Indoor air pollution and relevance for the NHS - Professor Nicola Carslaw, University of York

Context

In developed countries such as the UK, it has been estimated that we spend around 85-90% of our time indoors, including in our homes, at work and commuting between the two. However, with the exception of occupational exposures, regulation around air pollution exposure focuses almost entirely on outdoor air pollution. If we want to fully understand our exposure to air pollution and then make sound suggestions on how to reduce it, we need to consider indoor air pollution as well as that from outdoors.

Indoor air pollution

Some of the pollution we are exposed to indoors comes from outdoors, for instance through open windows and doors. If a residence or workplace is on a busy road, the traffic could be a major source of indoor air pollutants. Indoor sources include activites such as cooking, fuel burning on open fires or inefficient/poorly-maintained stoves, cleaning, DIY activities, smoking and use of persnoal care products and air fresheners.

There are also sources of pollution from furnishings and building materials, as well as bio-effluents (e.g. carbon dioxide) from people. Finally, chemical and physical interactions between pollutants and building surfaces can make further pollutants. The indoor air quality in a building will therefore depend on its location, how it is ventilated (natural or mechanical) and what activities are going on inside it.

The drive to increase energy efficiency through increased insulation in recent years, has led to increasingly airtight buildings and species emitted indoors take longer to be diluted and removed. It is vital that indoor sources are considered as well as those outdoors when trying to understand the overall exposure (and consequent health effects) of an individual. Otherwise, by trying to avoid one source of pollution, you may inadvertently expose an individual to higher pollutant concentrations.

An obvious example might be shutting the windows of a residence to avoid traffic exhaust from cars outside, but then being exposed to undiluted cigarette smoke being generated by a smoker indoors. Smoking is well known to cause adverse health effects, but some of the activities mentioned above can also generate harmful pollutants. For instance, cleaning and cooking can lead to the production of particulate matter and the use of fragranced products can produce formaldehyde, both of which are associated with adverse health effects.

Relevance for the NHS

There are two main issues for the NHS when it comes to indoor air pollution. The first is around those presenting with conditions that are exacerbated by exposure to air pollution. In this case, a health care specialist might reasonably suggest that the individual avoids exposure to polluted areas such as adjacent to busy roads, or avoids exercise outdoors when outdoor pollution is high. This would only be good advice if the indoor environments used by that individual are known to be free of sources of pollution that also worsen their condition. Adverse health outcomes have been shown to increase as ventilation decreases, so shutting the window is not always a good solution without understanding all of the sources an individual is exposed to.

The second issue is around the healthcare environments themselves. An obvious step would be to avoid fragranced products (e.g. cleaning products) in these settings, and also, thinking about the time of day when cleaning is carried out. Indoor chemistry (and hence the processes that drive production of harmful secondary products) tends to be driven by outdoor ozone, which is higher in the afternoons, especially in summer. Cleaning in the morning could therefore lead to lower concentrations of some pollutants indoors than if cleaning were carried out in the afternoon. The appropriateness of some of the air cleaning devices that are marketed to remove bio-pathogens should also be considered. Whilst some of these may be effective, others are less so and some use chemical reactions internally that can cause harmful products to be emitted upon use. As these devices are largely unregulated at the moment, it is important to understand the full impacts of any instrument used in a healthcare setting, both chemically and biologically.

What can be done?

There are several things that can be done to lower exposure to indoor pollutants in any setting. Avoid unnecessary personal care product use, use cream products instead of spray products and use a cooker hood (that ventilates outdoors) while cooking. Ventilate regularly with outdoor air if it is relatively clean: if you live near a road, use a window on the other side of the building. In summer, if outdoor ozone is high and windows are open to keep a building cool, consider avoiding cleaning activities until outdoor ozone is lower.

Further Reading

The US-EPA site on indoor air quality provides some excellent background information on indoor air quality www.epa.gov/indoor-air-quality-iaq

Read about the WHO air quality guidelines for indoor air pollutants: www.euro.who.int/en/health-topics/environment-and-health/air-quality/publications/2010/who-guidelines-for-indoor-air-quality-selected-pollutants

This paper reviews indoor chemistry: Weschler CJ, Carslaw N (2018) Indoor Chemistry. Environmental Science and Technology 52: 2419–2428. doi: 10.1021/acs.est.7b06387

And this one presents a review of data around adverse health effects and lower ventilation rates: Sundell, J., Levin, H., Nazaroff, W.W., Cain, W.S., Fisk, W.J., Grimsrud, D.T., Gyntelberg, F., Li, Y., Persily, A.K., Pickering, A.C., Samet, J.M., Spengler, J.D., Taylor, S.T. and Weschler, C.J. (2011) Ventilation rates and health: multidisciplinary review of the scientific literature, Indoor Air, 21, 191-204.

Content provided by Professor Nicola Carslaw, University of York. For more information please email This email address is being protected from spambots. You need JavaScript enabled to view it..

Health impacts of air pollution in the UK - Professor Helen ApSimon - Imperial College London, and Dr Mike Holland - Imperial College & EMRC

Despite huge improvements since the intense pollution smogs of the 1950s, the impacts of air pollution on human health remain a major problem in the UK. Before the Clean Air Acts of 1956 and 1968, triggered by the Great London Smog of 1952, the main concerns were emissions of sulphur dioxide and particles from coal burning. These have fallen substantially given strict legislation and wide-spread switching from coal to gas, and more recently solar and wind energy. However there has been growth of other pollutants, in particular from traffic, and from emerging trends such as domestic wood burning.

Understanding of the health impacts of air pollution has grown substantially since the 1980s through the publication of a large literature on epidemiological research in the UK and many other countries. Early work linked mortality and respiratory hospital admissions to exposure to fine particles. This has since expanded to include a broader range of pollutants and effects. With respect to exposure to pollutants in the ambient air, most attention in the UK and Europe is now focused on three pollutants, fine particles (PM_2.5) which can penetrate deep into the lungs, nitrogen dioxide (NO₂), and ozone formed as a secondary pollutant from chemical reactions in the atmosphere. Although various suggestions have been made that some particles, such as those in diesel exhaust, could be more harmful than others, the particles present at any location are a combined mixture from multiple sources and relative toxicities have not been established.

Information from the epidemiolocal studies can be used to derive response functions that enable the impacts of exposure to be estimated when combined with data on pollutant concentrations and population. The UK’s Committee on the Medical Effects of Air Pollutants (COMEAP) has estimated the mortality burden of air pollution in the UK from exposure to fine particles PM_2.5 and nitrogen dioxide, NO₂, in 2013, indicating a mortality burden of between 328,000 and 416,000 years of life lost across the population every year. This translates to between 28,000 and 36,000 equivalent attributable deaths. A study by the Royal College of Physicians provides a higher estimate of 40,000 equivalent attributable deaths per year, but includes ozone as well as NO₂ and PM_2.5 (www.rcplondon.ac.uk/projects/outputs/every-breath-we-take-lifelong-impact-air-pollution). The RCP report highlighted a wide range of health impacts affecting all stages of human life from the womb to old age. These include links between air pollution and cancer, asthma, stroke and heart disease, diabetes, obesity and changes linked to dementia – all of them being illnesses of high concern for the NHS.

What is being done about it

Recognition of these problems has led to international and national steps to improve the situation; which is illustrated below by a map of annual average PM_2.5 concentrations in 2016, and indicates around 15 million people in the UK are exposed above the WHO standard of 10 micrograms per cubic metre (µg.m^-3). The worst areas in red are clearly correlated with cities and urban populations, where effects of local sources are superimposed on a background from national sources, long-range contributions imported from other countries and shipping, and including secondary particles formed by chemical reactions in the atmosphere. International action under the UNECE Air Convention and the European Commission has led to the setting of ceilings for emissions from each country to control the transboundary imported pollution including PM_2.5 and ozone. The distribution of nitrogen dioxide is even more concentrated in urban areas, but is mainly due to local sources, particularly traffic.

Annual average PM_2.5 concentrations in 2016 (UKIAM model) 

www.gov.uk/government/publications/air-quality-assessing-progress-towards-who-guideline-levels-of-pm25-in-the-uk

Reduction of air pollution at the national level is being addressed in Defra’s “Clean Air Strategy” as published in January 2019, and covering pollutant emissions from transport, at home, from farming and from industry (www.gov.uk/government/publications/clean-air-strategy-2019). An announcement by Michael Gove while still Environment Minister set a commitment to work towards attainment of the WHO standard of 10µg.m^-3 for PM_2.5, which is very much tighter than the current legal limit value of 25 µg.m^-3 set by EU legislation; and will require substantial reduction in emissions of both primary particles and gaseous precursors of secondary particles. Action at the city level is also focused on reducing pollution, particularly NO₂ concentrations; with measures like low emission zones and encouraging travel by walking, cycling or public transport. Changes in individual behaviour to help improve health are also needed to complement regulatory measures, and this requires wider awareness of the sources of air pollution and their consequences. It is also important to take a broader perspective, where for example the benefits of improved physical fitness from cycling or walking for short journeys can outweigh any disbenefits of exposure to air pollution, especially if there are suitable routes available. The medical profession can play an important role here in recognising connections between air pollution and health; and disseminating information to patients and the public.

The role of the NHS

As one of the world’s largest organisations (in terms of staff, behind only the US and Chinese military, McDonalds and Walmart), and costing the equivalent of around 6% of the UK’s GDP, it is not surprising that the NHS uses a significant quantity of energy for space and water heating, lighting and running equipment, and transport. For some years, the NHS Sustainable Development Unit (SDU) has investigated the carbon footprint of the health service. Recognising the NHS’ responsibility for health protection, SDU launched HOTT (Health Outcomes of Travel Tool) in 2017, which quantifies the health burden of air pollution and noise from transport linked to the NHS, along with accidents and greenhouse gas emissions. Version 3 of the tool has recently been released (www.sduhealth.org.uk/delivery/measure/health-outcomes-travel-tool.aspx). A future extension to HOTT will also quantify the air pollution impacts and GHG emissions of energy use by NHS Trusts.

HOTT provides analysis for NHS organisations at the level of individual CCGs, Ambulance Trusts and non-ambulance Providers such as hospital Foundation Trusts. The model uses up to date information on patient and staff numbers, travel distances, pollutant emissions and pollutant damage costs derived by Defra that cover the following outcomes for the two major transport pollutants:

• PM_2.5: mortality, respiratory and cardiovascular hospital admissions, stroke, chronic heart disease, asthma and productivity
• NO₂: mortality, respiratory hospital admissions, asthma, diabetes, productivity

As an illustration, results indicate 12.4 billion miles a year of travel linked to the activities of ambulance trusts, primary care and CCGs, and other providers in the NHS, with an associated estimate of health damage costs from air pollution of £162 million in 2018.

The HOTT tool allows users to develop their own future scenarios for transport provision, for example promotion of active travel, modal shift from cars to public transport and increasing the rate of electrification for the vehicle fleet, to see how these will affect future performance. Results can be used to assist in developing the business case for investment in cleaner and safer travel. There is also the potential for the NHS to use HOTT more widely, considering the travel burdens linked to other major organisations, such as universities, local authorities and private enterprises, and collaborating to increase the shift to more sustainable travel.

Content provided by Professor Helen ApSimon - Imperial College London, and Dr Mike Holland - Imperial College & EMRC

Why the Long Term Plan offers an opportunity for change in mental health - Geoff Heyes, Head of Health Policy and Influencing at Mind

In recent years leaders in the health and voluntary sectors have welcomed many mental health promises, from additional funding to innovative ideas for care in the community. But we should not underestimate the opportunity available now to change things at a national level and in communities for people living with mental health problems.

The publication of the NHS Long Term Plan was a mental health milestone, which recognised that mental health underpins almost all areas of health, and committed £2.3bn of ring-fenced funding a year for it. The plan is ambitious, including promises to support pregnant women and new mums, improve community care and increase people’s access to treatment like counselling and cognitive behavioural therapy. Importantly, it recognises the urgency of improving mental health services for children; many problems begin before the age of 18 and if younger people get the support they need, it can help to prevent more problems from becoming more acute.

The plan provides a huge opportunity to create the kind of mental healthcare most of us would want for ourselves and our families. We are now at the stage where this needs to be translated into reality at a local level.

The NHS recently published its mental health implementation framework - developed and tested with many of the same stakeholders as for the plan - setting out further detail for local areas on how the plan can be delivered. These local areas (Sustainability and Transformation Partnerships (STPs) and Integrated Care Systems (ICSs)) are now working up their own, detailed five-year plans.

At Mind, we expect this process to involve as many people with lived experience of mental health problems as possible, as well as experts in the sector, like local Mind branches, which are well placed to ensure the plans propose practical action to meet the community’s needs.

We know that in some parts of the country service users and those with first-hand experience of mental health problems are being included from the very start of the process. In Cornwall and the Isles of Scilly a wide-range of people including those who have used mental health services, young people, providers of services, and patient representatives, including Healthwatch, have helped to shape and influence its draft mental health strategy.

“We knew from the start that it was of critical importance to involve people with first hand experiences of using our services in the development of our plans. We would not be able to realise our vision, and deliver a plan that meets people’s needs without their involvement,” Dr Iain Chorlton, NHS Kernow’s chairman said.

NHS Kernow is now finalising plans to share Cornwall and the Isles of Scilly’s draft mental health strategy with the wider public to get their thoughts on its plan. What people say about the strategy will be used to update the draft strategy before its final submission by the end of the year.

This example shows what is possible and Mind will continue to hold to account those in power at a national and a local level, to ensure that a similar process takes place across the country and every promise is delivered. We should not underestimate the scale of the challenge in ensuring the money ear-marked for mental health reaches the frontline and that national policy is translated into meaningful local action.

Because, behind these promises and processes, and despite significant change particularly in the last five years, there is still much to do to improve in the experiences of people trying to access NHS mental health services. No one can deny that mental health is on the agenda like never before, in part proved by its profile in the Long Term Plan, but we are still feeling the effects of underfunding every day. We know that much of the time people only get help once they reach crisis point and, in total, fewer than four in ten people with a mental health problem get any kind of support at all.

As much as a lot is riding on these local plans to set the direction of travel for the coming five years, local decision makers must also not lose sight of the fact that we are in the middle of an existing five-year plan for mental health services. When Mind helped develop the Five-Year Forward View for Mental Health in 2016, we did it with an understanding that new plans take time to get going, which made 2019 a critical year for delivery.

On top of this, we also need to see a strategy which shows that the government will tackle the social issues often underlying poor mental health, like changes to the benefits system, poor quality housing, insecure employment, pressures in schools and a lack of social care.

People with mental health problems deserve better and only when we start to hear that people can get the support they need, when they need it, will we feel that we are making sufficient progress. Change is possible, but only with the full commitment and participation of the NHS and its partners from top to bottom. Proof of delivery will be in the experiences of people trying to access the services they need.

Content provided by Geoff Heyes, Head of Health Policy and Influencing at Mind. For more information please visit www.mind.org.uk.