Cleaning polluted urban air is no easy task. But as smog levels from Athens to Beijing to Salt Lake City increasingly pose a threat to residents’ health, some cities are taking drastic measures to quickly reduce air pollution. Their answer, almost across the board: Get cars off the road. After 30 years of experimenting with various strategies, some cities have found more success than others.
No-drive days: no luck
Mexico City’s smog problems began in earnest in the 1950s as a population boom brought nearly 17 million new people to the valley, more than quadrupling the city’s population. That, combined with the city’s air-trapping geography—the metropolis is situated, at nearly 7,500 feet, in the crater of an extinct volcano that encircles the city with mountains—created some of the worst air in the world. Sound familiar? Anyway, Mexican City officials began tackling the problem way back in 1989, implementing the Hoy No Circula “Today it Doesn’t Move” program, which banned certain cars from driving one day each week based on the last digit of their license plate. Three years later, the United Nations gave Mexico City the title of most polluted city on the planet. What went wrong?
Turns out, disgruntled drivers were circumventing restrictions by purchasing additional cars, many of them old and highly inefficient. This loophole strategy led to a 13% rise in carbon dioxide following an initial decline of 11%.
Other cities that have implemented no-drive days have witnessed similar outcomes. In Bogota, where the Pico y Placa “Peak and Plate” program limits driving during peak traffic hours two days a week, pollutant concentrations worsened as citizens began driving more during off-peak hours. In Paris, the impact of short-term driving bans during periods of high smog remains unclear although public discontent about the program is well noted.
Low-emission zones: good
A more promising method for reducing vehicle emission pollutants in cities is the Low Emission Zone (LEZs). These designated areas, usually in city centers, bar inefficient vehicles while encouraging use of public transportation or upgrading to cleaner cars. Stockholm, where the first LEZ was implemented in 1996, has seen a 20% decrease in emissions of nitric oxide and nitrogen dioxide, and cut particulate emissions by half. In London, the LEZ closes the city center to private vehicle traffic weekdays during busines hours. Motorcycles, scooters and bicycles are exempt, as are those willing to pay the “congestion charge.” This dual approach has led to a 12% reduction in PM10, nitric oxide and nitrogen dioxide, and a 20% decrease in PM2.5. In addition to implementing the LEZ, Berlin requires a closed catalytic converter on all diesel and gas vehicles. Since the law passed in 2008, the city has seen a decrease of 12-22% of diesel particulates, with levels of PM10 down 3%.
Low Emission Zones and driving bans are all well and good, but Copenhagen has developed a truly enviable solution to vehicle pollution: world-class bike infrastructure.
Bicycle strategies: best
In Copenhagen, a “cycling superhighway” connects suburbs to the city with 200 miles of bike lanes. The newly built Cykelslangen “Cycle Snake” skyway elevates cyclists above traffic on a two-lane, first-floor level road designed solely for bike traffic. In 2011, the city’s municipal council unanimously adopted a cycling plan titled Good, Better, Best—The City of Copenhagen’s Bicycle Strategy 2011-2025. Through this progressive plan, Copenhagen, which has committed to carbon neutrality by 2025, hopes to reduce cyclists’ travel times while increasing commuter trips made on bikes from 35% to 50%.
In the United States, Minneapolis, recently named America’s Best Bike City by Bicycling magazine, certainly merits attention. According to a 2008 U.S. Census, 4.3% of Minneapolis residents (8,200 people) bike to work, second only to Portland—both cities where bike commuters must endure tough weather conditions, freezing winters or endless rain. Boasting a solid bike infrastructure, Minneapolis and its sister city St. Paul have a combined 84 miles of bike paths and 44 miles of dedicated bike lanes on roads, with plans for an additional 40 miles of lanes.
In Minneapolis, all buses and trains are equipped to carry bicycles. Offices must, by law, have bike storage, with the city funding half of every bike rack installed by a business.
Like Copenhagen, Minneapolis is also home to a thriving bike culture. Cyclists regularly can join in on games of bike-polo or race the Stupor Bowl, the largest alley cat race in the country—women cyclists have their own alley cat race, Babes in Bikeland. It’s the kind of culture that has the city regularly ranking as one of the greenest cities in America.
Salt Lake City claims to have over 150 miles of bike lanes. That number, in addition to commuter roads with actual bike lanes and safety infrastructure, counts paths like the Jordan Parkway, moderate-traffic streets like 500 East and 1300 South that have no designated bikes lanes but on which cyclists can “share lanes with slower travel speeds,” and high-traffic streets such as State Street and 700 East on which no sane bike commuter (I feel, as a bike commuter, I can safely say) would travel.
Salt Lake’s downtown GREENbike program has blossomed since its 2013 inception, with 210 bikes at 25 locations now. The charge is $5 per day (in 30-minute increments) or $75 for a year membership.
As ozone levels climb to dangerously high numbers this summer, and as we begin, in autumn, to bemoan the return of winter inversions, let’s take inspiration from Copenhagen, London, Minneapolis, even Mexico City. Consider what other people are doing to clean their air and save their lungs and ask, could we do that, too?
We can’t change the inversion-inducing geography we live in, but we can change our habits and local laws. We can do something about our pollution.
Clare Borighter is a Ute Fire Tower lookout ranger at Ashley National Forest and an editor at First Class, an online literary journal. She is a former CATALYST intern.