To clean our air we have to stop pollution at the source

Cheonggyecheon River
CC BY 2.0 This used to be a highway/ rNux on Flickr

Filters on buses and smog-eating towers are not the answer.

It seems like only yesterday that I was complaining about parents in London crowdfunding to raise money to build a living wall. They want to build it to suck up pollution, but instead they should be dealing with the source of the problem, which is far bigger than their living wall can begin to cope with. Or, as Gary Fuller writes in the Guardian, we need to "forget ‘solutions’ such as smog towers, air-filtering buses and pollution-eating paints" (and I might add living walls).

Ideas such as these that try to clean the air rather than fix the problem may be politically achievable, but they founder on a point of physics: there is simply too much air to clean. Remarking on the towering filters being installed alongside junctions in Delhi, York University’s Ally Lewis, professor of atmospheric chemistry, likened filtering outdoor air to “trying to air-condition a room with the roof off”. It is far better to prevent the air pollution in the first place.

Fuller has just published a book, The Invisible Killer: The Rising Global Threat of Air Pollution - and How We Can Fight Back and has a series of suggestions for dealing with the source of the problem that are straightforward, obvious and will probably never happen, because of politics. The Guardian article, "What would a smog-free city look like?", summarizes:

1. An end to gas and diesel. (But electric cars are still a problem)
2. Turning roads into parks (removing highways)
3. The right transport (Bikes!)
4. Heating our homes (with gas instead of solid fuels)
5. Business must pitch in (get rid of diesel)
6. Neighbours need to help (pollutants don't respect borders)

The great thing about this article is that it is a constructive list of things that can be done, all of which remove pollution at the source instead of trying to suck it out of the air. The not so great thing is that almost all of the points made rely on drastically reducing the number of cars we have on the road, something that is still politically unpalatable.

In the end, it is wonderful that everyone is thinking about air quality and what they are breathing, but the most problematic pollutant coming out of cars and gas-burning houses is carbon dioxide, and there is no filter for that.

It's a start. People get that particulate pollution and smog directly affects their health. That's why the headline of the Sun today screams Sitting in traffic can damage your health the same as passively smoking 180 cigarettes every year, while at the same time the paper promotes climate denial. And if particulate pollution is the gateway to getting rid of gas and diesel cars, we are not going to argue the point.

To clean our air we have to stop pollution at the source
Filters on buses and smog-eating towers are not the answer.

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