Obama wants to cut ozone pollution, but Republicans are crying foul over the cost. Europe is being tougher… or is it? Much is obfuscation
"VOTE Republican: vote smogs". I doubt many bumper stickers carried that message during last year's US midterm elections. But choking air and kids dying of asthma may be what the Republican victory delivers.
Republicans now control both houses of Congress and are all for throttling President Barack Obama's plans to lower the federal limit on ozone smog, announced by the US Environmental Protection Agency (EPA) right after the elections. They say it is unachievable, except at vast cost.
This might surprise Europeans, who have been living with a tougher limit for some time. However, an analysis for New Scientist suggests that Europe's limits are less stringent than they appear. And reports from Brussels in recent weeks suggest that anything tougher is off the agenda because of concern about the impact on fragile economies.
Ozone in the stratosphere, miles above the ground, is a good thing, shielding us from cancer-causing ultraviolet radiation. But it is also a strong corrosive oxidant. At street level it triggers asthma attacks, damages children's lung development and causes heart problems in the elderly. It also cuts crop yields, slows tree growth and eats away at textiles – all at levels commonly found in industrialised nations.
The pollutant is unusual in that we don't emit much directly. It is largely a secondary product, created photochemically. Nitrogen oxides from burning fuel react in sunlight with volatile organic compounds from solvents plus vehicle engines and oil refineries. This cocktail brews especially in summer, though it takes a few hours for the concentration of ozone to peak, so the highest levels are often found in suburbs or countryside downwind of urban areas, where pockets of pollution will have drifted in those few hours.
The health risks scale up with the duration of continuous exposure; regulators mostly measure 8-hour averages. Places breach limits when they have too many days with excessive amounts over 8-hour stretches.
The first US ozone standard was set in 1979, at 120 parts per billion. It was lowered in 1997 to 84 ppb and again in 2008, under President Bush, to 75 ppb. Many major US cities such as Chicago, Dallas, Houston and much of California regularly breach the Bush limit.
But doctors say the limit should be lower still. The World Health Organization reports that healthy adults and children exposed to ozone at 60 ppb for several hours experience inflamed lungs and breathlessness. In 2005, the WHO recommended a limit of 50 ppb.
Regulators have been timid. The Obama administration initially vetoed a tougher stance. But last November, the EPA finally proposed a new limit of between 65 and 70 ppb. It would come into force between 2020 and 2037, with problem cities getting most time to adjust. "Bringing ozone pollution standards in line with the latest science will clean up our air [and] protect those most at risk," said EPA administrator Gina McCarthy. But 2037 is a long time to wait if you have asthma.
Opponents say meeting such a limit will require expensive retrofitting of scrubbers to remove nitrogen oxides from power plant fumes, and either new technology for vehicle exhausts or limits on transport. It "could cost up to $270 billion a year and place millions of jobs at risk", according to the US National Association of Manufacturers. The EPA dismisses that, reckoning that a 65 ppb limit would cost $15 billion a year in return for health benefits worth twice as much: annually, up to 4300 fewer premature deaths, as many as 960,000 fewer childhood asthma attacks, and a million fewer missed schooldays.
In the dog days of his administration, Obama is keen to use his executive powers to bring on environmental measures of this sort. But Congress is not in a mood to lie down. Both the Senate and House of Representatives are looking at Republican proposals requiring the EPA to consider the impact of air-quality rules on jobs, something it is not allowed to do at present. Republicans may also take aim at EPA funding. Smog sceptics, like climate sceptics, seem to have subjugated environmental concerns to their narrow political agenda.
All this makes Europe look good. A European Union ozone limit of 60 ppb – deemed unattainable in the US – has been in force since 2010. But US and European limits are not directly comparable, and here's why.
In the US, being in breach of the regulations means exceeding the limit on four or more days in a year, averaged over three years. So 11 breaches in any three-year period is fine, but 12 is not. In Europe, the limit can be exceeded up to 25 days a year, again averaged over three years. So up to 75 bad-air days are allowed in that time. That's a lot, but even so large parts of southern Europe failed that test for the period 2011 to 2013, because of a spike during the hot summer of 2013.
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