Air pollution

Higher density equals more walking. “This is an issue of life and death.” But a new Canadian study finds that air pollution can offset these benefits. One of the authors of the study, Nicholas Howell, is interview for St. Michael’s Hospital, where the research was done. Sprawl, in effect, kills. Less density equals more driving. “We are engineering exercise out of people’s lives” by creating suburban cul-de-sacs; and putting places of work and living far from each other.

Previous research has shown that people living in walk able neighborhoods tend to be more active; are less likely to be overweight or obese, and are less likely to develop health conditions like high blood pressure or diabetes. This is great news and a positive finding for public health and urban design; but our team wondered how we square these results with our day-to-day experiences.

Air pollution in urban areas

Does the congestion and air pollution offset some of these benefits? The researchers used statistical models to predict nitrogen oxide levels in various locations across the Province of Ontario, and linked this to individual’s home addresses. Critically, we further found that while residing in an unworkable neighborhood was associate with a higher likelihood of having diabetes or hypertension than living in the most walk able communities; any observe benefit for those living in walk able areas appear to be lost in the most polluted areas.

The researchers come up with recommendations that would make urbanologists happy; starting with reducing the amount of traffic, building bike lanes to encourage cycling, enhancing public transit; and adding more inter-city train service. “This last idea is particularly important because other research has found that much of the air pollution in urban areas; might be generated by people driving into those areas rather than the residents themselves.”

This is not the first study that has pointed out the dangers of air pollution; I wrote earlier about a study in the UK that concluded that the benefits of walking were negated by high levels of NO2 and particulates; particularly for older people. It also conclude that “it is important to impose policies and measures that can reduce traffic pollution; so that every individual can enjoy the health benefits of physical activity.”

Walking and cycling more attractive options

In the Toronto Star, Jacob Lorinc and Emma Sandri quote Dylan Reid of advocacy group Walk Toronto, who says this shouldn’t discourage people from walking. “The federal government needs to make the regulations that are necessary; whether it’s through a carbon tax or vehicle emissions standards, to reduce air pollution, while the province and city need to create public transit; that offers a plausible alternative to driving and make walking and cycling more attractive options.“It’s really important, when you look at a study like this, to see that the solution is a long-term solution that gets more people walking and cycling, more people taking transit, and reducing the amount of cars used.”

Exactly. We need fewer and cleaner cars and trucks, more and safer alternatives like better walking, biking and transit infrastructure. We might rethink the logic of putting highways on waterfronts or in beautiful green valleys; as they did in Toronto. And as one professor noted after the UK study: “It’s important to that people continue to exercise. In the U.K., physical inactivity is the fourth largest cause of disease and mortality and contributes to around 37,000 premature deaths in England every year.” Start by finding a cleaner, greener place to do it.