LONDON (Bloomberg) -- The UK's departure from the European Union may free up officials in Brussels to tighten air-pollution regulations everywhere in the region, including in the UK, because of a twist in the free-trade laws likely to remain in force.
The UK has worked to limit EU curbs on vehicle exhaust fumes in the form of nitrogen dioxide, saying it's unable to meet 2010 rules until at least 2030. If UK voters opt to quit the union in a referendum on June 23, one of the primary opponents to those restrictions would lose its seat in the debate where the rules are made.
Even outside the union, the UK would remain beholden to a number of environmental laws including the Air Quality Directive if it opted to remain in the European Economic Area free-trade zone, according to ClientEarth, a group of lawyers that successfully sued the government over its failure to cut pollution.
The comments undercut the idea that the UK would escape rules made in Brussels if it departed the EU.
For the UK, it would be "the worst of all worlds," said James Thornton, CEO of ClientEarth. "It would mean having to comply with air-quality laws which we then can't influence. With a seat at the table on all EU laws, the UK has the power, hard and soft, to influence the direction of EU policy and find practical responses to the environmental problems we face."
With the referendum almost four months away and the result uncertain, there's little discussion about how the UK would manage an exit from the union. Also unknown is whether the UK would want to -- or be able to -- remain in the EEA. That may take years of negotiation to clear up in the event of "Brexit."
Countries such as Iceland, Norway and Lichtenstein that are outside the EU and inside the EEA must enforce the pollution rules even though they have little voice in shaping them in Brussels. Switzerland isn't bound by the directive because it's outside the EEA, despite having its own free trade deal.
The European Commission offers EEA countries like Norway some "decision shaping" in the early stages of drafting a policy, said David Buchan, senior research fellow at the Oxford Institute for Energy Studies. This influence has diminished over time as more EU agencies were set up to advise on regulations, he said.
"If the UK joined the EEA, these directives would apply to the UK under the same conditions as Norway, which is perhaps a little bit of influence at the early stages but no final say in the decision making," Buchan said.
It would be "a major lost opportunity" for the UK to lose its influence over EU environment laws, says Justine Thornton QC, a barrister specialized in environmental law. "The UK has traditionally played a central role in developing environmental standards at EU level," Thornton said. "Whether we've been for what the European institutions want or against, we've been very centrally involved, and to lose that I think is of concern."
Pollution is a growing concern in the UK after London breached EU limits for the whole of 2016 within the first three weeks of the year. Judges in the UK's Supreme Court last year ordered ministers to reduce emissions as soon as possible, prompting the UK to draw up a plan for clean-air zones in five major cities.
"They are completely failing to satisfy the EU Directive at the moment, so the pressure is already on them," Angus Walker, partner at law firm Bircham Dyson Bell, said in an interview.
The UK has adopted the EU Air Quality Directive into national law, which it could theoretically unpick if it left the bloc. It would require departing the EEA for ministers to have a fully free hand, Walker said.
"The government would no longer be bound to keep the standards up, and I can see them inevitably watering them down to compete with other countries economically," Walker said.
Lifting the pollution limits would make it easier to promote dirty infrastructure projects, such as a new runway at London's Heathrow Airport, which will exacerbate London's air quality problem. Walker said the EU directive has the potential to halt Heathrow's expansion. The issue already has energized anti-runway activists including London Mayor Boris Johnson, who is also a leading Brexit proponent.
A spokesman for the Department of Environment Food and Rural Affairs didn't want to comment because the government supports the UK remaining in the EU and is reluctant to speculate on what would happen if it left.
"If we're outside the European Union then yes we can determine our own policy priorities and emissions wouldn't be an absolute requirement as it is now under the EU laws," said Munir Hassan, partner at law firm CMS Cameron McKenna LLP in London. "It would be one among a number of competing priorities we'd look at when deciding what to do."