Achieving cleaner air

In December, Chief Medical Officer Professor Chris Whitty, published his annual report, this time on air pollution

Outdoor air pollution poses significant threats to health including heart disease, stroke, lung disease, cancer and asthma exacerbation. It is known to lead to increased mortality and is also linked to impacts on lung development in children.
The report acknowledges the problems posed by indoor air pollution as well.
Chief Medical Officer Professor (CMO) Chris Whitty said: “Everyone is affected by air pollution, and it is everyone’s problem.
“Air pollution has improved and will continue improving provided we are active in tackling it. We can and should go further – and it is technically possible to do so.”

Health problems
Some of the health problems associated with air pollution that are highlighted by the report include a low birth weight and asthma across every age group. In children, the problems include slower development of lung function, development problems, more wheezing and coughs and the start of atherosclerosis. In adults, problems may be coronary heart disease, stroke, lung cancer, chronic obstructive pulmonary disease and diabetes. In the elderly, problems include accelerated decline in lung function, lung cancer, diabetes, dementia, heart attack, heart failure and stroke.
Dr Charmaine Griffiths, chief executive of the British Heart Foundation, said: “We’re pleased to see the CMO focusing on air pollution in his annual report this year. Research the British Heart Foundation has funded has helped to show just how damaging air pollution can be to our cardiovascular health.
“We have the tools and understanding to make better air quality a reality, but we need to do more. Making sure this report’s recommendations are implemented will help to clean up the air in all our communities and deliver real improvements to the nation’s health.”
It is estimated that the mortality burden of air pollution in England is between 26,000 and 38,000 a year. It has also been noted that improved air quality is associated with improved health outcomes – reductions in air pollution in London have led to reduced hospital admissions for asthma.
Sarah Woolnough, chief executive of Asthma + Lung UK said: “This report by the CMO should act as a rallying call to tackle air pollution. From our very first breath, air pollution has a significant impact on our health. Toxic air not only puts people at risk of potentially life-threatening asthma attacks and dangerous COPD flare-ups, it can also lead to the development of lung conditions including lung cancer.
“Chris Whitty is right to highlight the devastating impacts of air pollution and it is now vital that meaningful steps are taken to protect public health from this invisible threat. This includes schemes that work to get the most polluting vehicles off our roads.”

The report highlights the improvements made to air pollution and also sets out solutions to continue the progress.
The report points out that individuals have little control over the level of pollution that they breathe and that it needs to be seen as a societal problem to solve.
Since the 1980s, outdoor air quality has improved significantly, with air pollutants such as sulphur dioxide from coal and lead from petrol at fractions of their previous levels. Emissions of most outdoor air pollutants have declined steadily, though some, such as ammonia have been static.

Whitty’s recommendations for outdoor air pollution include: accelerating the electrification of light vehicles and public transport; innovation to reduce air pollution from non-exhaust sources such as tyres, and the need for a greater range of options for reducing air pollution from heavy and specialised vehicles; local urban planning supporting reducing air pollution locally – such as reducing air pollution near schools and healthcare settings; and in agriculture, reducing ammonia air pollution emissions through modified farming practices, such as applying slurry directly to soil.

Road vehicles are a main source of air pollutants, including PM2.5 and NO2, and the problem is worse in urban areas where there is large population exposure. Road vehicle emissions have significantly reduced in line with regulations. It is anticipated that emissions from petrol and diesel engines will continue to fall as electric vehicle use becomes more widespread. However, the report points out that this switch should be accelerated. It is also expected that PM2.5 emissions from brakes will continue to fall as regenerative braking becomes more prominent.
Rail transport already uses electrification as its main power source, and compared to fossil fuel combustion, this can lead to reduced air pollution emissions – this is important in urban areas and enclosed spaces such as train stations. The report points out that further electrification is the ideal, but there are other technical solutions that could improve air quality in the interim or permanently. These solutions include power by bi-mode, battery or hydrogen fuel cells.
Aviation and shipping also emit air pollution, especially around ports and airports, which can affect the local population and these industries are lagging behind road and rail when it comes to reducing emissions. The report recommends further reducing the sulphur content of ship and aviation fuels and also using electric power and tugs when aircraft are on the ground.

Government action
The report points out that government action can have a significant impact on air pollution, with central and local government able to influence air quality through regulation and the use of cleaner vehicles for public transport.
Urban planning can have an effect on how people use different forms of transport and can also influence the concentration of pollutants in areas of high building density.
Active travel is an area highlighted in the report that could be improved, with walking, wheeling and cycling having fallen significantly since the 1950s. Reversing this decline would have health benefits outside of reductions in air pollution, with an increase in physical activity. The report calls for improvements to infrastructure for active travel.

Several industries have reduced their emissions over recent decades, with a large improvement in sulphur dioxide emissions, due to a move away from coal and engineered solutions. Regulations have encouraged transition from processes that resulted in high air pollution emissions. The report points out that industries can still reduce their emissions.

The report highlights agriculture as a sector which could significantly reduce its contribution to air pollution, with ammonia pointed out as an important air pollutant. Ammonia emissions have changed very little over the last few decades, though the report points out it is possible to reduce ammonia by using a combination of liquid manure (slurry) covering and changing techniques to apply slurry to fields - moving from broadcast (splash plate) slurry spreading, where much of the NH3 ends up in the air, to more direct methods such as narrow band spreading, trailing shoe or injection significantly reduces emissions.

The report has a whole section dedicated to the NHS: “The health sector, and specifically the NHS, needs to contribute to the effort to improve outdoor air quality and is taking steps to do so.” The report mentions the large estate, workforce and fleet and recommends reducing the combustion of fossil fuels used to heat hospitals and other buildings, as well as electrification of the vehicle fleet.

Indoor air pollution
It is estimated that people spend around 80 per cent of their time indoors, though not as much is known about the sources of and people’s exposure to indoor air pollution. Some pollutants may enter the building from outside, though there are indoor sources as well. Volatile organic compounds and carbon monoxide are emitted indoors and tend to have higher concentrations indoors as well. The report recommends reducing emissions and concentrations of known pollutants and identifying other chemical indoor pollutants with significant health harms.
For indoor air pollution, the recommendations include addressing
a major engineering challenge – ensuring effective ventilation while minimising energy use and heat loss and increased research into tackling indoor air pollution including finding ways to reduce sources of indoor air pollution.
The report points out the role of ventilation as central to reducing indoor air pollution. There is an engineering challenge around maximising ventilation, but at the same time keeping buildings warm in winter and cool in summer and therefore minimising energy and carbon use.

The report highlights the need for research and innovation. While knowledge of the sources, impact and potential solutions for some air pollutants already exists, there are some research gaps.

The report identifies gaps in understanding how certain pollutants are generated, transformed and interact with the

human body, and in designing countermeasures and mitigations – this includes the health effects of different components of PM, a better understanding of indoor air pollution, and economic analyses of air pollution interventions. Further development is also needed in counter measures including tyre design and research on energy-efficient and heat-retaining building ventilation.
Dr Sarah Clarke, president of the Royal College of Physicians (RCP), said:
“Air pollution is a growing and significant public health challenge and we strongly welcome the Chief Medical Officer making this the focus of his annual report for 2022.
“The RCP has been highlighting the harmful impacts of air pollution on health since 2016, when we published our report Every Breath We Take with the Royal College of Paediatrics and
Child Health. We estimated then that around 40,000 deaths were attributable to outdoor air pollution, and since then a coroner found it to be a cause of death for the first time, that of 9-year-old Ella Adoo Kissi Debrah.
“The CMO’s report is an important contribution that makes clear why we must be proactive and ambitious in our efforts to improve both outdoor and indoor air quality for everyone.”