Transport and public health

The World Health Organization (WHO) recently warned of health-threatening air pollution levels in major cities around the world. Just days into 2016, several European cities including London and Paris were affected by pollution episodes. Citizens were invited to change their behaviour by using public transport networks or car sharing in order to prevent the problem from worsening. Given specific meteorological conditions coupled with high pollutant emissions and projected extreme heat events linked to climate change, we can expect pollution episodes to become more frequent.

There is clear and increasing evidence of the health impacts that exposure to a whole range of air pollutants can have. Although only episodes of high pollution might be making the newspaper headlines, long-term and continued exposure to even low concentrations of air pollutants is much more harmful to human health.

The European transport sector has achieved significant reductions in the emissions of certain major air pollutants — mainly due to the introduction of emissions standards, financial measures and, to a lesser extent, alternative-fuels and transport avoidance measures. But more work is needed to continue to reduce pollution levels and meet European Union targets for 2030 and beyond. And, although it is the biggest culprit, it is not only the road transport sector that needs to reduce emissions — air, shipping and rail also contribute to air pollution and must not be ignored.

Similarly, noise pollution threatens human health and wellbeing, with road traffic again the most widespread contributor. While there have been reductions in air pollutants from transport, exposure to noise levels above accepted limit values has remained constant across European urban areas in recent years.

Health impacts of transport

The most recent figures for Europe show that, despite considerable emissions reductions in the last decade, more than 400 000 premature deaths^[1] per year can be attributed to air pollution from all sources.

Individual air pollutants can cause a variety of health impacts. Nitrogen oxides, particulate matter (PM₁₀ and PM_2.5), sulphur oxides, carbon monoxide, and various heavy metals such as cadmium, lead and mercury are all emitted from the exhausts of vehicles. In addition, precursor chemicals in exhausts may react in the atmosphere giving rise to the formation of ozone. Finally, particulate matter and heavy metals are also released into the air as a result of tyre and brake abrasion and, once they have been deposited on the pavement may be ‘re-suspended’ in the air by passing cars.

Exposure to these pollutants can have very specific health impacts, but in general, the organs, nervous system and blood are affected, causing or aggravating ailments such as lung disease — leading to respiratory problems — heart attacks, asthma, anxiety, dizziness and fatigue.^[2]

Noise also has significant health impacts. Exposure during the night can cause sleep disturbance, leading to adverse health effects. Long-term exposure during an average day period can result in increased blood pressure and cardiovascular disease among other illnesses. As many as 80 % of Europeans are expected to be living in urban areas by 2020, with a large number of these near busy transport infrastructure and hubs such as airports and motorways.

An estimated 125 million Europeans (or one in four) are affected by noise levels from road traffic that exceed an average annual day, evening and night level of 55 decibels (55 dB L_den). Due to incomplete reporting, these numbers are likely significantly higher.

Measuring annoyance from noise

L_den is a descriptor of noise level based on an energy equivalent noise level averaged over a whole day. It is designed to assess annoyance. The Environmental Noise Directive sets L_den at 55 dB for noise mapping assessments and action planning. For assessing sleep disturbance in an exposed population, the directive recommends the application of an L_night indicator, with a threshold of 50 dB.

Recent figures suggest that such exposure leads to 20 million Europeans experiencing annoyance from noise, as well as 8 million suffering sleep disturbance, 43 000 hospital admissions and at least 10 000 premature deaths. In addition, noise from aircraft movements in and around airports affects a considerable number of people, including school children — at least 8 000 of whom suffer reading impairment in Europe as a result of exposure to high noise levels.

Tackling air and noise pollution

Current European transport, air quality and noise legislation deals with air pollution and environmental noise, with a view to improving human health and the environment. European emissions standards (Euro standards) regulate emissions of pollutants from different types of vehicles. For example, the current Euro 6 standard, in force for new vehicles since 2014, sets emissions limits of particulate matter from petrol and diesel cars at 5 milligrams per kilometre (mg/km), a fivefold reduction compared to 2005 levels. Similarly, NO_x emissions limits are set at 80 mg/km for diesel cars and 60 mg/km for petrol cars, again, marking a considerable reduction since 2005.

Euro standards include specifications for vehicle testing but there are significant differences between official vehicle emissions (i.e. those recorded under test conditions) and real-world emissions. Measures are being taken to rectify this, including the development of new test specifications and the roll-out of Portable Emissions Measurement Systems (PEMS), which can be fitted to cars to measure on-road conditions.

To reduce harm from noise pollution, the EU has put in place different measures, including technical standards to limit noise emissions at source (e.g. EU tyre labelling to help consumers identify ‘quieter’ tyres). The Environmental Noise Directive complements such standards. It aims to improve the quality of data collected with a view to better managing the relationship between residents and traffic. The directive requires action plans to be drawn up for major transport sources and the largest urban areas, the aim of which is to reduce the impact of noise on the affected population — and reduce noise itself if necessary — as well as to protect quiet areas, i.e. those areas free from noise pollution. These action plans are currently in a third five year cycle, running until 2018.

In parallel with EU efforts, many local and regional initiatives are looking for innovative solutions to transport-related air pollution and noise problems. The ‘Ljubljana Step-by-Step Approach’ and Seville’s Big Bang’,^[3] which ran between 2006 and 2013, are two such initiatives that favour cycling infrastructure development. Both have successfully reduced traffic congestion, improved air quality and lowered GHG emissions. In Seville, while the number of daily car journeys into the town centre dropped from 25 000 to 10 000 over the duration of the project, a 29 % drop in NO₂ and a 19.5 % drop in PM concentrations were measured. Meanwhile, in Ljubljana, the modal share of cycling as a proportion of total traffic rose by 20 % during the project. These figures indicate impressive results. Regarding improvements in health or noise reduction, there are no official data, although anecdotal evidence suggests noise levels dropped significantly in both towns.

Looking at the future

Given these legislative frameworks and innovative solutions, emissions of air pollutants from transport are expected to continue their decline across Europe, with positive impacts on human health. However, 87‒90 % of city dwellers in the EU are still exposed to levels of air pollutants deemed harmful by the WHO. In fact, by meeting these levels for PM_2.5, it is estimated that some 144 000 premature deaths could be avoided. In the longer-term, Europe will need to further integrate policy measures and actions to reduce air pollutant emissions and create the conditions for better health and wellbeing of European citizens, and avoid the effects of pollution episodes such as those in London and Paris. Reducing pollutant emissions from transport could certainly help improve air quality, in urban areas in particular.

The situation for noise is even more challenging. Noise is a pervasive pollutant in Europe and continued economic growth, increased industrial output, expanding urbanisation and related transport needs will continue to threaten the quality of Europe’s soundscape. This will have an impact on the health of Europeans. Noise from road traffic will remain the biggest threat, while noise from airport activities will continue to affect those living nearby. Improved noise reporting is essential to build a more complete picture of the health impacts it brings about. Countries are encouraged to continue to develop their noise action plans, but the focus should also be on noise reduction at source — a far more efficient way of solving the problem.

Footnotes