Pollution is highly localized: take the back streets

Sure, the big city is worse than the country for air quality. But air pollution is more complicated than city = bad, country = good.

Air pollution, it turns out, is highly localized, so the back streets in a big city are significantly less polluted than busy streets in the same city. If there is a traffic jam, exposure to air pollutants varies depending on whether you’re walking on one side of the road or the other. Location matters enough that small children closer to the height of car exhausts will inhale more toxins than adults who stand taller.

So, if you’re not about to move to the country, you could still help yourself and your family by taking the back streets.

I first read about this in a BBC Science Focus article, but see, for example, Varaden, D., Leidland, E., Lim, S., & Barratt, B. (2021). "I am an air quality scientist"- Using citizen science to characterise school children's exposure to air pollution. Environmental research, 201, 111536.

"We identified that, on average, children were exposed to higher levels of air pollution when travelling to and from school, particularly during the morning journey where air pollution levels were on average 52% higher than exposures at school. Children who walked to and from school through busy main roads were exposed to 33% higher levels of air pollution than those who travelled through back streets."

I updated this from the original for my book Big Ideas Little Pictures