One in five cases of asthma in kids could be linked to traffic pollution, according to new research.
Globally, that means four million children develop asthma every year as a result of air pollution from vehicles, that’s the equivalent of 11,000 new cases a day.
Nitrogen dioxide, which comes from vehicle exhausts, has been described as a “substantial” risk factor for the condition, meaning busy cities are not good for lung health.
The research was published in the journal of Lancet Planetary Health and is the first global assessment of the impact traffic fumes has on childhood asthma.
Their work suggests that 29% of new childhood cases in London can be blamed on nitrogen dioxide pollution – While in Manchester, the figure is at 23%.
Out of the 194 countries studied, the UK had the 24th highest new cases of childhood asthma that could be blamed on traffic pollution.
However, South Korea topped the chart, with nearly a third of new cases linked to car fumes.
It is thought that pollution from traffic makes it harder to breathe because it’s bad for children’s airways. This means that if asthma runs in someone’s family they’re more likely to get symptoms in areas where there are lots of vehicles.
One of the scientists involved in the research, Dr Ploy Achakulwisut, from the George Washington University, in America says that in countries where governments have tried to reduce traffic pollution they have seen an improvement in the breathing health of children.
In Shenzhen in China, they have electrified their entire bus service, while in London has created a Ultra-Low Emission Zone.
What is asthma?
Asthma affects the small airways that carry air in and out of your lungs. From time to time, the muscles surrounding these airways constricts after becoming irritated by inflammation.
The airways are narrowed further as the amount of mucus lining the airways increases and sufferers may wheeze and struggle to draw a full breath.
Episodes can last from between an hour to weeks if left without treatment.
Asthma is a chronic condition, which means attacks can occur throughout your life. However, whilst there are times when severe episodes strike, for most asthmatics there are long periods during which they have few, if any, symptoms.
It can affect anyone at any age, but it tends to be worse in children and young adults.
What causes asthma?
While asthma is caused by an inflammation of the airways, scientists don’t know exactly what causes this inflammation. Asthmatic and allergic tendencies run in families and scientists believe there are a number of different genes that react with environmental factors to trigger the onset of asthma.
Whilst scientists are searching for the genes involved, they do already know that there are a number of things that could increase the risk of developing the condition.
- Exposure to allergens (proteins which can cause an allergic reaction) during pregnancy – from foods in the mother’s diet, for example
- Being brought up in a house where there is a pet, especially a cat
- Having certain illnesses as a child
- Being exposed to cigarette smoke in the womb or early life – babies whose mothers smoke are twice as likely to develop asthma
- Having allergies to things such as pollen, house-dust mites and mould
- Contributing factors in the Western world include air pollution and processed foods
What can cause an asthma attack?
Once you have asthma, there are a number of triggers known to cause a flare up, known as an asthma attack. These triggers vary from person to person, but include: weather conditions; certain medications; exposure to chemicals and traffic fumes; foods; exercise; strong emotions; and infections. Smoking and exposure to second-hand smoke is particularly dangerous for asthmatics.