Cleaner air for Scotland: the road to a healthier future

A strategy setting out the Scottish Government's proposals for delivering further improvements to air quality.

5. Health

A Scotland which protects its citizens from the harmful effects of air pollution, reducing health inequalities.

Health today – the health impacts of air pollution

5.1 There is now no question that air pollution is bad for our health. The impacts first became clear last century following studies of the effect of industrial pollution associated with heavy industry. The infamous London smogs of the 1950s provided clear evidence of an association between increased deaths in urban areas and episodes of severe pollution from industrial and domestic coal fires. These sources have been addressed to a large extent and are no longer the main issue. However, evidence of the effects of exposure to air pollutants, especially from traffic, continues to accumulate.

5.2 Air pollution is less visible today and its effects on health are less obvious to the general public, which makes it harder to convince people that it is still a public health problem. Air pollution does not cause dramatic, distinctive illnesses in the same way that, for example, smoking tobacco causes lung cancer. Instead, it contributes to a range of other factors (personal, social and environmental) all of which increase the risks of common diseases (for example asthma, respiratory and heart disease), especially in people who are more vulnerable due to age (the very young and the elderly) or existing health conditions. This results in:

  • increased episodes of acute and chronic (long-term) illness;
  • reduced life expectancy (premature death);
  • more pressure on health services (for example, increased use of medications, increased visits to GPs, increased hospital admissions);
  • higher consequent costs; and
  • loss of work time and school time.

5.3 Although short-term peaks in levels of urban air pollution are generally lower now than in the past, effects on health can still be identified; for example increased death rates due to heart disease a day or more after elevated pollution [34] .

5.4 However, there is now a substantial body of international evidence demonstrating not only peaks, but also background levels of air pollution that have an impact on everyone’s health. In 2010, the Committee on the Medical Effects of Air Pollutants ( COMEAP) estimated that in the UK increased background levels of fine particulate matter ( PM 2.5) raised the overall risk of death and reduced life expectancy [35] . In Scotland this equates to the cumulative equivalent of about 2,000 deaths per year across the whole population, significantly more than the number of fatal accidents on Scottish roads [36] . There is increasing evidence of the effects on health of PM 2.5 at progressively lower concentrations; even lower than 5 µg/m 3. Recently published updated estimates of the mortality attributable to particulate matter in the air (at the PM 2.5 size fraction) in Scotland based on COMEAP methods [37] , indicate that the impact varies across local authority areas depending on the average PM 2.5 levels [38] .

5.5 During the 2013 European Year of Air, WHO reviewed the most recent evidence on the chronic impacts of air pollution and found overwhelming evidence of the impact on mortality and morbidity, including cardiovascular and respiratory disease, birth outcomes and neurological effects [39] . There is, therefore, no currently identified safe threshold for concentrations of PM, emphasising the need to continue efforts to reduce background levels.

5.6 More recent international research [40] looking at roadside air pollution suggests stronger links with coronary heart disease, deaths and illness associated with closer proximity to roads. Modelled estimates also suggest that these effects may worsen with an ageing population.

5.7 The WHO International Agency for Research on Cancer [41] concluded that particulate matter from diesel engine exhausts can be classified as carcinogenic to humans. Also identified was an increasing risk of lung cancer with increasing levels of exposure to particulate matter [42] .

5.8 Research on the effects of air pollution on health has mainly focused on particulate matter, especially fine particulate matter ( PM 10 and PM 2.5). However, evidence is beginning to accumulate on the potential scale of impacts associated with nitrogen oxides ( NOx), especially nitrogen dioxide ( NO 2), either on its own or in combination with other pollutants. COMEAP produced an updated review of the evidence relating to NO 2 and concluded that on balance, NO 2 is responsible for some of the impacts on health identified in epidemiological studies on air pollution and health to date [43] . This is particularly important, in view of the current concerns regarding the levels of NO 2 now associated with diesel powered vehicles. COMEAP is now developing estimates of the impact of these emissions on mortality [44] .

5.9 A review of the current evidence on traffic-related air pollution has recently been completed as part of a project funded by the Scottish Government to identify the key messages on air pollution and health in Scotland [45] . The report identified limited but increasing evidence of the benefits of good air quality. A study from 2015 demonstrated that exposure to lower levels of particulate pollution (in United States of America nurses) was associated with lower levels of anxiety [46] . Other studies have demonstrated that improved self-reported wellbeing is associated with lower levels of air pollution [47] .

5.10 Some sources of air pollution cannot be easily controlled locally due to their transboundary nature, but traffic related air pollution is a major source that can be reduced through local and regional action. Therefore, it makes sense to continue with efforts to:

  • reduce peak levels of air pollution especially in local communities (for example, by considering the introduction of access control options, such as Low Emission Zones or Clean Air Zones, as outlined in Table 4, following the stages outlined in Section 11); and
  • drive down background levels of preventable air pollution.

5.11 There is no doubt that air pollution has negative impacts on health [48] and the evidence of good air quality improving wellbeing is accumulating (Figure 9). Reducing levels of air pollution, especially from transport, will have positive impacts on health and lessen health inequalities. This will also reduce the cost burden on health and other services. Strategies to encourage people to consider the travel hierarchy outlined in Section 6 will have positive health co-benefits helping to tackle other chronic public health problems, such as those associated with a sedentary lifestyle.

Figure 9. Air quality links to health

Figure 9. Air quality links to health [49] [50] [51] [52]

Health tomorrow – what more do we need to do?

5.12 Changing personal behaviour to improve health is always a challenging task. Evidence [53] indicates that to make people appreciate the significance of the issue, they need to be given information that helps them understand what individual air pollutants do to them physically (see case study 1). People also need personalised information on air pollution in their local environment, to complement more general information. However, simply raising concerns about air pollution and health without providing any solutions or practical alternatives to enable personal change, is likely to be counterproductive and result in a negative, resigned attitude to the issues. Case study 2 provides an example of how to provide a simple message to the general public and businesses so that they can make a personal contribution to cleaner air.

5.13 It is essential, therefore, to get the messages right about air pollution and health and provide accurate information to people. However, urging individuals to change their own habits for the wider benefit of the population or the environment will not be enough. Communication aimed at encouraging behavioural change needs to take account not only of individual personal factors that determine people’s habits (personal circumstances, beliefs and preferences) but also wider issues such as:

  • their social context (social norms and expectations, such as the social acceptability of driving a car); and
  • material issues that constrain and shape people’s behaviour (for example, the transport infrastructure, the availability of practical alternatives to car travel, and the costs of change) [54] .

5.14 Providing personalised and targeted individual information to help people develop a personal travel plan with practical alternatives to car travel can work [55] .

5.15 Local agencies working together, especially local authorities and local NHS boards, have a significant role to play in supporting the aims of CAFS by encouraging behaviour change to improve health and reduce health inequalities in local communities. Guidance is available at the local level to help agencies identify ways to raise the profile of air pollution and health and develop local action plans [56] .

5.16 One option to raise the profile of air pollution in Scotland is to make use of the existing framework for joint planning on health protection. The Public Health Etc. (Scotland) Act 2008 requires each Health Board, in partnership with the local authorities in its area, to prepare a joint health protection plan. These plans provide an overview of the priorities, provision and preparedness for health protection (in relation to communicable disease and environmental health). Incorporating a section specifically about air quality and health, making use of available local data on the impacts to health (such as the estimated mortality attributable to PM pollution) would be one way to:

  • highlight the issues locally [57] ;
  • set out agreed plans to promote the provision of local information about air quality; and
  • link to other local initiatives (for example, encouraging active travel).

We will:

Require NHS boards and their local authority partners to include reference to air quality and health in the next revision of their joint health protection plans, which should identify and address specific local priority issues

5.17 Also recognising the need for action at national level, the Scottish Government will focus on setting health-based objectives for air quality to reflect the growing evidence that health effects can be identified even at relatively low levels of air pollution.

5.18 An increasing body of evidence suggests that fine particulate matter ( PM 2.5) is the most significant fraction of particulate pollution in terms of health impacts. The WHO has set guideline PM 10 and PM 2.5 values of 20 µg/m 3 and 10 µg/m 3 respectively as annual means [58] . These values are considerably more stringent than the equivalent EU and UK targets, but similar to the Scottish objectives of 18 µg/m 3 and 12 µg/m 3. Following the review of the Local Air Quality Management system (see paragraph 4.2 for more information), the Scottish Government has decided to replace the existing Scottish objectives with the WHO guideline values. Whilst this is undoubtedly a positive step, the approach will create challenges, with respect to the transboundary impacts on PM 2.5 in particular.

We will:

Include in legislation as Scottish objectives World Health Organization ( WHO) guideline values for PM 10 and PM 2.5

Case study 1

Improving public awareness of air quality impact on health – British Heart Foundation

Air pollution can make existing heart conditions worse and cause cardiovascular events in vulnerable groups. Since 2010 the British Heart Foundation ( BHF) has provided £6.9 million for medical research to help better understand the link between air pollution and cardiovascular disease. However in February 2015 a survey of general public awareness of air quality issues by the BHF revealed the following:

  • Only 20% were aware of a risk of
    stroke due to poor air quality.
  • 49% of Scots were unaware of the risk of heart disease from air pollution.
  • 58% of Scots did not know what the local air quality was in their area, or where to go to find this information.

These statistics clearly showed the need for a wide reaching communications campaign to inform and equip the public on the dangers of air pollution and the actions they can take to reduce their exposure. In response to this need the BHF provided an online information sheet on how air quality affects the heart, who is most at risk, what individuals can do, and where to go for further information. The BHF also tweets about episodes of high air pollution when they occur and is strongly supportive of the Scottish Government’s commitment to ensure that people across Scotland are aware of the importance of air quality.

Case study 2

Switch Off and Breathe – West Lothian, East Lothian, Midlothian and Falkirk Councils

In 2007 the East Central Scotland Vehicle Emissions Partnership ( VEP) – a partnership of four Scottish local authorities – launched a campaign to help reduce vehicle emissions through educating the general public by the provision of vehicle emissions testing, free to the public and supported by Scottish Government funding, and encouraging drivers to switch off their engine whenever possible. VEP actively deals with reports from members of the public who identify vehicles which are excessively smoky and also stationary vehicles which idle their engines for long periods.

The emission testing service allows drivers to check emissions from their vehicles, without penalty, to ensure that they will pass the MOT test and comply with legal requirements. It also helps to ensure that people are not breathing unnecessary noxious fumes created by vehicles.

To publicise its messages and to try and change driving habits across the country, VEP makes extensive use of local radio, television and newspaper advertising, along with a website

The campaign highlights the health benefits of reducing pollution levels to both prevent and alleviate illnesses such as asthma and heart and lung conditions.


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