Legacy of coal still burning issue 60 years on
A study, presented at the European Respiratory Society’s International Congress in London from 3-7 September, was the first to look at the long term impact of exposure during childhood, and shows that exposure to coal-based pollution experienced over 60 years ago is still putting people at greater risk of dying today.
The study, which was released as part of the Healthy Lungs for Life campaign, looks at the impact of pollution from domestic coal use (black smoke (BS) and sulphur dioxide (SO2)) and shows people are almost twice as likely to die from a respiratory condition if they were living in the most polluted areas as a child in the 1950s compared to the least polluted areas.
After allowing for socioeconomic differences, mortality from respiratory diseases was more than twice as high in urban areas with the highest coal usage (0.7 tons per acre or more), including Manchester, Middlesbrough and Nottingham, compared with those with the lowest usage (less than 0.2 tons per acre), like Bath, Canterbury and Exeter.
The findings are echoed by a second longitudinal study being presented at the Congress by a team from Imperial College London, which demonstrates a similar long-term impact of exposure to a range of pollutants (BS, SO2 and particulate matter with a diameter less than 10 µm (PM10)) on respiratory mortality, that also takes into account migration and changes in air pollution exposure over time.
The study, which analysed data for 368,000 individuals from England and Wales followed over a 38 year period, shows that exposure to BS in 1971 was associated with a 5% increased risk in respiratory mortality per 10 µg/m3 in 2002-2009, jumping to 8% for COPD specifically. The data underline the impact of air pollution on diseases such as COPD, which is now the 5th biggest killer in the UK.
While the Clean Air Act has led to a reduction in black smoke and sulphur dioxide emissions, largely through increased use of cleaner fuels, levels of nitrogen oxides and small particles (e.g PM10) from transport pollution have increased and become the dominant sources of atmospheric pollution in urban areas. The ERS is using their annual International Congress to call for more research into how all types of air pollution affect health over a person’s lifetime.
Soaring pollution levels directly reduce lung function
As alarming as the long term risks to the lungs are, we also now understand more about the short term effects. A third study due to be presented at the ERS Congress by a team from the Flemish Institute for Technological Research (VITO) compared air quality monitoring with the results of repeated, yearly lung function testing in a cohort of 2,449 healthy adults over a 4-year period. The results show that higher exposure on the day and the day before the lung function testing can lead to a direct – and immediate –decreased lung function.
According to the results, there is an average reduction in lung function of 0.5% with every 10 µg/m³ increase in PM10 and a 0.2% reduction with every 1 µg/m³ increase in nitrogen dioxide (NO2). With levels ranging from 5 to 130 µg/m³ and from 5 to 65 µg/m³ for PM10 and NO2 respectively, the potential impact could be considerable.
While there have been increasing efforts to raise awareness of the risks of air pollution to at risk groups, the study shows a clear impact of pollution on healthy individuals as well.
Commenting on the new research, Professor Stephen Holgate, ERS Science Council Chair said: “There is an enduring health legacy from the large amounts of coal used in this country well into the 20th century. Not only do these findings have important implications for countries like China and India that still depend on coal, but they should be a wake-up call to our own government to take air pollution from all sources more seriously. We have a ticking time-bomb on our hands”.
Commenting on the studies, Professor Jørgen Vestbo, President of ERS and Professor of Respiratory Medicine at the University of Manchester, said:
“If there’s one clear takeaway from this research it’s that the air we breathe – today, tomorrow, yesterday – matters. While we can’t change historic exposure, we can act now to reduce pollution levels and improve health outcomes in the future. Everyone needs to be aware of what it is, where it is and the harm it can cause.”