The official death toll from the toxic fumes that belch from vehicle exhausts has nearly doubled, meaning that more than 3,500 people die every year from air pollution in Scotland.

New figures from the UK government estimate for the first time the number of deaths blamed on nitrogen dioxide gas, as well as tiny sooty particles. Taken together these boost the number of annual deaths across the whole of the UK from 29,000 to over 50,000.

Environmentalists estimate that this translates to at least 3,500 deaths a year in Scotland, compared to a previous estimate of 2,000. They also attack new Scottish Government proposals to tackle air pollution as “incomplete, vague and lacklustre”.

Air pollution from cars, vans, buses and lorries can trigger heart attacks, strokes and cause infections. The emissions aggravate lung diseases, and can worsen the suffering of hundreds of thousands of people with asthma.

The new estimates of deaths were prompted by a Supreme Court ruling in April requiring the UK government to take urgent action to tackle illegal levels of air pollution in cities. Last week both the UK and Scottish governments launched new public consultations on their plans.

Tucked away in a report from the UK Department for Environment, Food and Rural Affairs was the estimate that nitrogen dioxide caused 23,500 deaths a year in the UK, while tiny particles were responsible for 29,000 deaths a year. “The combined impact of these two pollutants represents a significant public health challenge,” it said.

According to an analysis by Friends of the Earth Scotland, this means that air pollution causes more than 3,500 early deaths in Scotland every year. “This new evidence is truly shocking, hugely alarming and demonstrates that air pollution is a major public health disaster,” said the group’s campaigner, Emilia Hannah.

“If it emerged that thousands of people were dying every year from disease, crime or drugs, the government would be pouring millions of pounds into saving lives and fixing the cause.”

She criticised the Scottish Government’s air pollution consultation for failing to provide essential information, and called for the introduction of fully funded low emission zones. “The public deserves more than vague promises and assurances that our air will be clean. We need to know when and how,” she argued.

Medical experts backed the call for tougher action to cut toxic emissions. “Our research has continuously shown that levels of air pollution can shorten people’s lives and increase their risk of heart disease and stroke,” said James Cant, director of British Heart Foundation Scotland.

“This is a deadly problem and the government has so far failed to fulfil its duty to protect public health by making sure the air we breathe is safe. We hope this is the beginning of quick and effective action to tackle the issue.”

He promised to examine government proposals to make sure they were sufficiently ambitious. “Any kind of delay in bringing air pollution levels in line with European law takes its toll on the health of the UK population,” he stressed.

Fintan Hurley, a government air pollution adviser at the Institute of Occupational Medicine in Edinburgh, welcomed the new estimate of deaths from nitrogen dioxide (NO2). “The estimated NO2 effects are big,” he told the Sunday Herald.

“They show that complying with NO2 air quality standards is much more than just a legal requirement. There are significant public health benefits as well.”

The Sunday Herald revealed in January that legal safety limits for NO2 and tiny particles that should have been met in 2010 were breached on 23 urban streets across Scotland in 2014. They included busy roads in Glasgow, Edinburgh, Dundee, Aberdeen, Greenock, Rutherglen, Kilmarnock, East Kilbride, Falkirk, Perth and Crieff.

David Newbie, professor of cardiology at Edinburgh University, pointed out that the combustion of vehicle fuel produced both NO2 and particulate pollution so it was difficult to separate out their health effects. NO2 could suffer from “guilt by association”, he argued.

But he understood the frustration expressed by campaigners at governments’ failures to produce specific legislative proposals. “I think that the only way to improve air quality is to legislate against it,” he said. “The clean air act and the smoking ban have shown this.”

The Scottish Government suggested that nitrogen oxide emissions had fallen by 67 per cent since 1990, but accepted that further progress was required. “Following consultation earlier this year on a low emission strategy we are working with partners such as local authorities and Transport Scotland to finalise the strategy for publication later this year,” said a government spokeswoman.

“This will draw together in one place a range of existing and additional actions which will support delivery of further improvement in air quality, supporting individuals and communities across Scotland.”

For one lifelong asthma sufferer, 36-year-old Liz Ashton from Edinburgh, this may not be enough. “My asthma is like a litmus test for pollution levels, because the symptoms get so much worse when I am exposed to traffic,” she said.

“For several years, I lived on a busy road in Edinburgh city centre with four lanes of traffic and had to take daily medication. I would wake most nights with a tight chest, wheezing. Seven months ago, I moved out of town, and I am no longer being kept awake at night struggling to breathe.”

She called on Scottish ministers to curb emissions from cars and lorries, and encourage walking, cycling and public transport. “It frightens me that when I lived in the city centre I could have had a fatal asthma attack,” she said.

“People need to understand that air pollution is damaging their health and their children's health. There are much higher rates of childhood asthma than there used to be.”