Third of childhood asthma cases preventable by tackling air pollution

Scientists estimate that up to 33% of new childhood asthma cases could be prevented every year if European countries met tougher PM2.5 guidelines than what the World Health Organisation (WHO) suggests.

The study, published in the European Respiratory Journal, also said that countries who meet WHO guidelines could cut 11% of annual cases.

Currently, the WHO guidelines indicate an annual mean limit for PM2.5 is 10 μg/m3, whereas the EU’s is 25μg/m3.

However, several European countries regularly exceed the higher EU limit.

To come up with the figures, researchers from the Barcelona Institute for Global Health (ISGlobal) used census population data from 18 European countries and looked at incidence rates of asthma in children from the Global Burden of Disease (GBD) study database.

Exposure to the different pollutants was calculated using a harmonised European statistical model based on multiple measurements in Europe.

To then estimate the burden of childhood asthma, researchers posed two different scenarios: the first one was based on the maximum air pollution levels recommended by the World Health Organisation (WHO) air quality guidelines.

The second scenario took as a reference the lowest air pollution levels recorded among 41 previous studies.

However, the study co-authors suggested that WHO guidelines for nitrogen dioxide (NO2) may be too low, warning if countries met them only 0.4% of asthma cases would be prevented.

Study co-author David Rojas-Rueda said: ‘Our estimations show that the current NO2 WHO air quality guideline value seems to provide much less protection than the PM2.5 guideline. We suggest that these values require update and lowering to be better suited in protecting children’s health.’

Responding to the study, Dr Penny Woods, chief executive of the British Lung Foundation, said: ‘The fact that the air in our towns and cities could be giving children a lifelong and potentially life-threatening illness is disgusting and simply unacceptable.

‘We also know air pollution can cause exacerbations – a flare up of symptoms – for people already living with asthma and other lung conditions, potentially leaving them in need of hospital treatment.

‘It’s clear that now is the time for truly bold action, not vague, barely-there policies.’

In one of his final acts as Environment Secretary, Michael Gove said the UK’s upcoming Environment Bill will enshrine World Health Organisation (WHO) limits for PM2.5 in UK law.

The WHO has previously said that this lower limit for PM2.5 could reduce pollution-related deaths by around 15%.

The 18 European countries covered in the study are Austria, Belgium, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Lithuania, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the UK.

In other related news, a study released last week found fine particulate matter (PM2.5) can send the body’s immune system into overdrive by over-activating a natural defence mechanism, worsening asthma symptoms.

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