Bill Ford, chairman and chief executive of Ford Motor, frequently touts the company's environmental friendliness. Ford was the first American car company to offer a gas/electric hybrid vehicle that could run on electricity alone (the Escape Hybrid SUV), and 10.4 acres of plants grow on the roof of the automaker's Dearborn Truck Plant.
But our first-ever ranking of the least environmentally friendly new cars isn't just dominated by pickups and SUVs; five of the seven cars on our list are made by Ford Motor. And though domestic manufacturers are rolling out low-emission gas/electric hybrids, such as General Motors' Saturn Vue Green Line SUV, all seven of the market's least green cars, according to the U.S. Environmental Protection Agency's most current data, are American -- strong evidence that U.S. automakers are not as serious about clean vehicles as their foreign counterparts are.
In fact, the market's least environmentally friendly car is Ford's $26,000, full-size E-Series van, which gets the EPA's lowest-possible scores for air pollution and greenhouse-gas emissions: 0 out of 10 on both. Compare that with the market's most environmentally friendly cars, Honda Motor's Civic Hybrid and Toyota Motor's hybrid Prius sedan, which have air-pollution scores of 9.5 and greenhouse-gas scores of 10.
Even in apples-to-apples comparisons of similar vehicle types, the American cars come up short. The dirtiest configuration of Nissan Motor's full-size Titan pickup has poor air-pollution and greenhouse-gas scores, but it's still greener than Ford's most polluting F-150 pickup.
Why are the American cars so bad for the environment? And why does Ford dominate the list?
For one thing, we evaluated only the dirtiest variant of each model range on the market, and the configurations tested by the EPA favor some cars over others. The Ford F-150 truck we mentioned is dirtier than the dirtiest Nissan Titan. But the Titan in question uses two-wheel drive and a five-speed transmission, while the F-150 in question uses a four-speed transmission and four-wheel drive, both of which use more fuel and result in more pollutants. (Other factors, such as tire size, vehicle weight and aerodynamics, also influence emissions.)
"It's not a surprise that the numbers are down for the largest, most capable vehicles," a Ford spokeswoman told us. She said the company has a harder time controlling emissions for models with bigger sizes and larger engine options, but pointed out that Ford also makes some of the market's most environmentally friendly vehicles, such as its Escape Hybrid SUV.
DaimlerChrysler's Dodge subsidiary, the only other carmaker on the list, expressed a similar lack of surprise.
"It's to be expected," said a Dodge spokesman in a phone interview. The cars on the list "are the thirstier vehicles. They're bigger. They're heavier."
Another factor in air-pollution and greenhouse-gas scores is the fact that the federal government does not have emissions limitations for many of the pollutants the EPA monitors, such as formaldehyde and carbon dioxide. Meeting emissions regulations is one of the toughest challenges for carmakers; to do so, they often make tradeoffs, improving regulated emissions while increasing emissions of unregulated pollutants. But that doesn't mean the legal pollutants aren't bad.
American automakers may argue that they can't meet pollution standards that don't exist. But Japanese automakers manage to make many of their cars more environmentally friendly. Domestic manufacturers haven't had much incentive to invest in more environmentally friendly designs. Ford's F-Series may pollute the air, but it's also the best-selling vehicle line in America. Buyers are obviously prioritizing size and power, not environmental friendliness.
We ranked cars by combining the EPA's air-pollution and greenhouse-gas scores (we only considered cars with both scores). The lower the combined score, the more environmentally unfriendly the car.
The EPA bases a car's air-pollution score on its output of pollution that produces smog and causes health problems. The major pollutants in exhaust include nitrogen oxides and various organic gases, which combine in sunlight to create smog. Other pollutants include particulate matter, a lung irritant and carbon monoxide, a poisonous gas.
The greenhouse-gas score reflects emissions of carbon dioxide, one of the biggest byproducts of engine combustion.
The EPA bases a vehicle's greenhouse-gas score on its estimated fuel economy and fuel type. The lower the fuel economy, the more carbon dioxide a car emits. The amount emitted per gallon of fuel burned varies by fuel type, since each contains a different amount of carbon per gallon.
Why are the larger vehicles so noxious? According to an EPA spokesman, the problem is "mostly on the greenhouse-gas side of things. They get lower fuel economy," which leads to higher emissions.
One caveat about our rankings: The majority of new models with poor air-pollution scores are not issued greenhouse-gas scores.
The first reason is that heavy-duty trucks and SUVs weighing more than 8,500 pounds are excluded from federal fuel-economy regulations. Since the EPA does not issue fuel economy figures for these vehicles, it can't develop greenhouse-gas scores for them.
The second reason is that the EPA is still gathering information on the newest cars -- the 2007 models, which typically arrive in the fall. Among the 2007 models with the worst air pollution scores, none has a greenhouse-gas score available.
Note: EPA scores came from the agency's Web site. By publication time, the EPA had not confirmed the data.