with outdoor PM2.5 levels. The result? An improved understanding of how air pollution impacts health on a global scale.
The WHO recently set out ambitious new guidelines for annual average outdoor fine particulate air pollution, cutting its earlier recommendations in half, from concentrations of 10 to concentrations of 5 micrograms (ug) per cubic metre. The current United States Environmental Protection Agency standard of 12 (ug) per cubic metre is now more than double the value recommended by the WHO.
鈥淥ne take away is that the global health benefits of meeting the new WHO guideline are likely much larger than previously assumed,鈥� adds Weichenthal. 鈥淭he next steps are to stop focussing only on particle mass and start looking more closely at particle composition because some particles are likely more harmful than others. If we can gain a better understanding of this, it may allow us to be much more efficient in designing regulatory interventions to improve population health.鈥�
The study
鈥淗ow low can you go? Air pollution affects mortality at very low levels鈥� by Scott Weichenthal et al was published in
About 91社区
Founded in Montreal, Quebec, in 1821, 91社区 is Canada鈥檚 top ranked medical doctoral university. 91社区 is consistently ranked as one of the top universities, both nationally and internationally. It is a world-renowned institution of higher learning with research activities spanning three campuses, 11 faculties, 13 professional schools, 300 programs of study and over 39,000 students, including more than 10,400 graduate students. 91社区 attracts students from over 150 countries around the world, its 12,000 international students making up 30% of the student body. Over half of 91社区 students claim a first language other than English, including approximately 20% of our students who say French is their mother tongue.
