How Pedestrians Can Protect Themselves From Diesel Exhaust

Don't hold your breath waiting for VW to clean up its diesels. Do hold your breath while crossing the street

2 min read
How Pedestrians Can Protect Themselves From Diesel Exhaust
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I have a doctor friend, a lifelong germaphobe, who always holds his breath whenever someone walking toward him sneezes, then lets it out after the fellow has passed him by.

Now I find myself doing the same thing when a diesel vehicle comes along. My hypochondriacal tic began last week, when Volkswagen admitted that it had fitted 11 million diesel cars worldwide with engine-control software that cheats on the standard emissions test. The software clamps down on emissions when it senses that the car is running on a laboratory’s dynamometer, then lets the engine rip when the car is back on the open road.

Here the critical pollutants were nitrous oxides, or NOx. But diesel engines also make a lot of carbon particulates, which are caught in special traps. Even so, a lot of them get out, and like NOx, they’re bad for your lungs. Diesels predominate in European cities, so they’d have been the major source of both pollutants there even if their engine algorithms were honest.

It turns out my breath-holding is almost reasonable. A study presented at the European Respiratory Society's International Congress, in Amsterdam, finds that even a single diesel vehicle can create a brief spike in local particulates—and that these spikes are common on busy avenues but not on quiet back streets.

Lee Koh, a researcher at the Blizard Institute at Queen Mary University, in London, carried a monitor while walking along the two kinds of routes in London during the evening rush hour. Though the busy streets had only slightly higher average particulate levels, they alone showed local spikes. For example, when you stop to cross a busy road and so you are subject to a higher level of pollution compared to when walking away from the traffic,” she said in a statement that accompanied her presentation. 

Some spikes reached above 10,000 nanograms of carbon per cubic meter, which is three times the average rush-hour level in London, one of the most particulate-choked cities in Western Europe.

To avoid those plumes of diesel exhaust, Koh planned her walks with an app called Walkit. It’s just the thing for walkers as they wait for the day when diesel emissions controls use their own considerable brainpower excusively for good—and not for evil.

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We Need More Than Just Electric Vehicles

To decarbonize road transport we need to complement EVs with bikes, rail, city planning, and alternative energy

11 min read
A worker works on the frame of a car on an assembly line.

China has more EVs than any other country—but it also gets most of its electricity from coal.

VCG/Getty Images

EVs have finally come of age. The total cost of purchasing and driving one—the cost of ownership—has fallen nearly to parity with a typical gasoline-fueled car. Scientists and engineers have extended the range of EVs by cramming ever more energy into their batteries, and vehicle-charging networks have expanded in many countries. In the United States, for example, there are more than 49,000 public charging stations, and it is now possible to drive an EV from New York to California using public charging networks.

With all this, consumers and policymakers alike are hopeful that society will soon greatly reduce its carbon emissions by replacing today’s cars with electric vehicles. Indeed, adopting electric vehicles will go a long way in helping to improve environmental outcomes. But EVs come with important weaknesses, and so people shouldn’t count on them alone to do the job, even for the transportation sector.

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