New study shows tiny magnetite particles from diesel fumes lodge in the brain where they may contribute to conditions such as Alzheimer's.

The research boosts the case to send a tax signal that draws new car purchasers away from diesel – An Taisce.

The study, conducted at Lancaster University and published in the Proceedings of the National Academy of Sciences, found high levels of magnetite, an iron oxide, in brain tissue. Alzheimer’s patients also have high levels of magnetite in brain tissue.

While scientists are keen to stress that the work does not prove that diesel causes Alzheimer’s, Dr Barbara Maher, who lead the study, said that it had become “more urgent and important” to reduce particulates in the air from combustion sources. Diesel vehicles are a key source of particulates.

An Taisce also drew attention to recent World Bank data which puts economic costs on air pollution.[1] Air pollution, the World Bank estimated, cost Ireland:
* €58m in days lost at work every year, and
* €2.2bn in annual welfare losses.

Ireland can ease its air pollution bill, and sending tax signal that draws purchasers of new cars away from diesel would be a good start, according to An Taisce.

Ireland has a massive problem with diesel cars”, according to Charles Stanley-Smith, Communications Officer of An Taisce, noting that “diesel cars in Ireland still account for over 70% of total new sales due to the lower tax rate applied to diesel fuel”.

Ireland taxes diesel 11 cents less per litre than petrol but an inter-departmental strategy group recommended closing this gap over 5 years by increasing the diesel rate by 2.2c annually over this period.

In September, six civil society organisations called on the government to implement the advice of its inter-departmental strategy group [4].

The country needs to get back on track, shifting car sales away from diesel and on to electric vehicles and hybrids” continued Charles Stanley-Smith of An Taisce. Ireland buys the most new diesel cars per head of population in Europe (see graph).

All drivers are at risk as air pollution inside vehicles can be as bad, and sometimes worse, than outside [3].

The new reports follow up recent research confirming the negative effects of diesel. The average diesel car emits at least 10 times more health-damaging pollutants than a petrol car. In 2012 the World Health Organisation confirmed that diesel exhaust fumes are a cause of cancer.

More than 14,000 years of life are lost every year in Ireland due to particulates,[5] and diesel cars are the single largest cause.

According to the six civil society organisations (CSOs) advocating fuel tax reform (the Asthma Society of Ireland, An Taisce, Irish Environmental Network, Green Budget Europe, Transport & Environment and the Irish Cycling Advocacy Network,, “the case to reform the existing profile of Irish car sales, phasing diesel down in a planned way, is overwhelming”.

As well as lodging in the brain, particulates also penetrate sensitive parts of the lungs, causing or worsening respiratory diseases, such as asthma, emphysema and bronchitis. Particulates also aggravate heart disease.

After tax reform, the additional revenue must be used to enhance low-carbon transport, including better public transport, as well as recharging facilities for electric cars”, say the CSOs. “In the immediate term, a radical development of rural transport services is required. The LocalLink programme already in place can be significantly enhanced to facilitate volunteer drivers who are interested in providing community car services. This has already happened for Meath/Louth/North Dublin services, and needs to be extended nationwide. Comprehensive national policy is required so that such services expand in the coming years.”

Ten years from now we do not want to face higher asthma and lung disease levels, and talk about what we should have done in 2016″, the organisations said.

Regarding the impact on haulage, the civil society organisations said that even by 2022, when the 11c diesel tax increase is complete, diesel bought in Northern Ireland will likely remain more expensive than in the Republic. As flagged in a number of recent reports for government, better incentives are needed to encourage the purchase of more fuel-efficient trucks. A major crackdown on diesel laundering is also required.

On climate change, the organisations note that diesel cars, until recently, emitted lower climate change emissions compared to petrol – but always emitted more harmful particulates, highly damaging to health. Efficiency improvements in petrol engines over the past 5 years mean that climate emissions from new petrol and diesel cars are now, on average, approximately equal.

In terms of price impact on consumers, international oil prices are significantly lower than two to three years ago. Calculations show that the annual cost increase would be €67, assuming a full tank of diesel per week, a reasonable sum to avoid higher levels of asthma, lung disease and heart conditions, according to the organisations.

In a clear sign of change, Renault is phasing out diesel engines from its car assembly lines, starting with smaller models. However, before diesel car output slows radically, carmakers will be seeking to offload their diesel car stocks, and principally on the European market. Irish politicians must act swiftly to avoid excessive diesel cars being offloaded on the Irish market.


Charles Stanley-Smith, Communications, An Taisce Tel: +353 87 241 1995
email: [email protected]
An Taisce The National Trust for Ireland


  1. World Bank 2016
  2. European Environmental Agency (EEA) 2015
  3. Air pollution experiment - The Guardian 2016
  4. Tax Briefing: “Diesel, air quality and health”

About An Taisce

An Taisce is a charity that works to preserve and protect Ireland's natural and built heritage. We are an independent charitable voice for the environment and for heritage issues. We are not a government body, semi-state or agency. Founded in 1948, we are one of Ireland’s oldest and largest environmental organisations.