Study: Traffic pollution linked to rise in asthma

Researchers have found a link between polluted air and increased cases of asthma among children.

The study that was published in The Lancet found a correlation between exposure to nitrogen dioxide (NO2) and asthma in children.

As nations celebrate, today, the World Environment Day, whose theme is “Beat Air Pollution”, the United Nations says it is incumbent on leaders to take measures to improve air quality.

The study notes that global paediatric asthma prevalence has increased since the 1950s, putting the respiratory disease as the most commonly reported non-communicable disease globally.

In Kenya, respiratory diseases, among them asthma, are the leading cause of hospital visits, according to the 2018 Economic Survey report.

In 2016, there were 19 million hospital visits for respiratory illnesses. The numbers dropped to 14 million in 2017. According to Kenyatta National Hospital, up to 4 million Kenyans suffer from some sort of respiratory disease.

Fossil fuels

Nitrogen oxide is one of the by-products formed when fossil fuels like coal and petroleum are burnt at high temperatures. When breathed in, it can cause inflammation of the lungs and the airwaves, which leads to nasal congestion and wheezing.

In the April 2019 study sponsored by George Washington University, North America, Latin America, Europe and East Asia reported associations between traffic-related air pollution (TRAP) exposure and new-onset asthma in children.

However, such associations were found to be less clear in adults.

“Corroborating evidence from toxicological and gene-environment studies have suggested that TRAP causes oxidative injury to the airways, leading to inflammation and re-modelling that, in a genetically predisposed individual, could result in asthma development,” the report states.

The study noted that although the presumed agent in traffic air pollution cannot be identified, the only correct relation is nitrogen dioxide because it can be measured and is also found in polluted traffic air.

“Despite the accumulating epidemiological evidence, the burden of paediatric asthma incidence attributable to TRAP exposure remains poorly quantified and has not been included in previous global burden of disease studies,” reads the study.

Of the regions surveyed, the largest percentage of paediatric asthma incidence attributable to nitrogen oxide pollution was estimated for high-income Asia Pacific, followed by East Asia and high-income North America, southern Latin America, and Western Europe.

“Eastern sub-Saharan Africa was estimated to have the lowest incidences of new asthma cases attributable to NO2 exposure per 100,000 children,” the study reads. These are, on average, 150 cases in every 100,000 population of children.

A 2017 study by Eco Experts ranked Kenya among the countries with less toxic air globally. Other nations were Mozambique, Ethiopia, Tanzania and Zimbabwe.

According to the United Nations, polluted air kills up to 7 million people each year globally from diseases such as asthma. Deaths and illnesses from air pollution are caused by tiny particles that penetrate the lungs every time people take a breath. 

“These particles come from many sources: The burning of fossil fuels for power and transport; the chemicals and mining industries; the open burning of waste; the burning of forests and fields; and the use of dirty indoor cooking and heating fuels, which are major problems in the developing world,” said UN Secretary General António Guterres.  

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