Air pollution may be linked with an increased risk of developing dementia, research suggests.

A London-based study, published in BMJ Open, found an association between the neurodegenerative condition and exposure to nitrogen dioxide and microscopic particles known as PM2.5.

Alzheimer’s Research UK described it is a “growing area of research”, but said the results should be treated with caution.

The researchers, from the University of London, Imperial College and King’s College London, used anonymous patient health records from the Clinical Practice Research Datalink, which collects data from GP practices.

They focused on 131,000 patients aged between 50 and 79 in 2004, who had not been diagnosed with dementia, registered at 75 general practices within the M25.

The health of the patients was tracked for an average of seven years, until they were diagnosed with dementia, died or left their GP practice.

Between 2005 and 2013, a total of 2181 patients (1.7 per cent) were diagnosed with dementia, 39 per cent of whom had Alzheimer’s disease and 29 per cent of whom had vascular dementia.

These diagnoses were found to be linked to ambient levels of nitrogen dioxide and PM2.5, based on estimates taken near the homes of patients in 2004.

Those living in areas with the top fifth of nitrogen dioxide levels had a 40 per cent increased risk of being diagnosed with dementia compared with those living in areas with the lowest, the researchers said.

A similar increase was seen with levels of PM2.5, they added.

The associations could not be explained by factors known to influence the development of the condition, but the links were more consistent for Alzheimer’s disease than vascular dementia.

The authors said:

“With the future global burden of dementia likely to be substantial, further epidemiological work is urgently needed to confirm and understand better recent findings linking air pollution to dementia.

“Our results suggest both regional and urban background pollutants may be as important as near-traffic pollutants.

“The cause of these neurodegenerative diseases is still largely unknown and may be multifactorial.

“While toxicants from air pollution have several plausible pathways to reach the brain, how and when they may influence neurodegeneration remains speculative.”

Read more: Future Build

Exclusive: Critics have played down ability of current electric cars to reduce CO2 levels, but new analysis shows significant impact

Replacing a fossil fuel-powered car with an electric model can halve greenhouse gas emissions over the course of the vehicle’s lifetime, according to a new report.

The finding challenges reports by the UK press, other transport research groups and the fossil fuel industry that have underestimated the rise of electric vehicles (EVs) and their capacity for cutting emissions.

Released ahead of the world’s first zero emission vehicle summit in Birmingham, experts hope these results will drive a rapid switch to electric vehicles.

It is well established that a transition to electric vehicles will immediately reduce toxic air pollution, but the impact on carbon emissions has been less clear.

Critics have pointed to the carbon-intensive process of battery manufacture and the relatively small share of Britain’s electricity supply coming from renewables as factors that stop EVs reaching their full CO2-cutting potential.

“The take up of EVs in the UK, as elsewhere, continues to grow fast and sales have just passed 4 million globally,” said Andy Eastlake, managing director of the Low Carbon Vehicle Partnership.

“While no one doubts the air quality benefits of zero tailpipe emissions, critics often question the overall life cycle greenhouse gas impacts.”

However, the new European Climate Foundation-commissioned report used 2017 data to demonstrate that owners of EVs – particularly smaller models – are already playing a big role in helping the climate.

Transport is now the sector that contributes most to the UK’s greenhouse gas emissions, and the Committee on Climate Change has urged the government to improve on their current plan to ensure all new diesel and petrol vehicles are banned from 2040.

In their role as the government’s climate advisers, the committee has called for “more stretching targets” to ensure most new cars and vans are electric by 2030.

Transport secretary Chris Grayling revealed his “Road to Zero” strategy in July to make the UK “the best country in the world in which to develop and manufacture zero-emission vehicles”.

Aurelien Schuller from French consulting firm Carbone 4, one of the report’s co-authors, said their new study revealed “there is no time to waste in the UK’s transition to EVs”.

“Thanks to an already-significant decarbonisation of its electricity generation through coal phase-out the UK is already in a position to make significant cuts in the greenhouse gases from its transport sector,” he said.

The research concluded that a smaller EV produces around 15 tonnes of CO2 from construction through to scrapping, compared to an average of 32 tonnes for the equivalent petrol or diesel car.

Read more: Independent