Road traffic dropped by 18 percent, and PM-10 pollution dropped by 6 percent.
Back in March, air quality in Paris got so awful that the city took some drastic measures. With weather patterns keeping noxious particulate pollution close to the ground, the city made all public transportation free of charge. The next day, they went one step further, banning all cars with odd-numbered number plates from driving within the city proper. This unprecedented move is now back in the news for a compelling reason: Apparently, it worked.
According to Paris air quality monitor Airparif, keeping odd-numbered cars out of central Paris for a single day made a substantial difference. Within Paris proper, road traffic dropped by 18 percent that day, with drops of 13 percent in the Petite Couronne area that surrounds inner Paris. In the suburbs further beyond, traffic dropped by 10 percent. When compared to the seven days before, all this reduced levels of pollution by PM-10 within the city by 6 percent, with levels 10 percent lower than normal at rush hour on the Beltway. Nitrogen dioxide levels, meanwhile, dropped by 10 percent overall, and by 30 percent on the Beltway at rush hour.
A 6 percent drop may not sound massive, but bear in mind the circumstances in which it happened. This is just a single day of driving restrictions we're talking about. It took place under weather conditions when (thanks to a combination of very cold air by night and rainless, largely windless sunshine by day) particulates were flurrying around Paris’ lower atmosphere like white flecks around a snow globe, unable to escape. The drop thus happened under conditions when natural dispersion of pollution was especially difficult. Given that conditions had worsened over the preceding week, it’s also likely that the pollution drop from the days immediately before that Monday, March 17, was yet higher than the 6 percent contrast with Monday, March 10. All told, the drop shows the clear benefits to be had from a situation that prioritizes public over private transport.
Cars and trucks are not the only culprits when it comes to air pollution, of course. While according to this article from Le Monde, 51 percent of overall particulate pollution in the Paris region still comes from road traffic, it’s the region’s industries that create the most PM10 emissions (30 percent of the total). Creating bans or restrictions that hinder individual drivers, without making bigger organizations that are just as responsible pull their weight, would inevitably cause some resentment. As yet, no one has seriously advocated maintaining what was an emergency ban under normal conditions.
The figures released by Airparif do still provide ammunition for the idea of introducing low emissions zones and/or congestion charge zones, as London has. Refusing to target average Joe drivers with legal restrictions inevitably leads to something else: choosing to target average Joe city dwellers with pollution that can and often does slash their life expectancy. It only took a day to see a significant cut in Paris’ levels of potentially lethal particulates. If we saw policies seriously limiting car use within cities, imagine what a huge positive effect it could have on city dwellers’ health.