Chronic effects of Air Pollution Begin Before Birth and are Life Long

The February 2020 edition of Air Pollution News, the newsletter published by the All Party Parliamentary Group on Air Pollution, published an article by Dr Robin Russell-Jones.

APPG Newsletter February 2020

Air Pollution is a global problem. 90% of the urban population worldwide are exposed to levels above the WHO guideline limit for small particulates (PM2.5) of 10 microgrammes per cubic metre of air (µg/m3). [1] Recent studies estimate that air pollution causes 8.8 million premature deaths globally, which represents 15.7% of all deaths. [2] This makes ambient air pollution the greatest preventable cause of death globally, bigger even than smoking at 7.2 million deaths.

The new estimate for mortality in the UK is 64,000 premature deaths annually. UK citizens lose on average 2.2 years of life due to a health hazard that is beyond their control. These latest estimates are based on 41 studies from 16 different countries. [3]

Excess mortality is only a small part of the total picture. A joint Royal Colleges report from 2016, based on 40,000 deaths annually, estimated that air pollution in the UK costs the economy £20 billion per annum, with mortality contributing only 8% of the total.[4] The rest relates to morbidity – in other words the chronic effects of air pollution which begin before birth, and persist throughout life. This review will examine some of these other effects.

“Air Pollution costs the economy £20 billion per annum, with mortality contributing only 8% of the total.”

Birth weight

Birth-weight is a critical measure. An analysis of 32 studies linking pregnancy outcomes with the level of small particulates (PM2.5) concluded that each increase of 10 µg/m3 in PM2.5 lowers birth-weight by 16 grams.[5] It is well known that smoking during pregnancy also lowers birth weight, but mothers have the option of stopping, and most do. Living in urban areas does not give pregnant women this option. In Central London pregnant women are exposed to a level of small particulates that will lower the birth weight of their baby by around 24 grams. It is the equivalent of passive smoking twenty four hours a day for 9 months.[6]

Levels of PM2.5 in the capital are below the annual EU limit of 25 µg/m3, but the health effects of small particulates are without threshold. The EU commission are currently reviewing the Ambient Air Quality Directive and are likely to lower the annual limit. In the US, the legal limit is 12 µg/m3, and 8 µg/m3 in Australia.

During the Olympic Games in 2008, the Chinese Government made every effort to reduce pollution levels in Beijing, notably by restricting vehicle access, and birth weight increased.[7] The maximum benefit (23 grams) was for women who were in the last trimester of their pregnancy during the Olympic Games – in other words the stage of pregnancy associated with maximum foetal growth.

Exposure in utero

Low birth weight is linked to a host of adverse outcomes in later life, including lower IQ. Evidence also exists for a direct impact of pollution during pregnancy. Polycyclic Aromatic Hydrocarbons (PAHs) are generated by any combustion process, so members of the public are exposed from activities such as smoking, cooking, domestic fires, and of course traffic, particularly diesel. Researchers in New York have reported that exposure to PAHs during pregnancy in non-smoking mothers is linked to developmental delay at 3 years;[8] an IQ reduction of 4-5 points at 5 years;[9] increased anxiety, depression and inattention at 6-7 years;[10] reduced surface white matter in the brain at 8 years;[11] and delayed self-regulatory behaviour that was most significant at 11 years.[12]

These observations have not yet been replicated in the UK. Even so the situation may be worse as diesel vehicles represent a much larger proportion of the UK car market than in the US. Since 2000 the proportion of new vehicles which run on diesel has increased from 14% of the new car market to almost 50%. Levels of Benzo-a-pyrene, the only PAH monitored in the EU, have increased by 52% at traffic monitoring sites since 2000.[13]

Effect on IQ

These observations have profound implications for public health and educational attainment. UK children and teenagers are currently suffering a mini epidemic of mental health problems which the medical profession are struggling to explain. Commentators have targeted social media, but the toxic impact of air pollution on developing brains is equally worthy of attention, and a vital area for further research.

Thus air pollution has also been linked with IQ deficits in teenagers and a recent London based study showed higher rates of depression amongst teenagers exposed to higher levels of air pollution.14,15 It could be argued that these associations are not causal, but intervention studies are compelling and cannot be dismissed so easily. For instance, a recent US study demonstrated an increase in the cognitive performance of school children when air filters were fitted to schools in Los Angeles.[16]


There are also data showing that air pollution also impacts cognitive function in later life. A systematic review in 2016 identified 31 studies linking air pollution with cognitive decline: 15 in the Americas, 5 in Asia and 11 in Europe.[17] In 2017 a study of 2.2 million older adults living in Ontario showed that their chances of developing dementia increased the closer they lived to a major highway, indicating a dose-response relationship for traffic-derived pollution and dementia.[18] In 2018 a study of 75 GP practices in Greater London showed that the chances of developing dementia was linked to ambient levels of both PM2.5 and NO2.[19] The authors concluded that 14% of dementia cases in the UK are attributable to air pollution.

Measures needed

It is obvious that the UK Government should be doing more to mitigate these health effects.

HMG could increase the tax on diesel, introduce a diesel scrappage scheme, bring forward the phase-out date for fossil fuel vehicles from 2035 to 2030, and give councils the powers to identify and fine highly polluting vehicles at the roadside.[20] They should also introduce WHO limits by 2030 at the latest with a mandatory air quality standard for PM2.5 of 10 µg/m3, and an intermediate target of 12 µg/m3 by 2025.

Instead, DEFRA has produced a Clean Air Strategy which conspicuously fails to address the problem posed by diesel.[21] It contains a commitment to halve the number of people in the UK exposed to levels above the WHO limit for PM2.5 by 2025. This is not a standard. This is an aspiration that lacks any legal force

It is for these reasons that the UK needs a Clean Air Bill and a National Clean Air Agency tasked with responsibility for both indoor and outdoor air quality.

Dr Robin Russell-Jones is Scientific Advisor to the APPG on Air Pollution. He was previously Chair of CLEAR, The Campaign for Lead Free Air.


  1. Landrigan P et al. ‘The Lancet Commission on pollution and health.’ Lancet (2018); 391: 464-512
  2. Lelieveld et al. ‘Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions.’ European Heart Journal, (May 2019); vol.40: 1590-96:
  3. Burnett R et al. ‘Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter.’ Proceedings of the National Academy of Sciences of the USA (2018); 115: 9592-9597 15
  4. Royal College of Physicians and the Royal College of Paediatrics and Child Health ,‘Every Breath We Take: The Lifelong Impact of Air Pollution’ (2016):
  5. Sun X et al. ‘The association between birth weight and exposure to fine particulate matter (PM2.5) and its chemical constituents during pregnancy: a meta-analysis.’ Environ pollution (2015); 211: 38-47.
  6. Smith R et al. ‘Impact of London’s road traffic air and noise pollution on birth weight: retrospective population based cohort study.’ BMJ (2017);359:j5299
  7. Rich D et al. ‘Differences in birth weight associated with the 2008 Beijing Olympics air pollution reduction: results from a natural experiment.‘ Environ Health Perspect (2015);123: 880-87
  8. Perera F et al. ‘Effect of prenatal exposure to airborne polycyclic aromatic hydrocarbons on neurodevelopment in the first 3 years of life among inner-city children.’ Environ Health Perspect (2006); 114: 1287-1293’
  9. Perera F et al. ‘Prenatal airborne polycyclic aromatic hydrocarbon exposure and child IQ at age 5 years.’ Pediatrics (2009); 124: 195-202
  10. Perera F et al. Prenatal polycyclic aromatic hydrocarbon (PAH) exposure and child behaviour at age 6-7 years. Environ Health Perspect (2012); 120: 921-926.
  11. Peterson B et al. ‘Effects of prenatal exposure to air pollutants (Polycyclic Aromatic Hydrocarbons) on the development of brain white matter, cognition, and behaviour in later childhood. ‘ JAMA Psychiatry (2015); 72: 531-40.
  12. Margolis A et al. ‘Longitudinal effects of prenatal exposure to air pollutants on self-regulatory capacities and social competence.‘ Journal of Child Psychology and Psychiatry (2016); 57: 851-60.
  13. European Environment Agency 2016 report. EEA report no 28/2016:
  14. Wang P et al. ‘Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis.’ PLOS ONE (2017); 12(12): e0188731.
  15. Roberts S et al. ‘Exploration of NO2 and PM2.5 air pollution and mental health problems using high-resolution data in London-based children from a UK longitudinal cohort study.’ Psychiatric Research 2019; 272: 8-17.
  16. Gilraine M et al. ‘Air Filters, Pollution and Student Achievement.‘ EdWorking Paper No 20-188. (Jan 2020)
  17. Clifford A et al. Exposure to air pollution and cognitive functioning across the life course- A systematic literature review. Environ Research (2016); 147: 383-398.
  18. Chen H et al. ‘Living near major roads and the incidence of dementia, Parkinson’s disease, and multiple sclerosis: a population-based cohort study.’ The Lancet (2017); 389:718-726.
  19. Carey I et al. ‘Are noise and air pollution related to the incidence of dementia? A cohort study in London England.’ BMJ Open (2018);8:e022404.doi:10.1136/bmjopen-2018-022404
  20. Russell-Jones R. ‘Air pollution in the UK: better ways to solve the problem.’ BMJ (2017); 357:j2713 doi: 10.1136? bmj.j2713.
  21. DEFRA. Clean Air Strategy Published Jan 14. 2019. Ref PB14554. GOV.UK :


Act now on air pollution



The Observer, 2 January 2020:

Local authorities should be congratulated for banning vehicles from city centres (“Is this the end of the road for cars in Britain’s cities?”, Focus). Diesel vehicles are a particular problem as they generate ultra-fine particles, which are the most dangerous biologically. It had been assumed that diesel emissions would become less of a problem with the introduction of stricter emission standards, but recent testing has shown that diesel filters emit a huge number of ultra-fine particles when the filter is automatically decoked every 300 miles. Pressure from car manufacturers has ensured that these emissions are not included in EU vehicle emission tests.

Evidence as to the health impact of air pollution is also accumulating. A recent study showed that academic performance improved after air filters were fitted to schools in Los Angeles, providing key evidence of a causal link. After Brexit we will no longer be protected by EU air quality standards, and the government’s forthcoming environment bill is a poor substitute for EU law. We urgently need a new clean air act, and a national clean air agency to enforce it.

Dr Robin Russell-Jones, scientific adviser, all-party parliamentary groups
Geraint Davies MP, chair, all-party parliamentary group on air pollution
House of Commons, London W1A

UK’s energy plans should be much more ambitious


Financial Times, 8 May 2019:

Fracking may soon be a dead duck, but there are pivotal decisions on the horizon which will determine the shape of our energy policy in the coming decades, as well as the prospects for future generations (“Fracking tsar resigns saying industry is being wasted”, April 29).

The government is gambling on a combination of nuclear and offshore wind to decarbonise our electricity supply, but nuclear is looking increasingly uncertain, both technologically and financially, while offshore wind is incapable of meeting peak demand during windless conditions. The government needs to be far more ambitious: rather than subsidising fracking it should promote geothermal energy. It should remove the obstacles it has placed in the way of onshore wind, and reconsider its irrational decision to ditch the tidal barrage in Swansea bay. In addition it should urgently reverse its decision to discontinue the feed-in-tariff for solar power.

In the longer-term It could commission a multi-centre research programme into better methods of storing energy, including compressed air, and evaluate the capacity for pump storage in the UK. Finally it should reintroduce zero-carbon homes for new build, and subsidise a Green deal for existing homes. This list is by no means comprehensive, but it underlines the failings of current policy, and highlights the challenges that lie ahead.

Dr Robin Russell-Jones
Help Rescue the Planet,
Marlow, Bucks, UK

Green Brexit


The Times, 16 August 2019:

You are right to question the weaknesses in the government’s proposal to establish an Office for Environmental Protection (OEP) after Brexit (“Green Brexit”, leading article, Aug 14). Climate change, for example, is specifically excluded from the remit of the OEP, as is indoor air pollution. As regards outdoor air quality, the UK has been in breach of EU air quality standards for nitrogen dioxide since 2010, and the government has suffered three defeats in the High Court over its failure to implement effective action. Having resisted legal judgments and failed to comply with EU air-quality standards for more than eight years, is it credible that the government would now seek to create an even more effective domestic system for scrutinising government policy?

It needs to be remembered that between 2003 and 2016, the EU Commission started 753 actions against the British government, of which 120 related to the environment. That equates to nine environmental actions every year. Most were settled, but 29 cases reached the European Court of Justice. In order to replicate this level of scrutiny at a domestic level, the OEP will need to be truly independent: it will need significant resources, as well as sufficient powers to investigate, gain access to relevant data, issue legally binding enforcement notices and monitor compliance. Ultimately it will need the power to take government ministers to court. It is not clear if any of these requirements will be met by the ill-defined proposals in the Draft Environment Bill that was updated last month.

Dr Robin Russell-Jones

Scientific advisor to the all-party parliamentary group on air pollution

Geraint Davies MP

Group chairman, House of Commons

Getting to grips with the climate crisis


The Guardian, 27 July 2019:

Our political system has been hijacked by a cabal of ideologically driven free marketeers with no democratic mandate. Air pollution and climate change, the two most urgent issues confronting society, are nowhere mentioned in the bubbles of bombastic rhetoric generated by our new prime minister. Boris Johnson’s main contribution to air quality as mayor of London was to cancel the western extension of the congestion zone. As for climate change, he presided over a 60% reduction in climate attaches as foreign secretary and subsequently accepted an expenses-paid trip to the US courtesy of the American Enterprise Institute, a fossil-fuel supporting free-market thinktank partially funded by the Koch brothers. I no longer recognise our leadership as embodying British values. I feel I’m living in a foreign dictatorship consumed by profit and self-interest.
Dr Robin Russell-Jones
Chair, Help Rescue the Planet

Methane releases cancel out benefit of switch to gas


Financial Times, 19 June 2019:

The main cause of rising atmospheric methane has been the subject of intensive research, but we are not as ignorant as Professor Jonathan Stern makes out. (Letters, June 5). Methane levels plateaued in the 1990s but have been rising again over the past decade by 8 parts per billion a year. Tropical wetlands and fossil fuel releases are both potential sources, but this debate was resolved by a Nasa-led study published in December 2017 which concluded that fossil fuels were contributing more than biogenic sources to the extra methane. Prof Stern is also mistaken if he thinks that oil and gas facilities can provide data that will clarify the amount of methane being released, since ground-based measurements consistently underestimate the extent of leakage. Aircraft sampling and satellite measurements over the US have produced higher values equivalent to 1.5 per cent of natural gas production. This is a crucial observation because methane releases amounting to 2 per cent of production cancel out the climate change benefit of burning gas instead of coal. Fracked gas probably releases more methane than conventional gas due to the greater number of wells. Liquefied natural gas has a larger carbon footprint than coal as the process of liquefying gas is very energy intensive. So the current strategy of the fossil fuel industry, which is to replace coal with gas, and to market LNG as a clean fuel, is based on a total misconception.

Dr Robin Russell-Jones
Scientific Adviser, All-Party Parliamentary Group on Air Pollution,
Marlow, Buckinghamshire, UK

Air pollution, ill health and the need for a 21st-century Model T Ford


The Guardian, 23 May 2019:

The harmful effects of air pollution during early life deserve greater attention (Air pollution damages ‘every organ in the body’, 18 May). Ongoing research in the US has reported that exposure during pregnancy to polycyclic aromatic hydrocarbons (PAHs), a constituent of diesel exhaust, is linked to developmental delay at three years, an IQ reduction of 4-5 points at five years, increased anxiety, depression and inattention at six to seven years, a reduction in surface white matter in the brain at eight years, and delayed self-regulatory behaviour which became most significant at 11 years. These data are “preliminary” only in the sense that they have not yet been replicated. Benzo-a-pyrene (BaP) is the only PAH routinely monitored by the EU. Due to the rapid growth in the sale of diesel vehicles since 2000, levels of BaP at traffic-monitoring sites has increased by 52%.

These findings have huge implications for public health, educational attainment and the high level of mental health problems currently afflicting schoolchildren in the UK. It is beyond belief that the government’s only response is a vague commitment to halve the number of people exposed to levels above the WHO limit for small particulates by 2025. This is not even a target; it is an aspiration that is legally unenforceable.

Dr Robin Russell-Jones Scientific adviser

Geraint Davies MP Chair, all-party parliamentary group on air pollution

Can we humans save ourselves from self-destruction?


The Guardian, 8 May 2019:

There is a strong case for dating the start of the Anthropocene to 1950, since which time a million species have become threatened; 1950 coincides with the growth of international travel, leading to the introduction of alien species into vulnerable populations which then collapse. Back in 1950, world population was one-third of its current level. A combination of antibiotics, vaccination programmes and ineffective family planning have seen human numbers rocket past 7 billion, and they are still rising. Finally the demands of humanity have led to deforestation and widespread loss of habitat in every part of the globe.

It is entirely appropriate that the UN and other institutions produce reports documenting the disappearance and decline of most species on Earth. But they will have no impact at all unless they are accompanied by measures to limit human numbers.
Dr Robin Russell-Jones
Chair, Help Rescue the Planet


Dieselgate and the unintended consequences of anti-idling drive


The Guardian, 25 March 2019:

In the US, the Dieselgate scandal has resulted in prosecutions against VW personnel and multibillion dollar fines (Where’s there’s smoke…, 22 March). In Europe, no one has been charged and nobody has gone to jail, though the EU commission has threatened action against the UK government for failing to prosecute VW.

Defeat devices result in higher emissions of nitrogen dioxide, but the real danger from a health perspective are small particulates, notably the ultra-fine nanoparticles that can penetrate tissue, reach a placenta and cross the blood-brain barrier. These are largely present in exhaust emissions, so while all vehicles generate particulates from tyres and brakes, researchers have demonstrated that medical effects such as low birth weight are tied more closely to exhaust particulates than to friction particulates. This is important as the government likes to pretend that all particulates are equivalent, regardless of the source. Thus its clean air strategy emphasises the contribution of secondary particulates generated from agriculture etc, even though these contain little in the way of ultra-fine particles. It is disheartening that the UK government seems more anxious to protect the interests of car manufacturers than the health of its own citizens, but this situation is likely to worsen post-Brexit.

Dr Robin Russell-Jones Scientific adviser

Geraint Davies MP Chair, All-party parliamentary group on air pollution