Higher air pollution days are triggering strokes, cardiac arrest, and severe asthma attacks in adults and children

An additional 124 out-of-hospital cardiac arrests, 231 hospitalizations for stroke and 193 hospitalizations for asthma can be caused on days when pollution levels are high, shows analysis of 9 UK cities


                            Higher air pollution days are triggering strokes, cardiac arrest, and severe asthma attacks in adults and children

Hundreds of children and adults are suffering from out-of-hospital cardiac arrests or being sent to the hospital for strokes or severe asthma attacks on days when air pollution levels are higher. The analysis - which examined nine major cities across England, including Birmingham, Bristol, Derby, London, Liverpool, Manchester, Nottingham, Oxford, and Southampton - states that overall, higher air pollution days trigger an additional 124 out-of-hospital cardiac arrests, 231 hospitalizations for strokes and 193 children and adults' hospital admissions for asthma. 

The findings by King's College, London, is the interim report of a larger study - personalizing the health impacts of air pollution - which is scheduled to be published in November 2019. 

"The impact of air pollution on our health has been crucial in justifying air pollution reduction policies for some time and mostly concentrates on effects connected to life-expectancy. However, health studies show clear links with a much wider range of health effects. This project provides short statements of fact, backed up by supporting evidence," says Dr Heather Walton, senior lecturer of environmental health from King's College.

According to the researchers, typical statements about the impact of air pollution on health have been communicated in terms of numbers of premature deaths or life years lost. “This is mainly because it is assumed that people are most concerned about the most severe endpoints and these usually have a dominant influence on cost-benefit analysis. Most places collect mortality statistics routinely, there are a lot more studies for this end-point. Further, there are also more studies on all-cause mortality because it is a clearly defined endpoint without confusion as to whether a disease has been diagnosed correctly,” says the team.

Hence, the aim of the project is to develop statements on the effects of air pollution on health outcomes that may be "more familiar" to people than life years, life expectancy, or numbers of deaths. 

Impact of air pollution on adults and children.

Out-of-hospital cardiac arrests and strokes

The risk of out-of-hospital cardiac arrest ranged from 1.8% to 2.4% across the nine cities. The risk of cardiac arrest in London, for example, is 2.2% higher on high air pollution days than lower air pollution days. The researchers say that each year, on average, higher air pollution days in London are responsible for 87 more cardiac arrests outside the hospital than lower air pollution days. 

The risk of out-of-hospital cardiac arrest ranged from 1.8% to 2.4% across the nine cities studied.
(Getty Images)

"Out-of-hospital cardiac arrests refer to people whose hearts have stopped when they are not in the hospital but are either at home or out in the street. Some but not all survive and are admitted to the hospital," the researchers explain.

The other cities would see around 2 to 12 cardiac arrests - Southampton (2), Nottingham (3), Bristol (4), Liverpool (4), Oxford (6), Manchester (6), and Birmingham (12). As far as strokes are concerned, the risk of emergency hospitalizations for stroke in Birmingham, says the report, is 2.6% higher on high air pollution days than on lower air pollution days. The researchers say that lowering air pollution by 32.1% on high air pollution days in Birmingham could save 27 hospital admissions for stroke each year. 

"Living near a busy road in Birmingham increases your risk of hospitalization for stroke by 4%. Based on the difference between the middle of the range of daily average nitrogen dioxide levels at roadsides and the middle of the range of daily average nitrogen dioxide levels away from roads. Nitrogen dioxide may be acting as a marker for other traffic pollutants. On high air pollution days in Birmingham, there are on average 27 more hospital admissions for
stroke each year than on lower air pollution days," the findings state.

Similarly, in London, there are, on average, 144 more hospital admissions on high air pollution days for stroke each year than on lower air pollution days. Reducing air pollution by 22% on high air pollution days could prevent these hospitalizations. 

Asthma admissions & reduced lung growth in children

Higher air pollution days could also trigger severe asthma attacks in adults and children, shows analysis. In children, more pollution could mean that a child is anywhere between 4.1% to 6.2% more likely to be hospitalized for asthma across the cities studied. The percentage varies between 1.2% to 2.1% for adults in these nine cities. 

Children were also more likely to experience asthma symptoms on high air pollution days than on lower pollution days.

A child is anywhere between 4.1% to 6.2% more likely to be hospitalized for asthma on higher pollution days. (Getty Images)

Some of the other long-term risks of high pollution include reduced lung growth and low lung function. In Manchester, for example, cutting air pollution by one fifth would increase children's lung capacity by around 2.6%. Reducing air pollution by one fifth would also result in 284 fewer children with low lung function each year, say the researchers.

Roadside air pollution, found the team, stunts lung growth in children by 14.1% in Oxford, 12.5% in London, 7.7% in Birmingham, 5.3% in Bristol, 4.6% in Liverpool, 3.8% in Southampton, and 2.8% in Nottingham.

Yet another long-term adverse impact of pollution, says the team, is low birth weight among children. Living near busy roads may contribute to a higher risk of babies being born underweight - this ranges from 0.1% in Liverpool, Southampton and Nottingham to 0.2% in Birmingham and Bristol, and 0.4% greater risk in London.

"As these new figures show, air pollution is now causing thousands of strokes, cardiac arrests, and asthma attacks, so it's clear that the climate emergency is, in fact, also a health emergency," says Simon Stevens, chief executive of NHS England. 

"Since these avoidable deaths are happening now - not in 2025 or 2050 - together we need to act now. For the NHS, that is going to mean further comprehensive action building on the reduction of our carbon footprint of one fifth in the past decade. So our NHS energy use, supply chain, building adaptations, and our transport will all need to change substantially," adds Stevens.

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