LONDON—A British government report about fracking, which concluded that the method of shale oil or gas extraction increases air pollution, was left unpublished for three years and was only made public just four days after the firm Cuadrilla was given the go-ahead to start the practice in Lancashire.
The report warned that nitrogen dioxide would rise 1 percent to 4 percent and volatile organic compounds by 1 percent to 3 percent on a UK-wide basis, but locally the impact would be “substantially higher.”
“Impacts on local and regional air quality have the potential to be substantially higher than the national level impacts, as extraction activities are likely to be highly clustered,” the report said.

The increased pollution levels aren’t just attributable to fracking itself, but also to the industry that surrounds it, such as diesel generators and large trucks that travel to and from sites.
Fracking is controversial because of the huge amounts of water that must be brought to the site, and the potential for groundwater contamination by carcinogenic chemicals.
Impact on Air Quality
A spokesman for the Department of Environment, Food and Rural Affairs, told The Guardian newspaper that the report had been based on American data and was published as soon as it had been fully signed-off by lawmakers.However, professor Paul Monks, chair of the Air Quality Expert Group, told the paper that the 2015 report remained valid in its assessment that there would be increased air pollution.
“That hasn’t changed,” he said. “If you have any industrial process at a local level, you are going to get an impact on air quality.”
Furthermore, the report’s figures were based on an estimation of 400 fracking wells in the UK, but the report estimates there could be as many as 12,500 in the future.
“If you increase the amount of wells, you are bound to broadly increase [pollution],” Monks said.
Some areas of the UK already have illegally high levels of nitrogen oxides, so any increase from future fracking activities could be dangerous.
“Air pollution is already a public-health crisis that cuts 40,000 lives short every year, and this report is yet more evidence of why we shouldn’t start fracking,” said Connor Schwartz from Friends of the Earth, according to The Guardian.
Andres Manuel Lopez Obrador said at a news conference: “We will no longer use that method to extract petroleum.”