nitrogen dioxide

Child asthma cases linked to cities’ dirty air

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  • Nitrogen dioxide (NO2) pollution is the cause of 1.85 million child asthma cases a year – study
  • NO2 pollution is increasing in Sub-Saharan Africa, South Asia
  • Air pollution reduction must be integrated into child health policies, say researchers.
asthma cambodia

A child in Cambodia getting asthma treatment using an inhaler. A study has highlighted rising nitrogen dioxide pollution levels as a leading cause of child asthma in urban areas in South Asia and Sub-Saharan Africa.

Reducing air pollution should be a crucial part of health strategies for children, as nitrogen dioxide (NO2) — a harmful pollutant emitted from burning fossil fuels — may lead to nearly 2 million new child asthma cases a year, research suggests.

The study, published this month in The Lancet Planetary Health, highlights rising NO2 pollution levels in urban areas in South Asia and Sub-Saharan Africa, where it suggests child asthma is a serious health concern.

Researchers from George Washington University in the US say it is the first study to estimate the global burden of asthma cases in children resulting from NO2 emissions in more than 13,000 cities.

“The findings suggest that clean air must be a critical part of strategies aimed at keeping children healthy.”

Susan Anenberg, professor of environmental and occupational health, George Washington University

“Our study found that nitrogen dioxide puts children at risk of developing asthma and the problem is especially acute in urban areas,” said Susan Anenberg, study co-author and a professor of environmental and occupational health at the university, in Washington DC.

Asthma affects around 262 million people worldwide, according to the 2019 Global Burden of Disease study, and is the most common chronic disease among children, causing inflammation of the lung’s airways.

However, reliable data is still lacking on the condition. Most asthma-related deaths occur in low- and middle-income countries where it is often under-diagnosed and under-treated, according to the World Health Organization.

NO2 is formed by the burning of fossil fuels such as oil and gas and is mainly emitted by vehicles, industry, agricultural machinery, and power plants.

By analysing ground concentration of NO2 and new cases of asthma in children from 2000 to 2019, researchers observed that, in 2019, an estimated 1.85 million new cases of childhood asthma were attributable to NO2 worldwide, and two thirds of these cases (1.22 million) were in urban areas.

NO2 pollution has been increasing in South Asia, Sub-Saharan Africa, and the Middle East, the researchers found, while air quality has shown improvements in Europe and the US.

Explaining the connection between NO2 and childhood asthma, the researchers said: “NO2 itself has been associated with adverse health outcomes including asthma exacerbation. Epidemiological studies have also found associations between transportation-related air pollutants [such as NO2] and new onset asthma in children.”

According to the researchers, some studies indicated that pollutants such as NO2 cause inflammation and changes in airways due to oxidative stress, sometimes resulting in asthma.

“The findings suggest that clean air must be a critical part of strategies aimed at keeping children healthy,” said Anenberg.

A review published in 2019 in the journal Environment International highlights possible measures to combat NO2 pollution, such as “a ventilation strategy with suitable filters…ventilating windows or intakes; traffic planning (location and density); and reducing the use of NO2-releasing indoor sources.”

Stanley Szefler, director of the Pediatric Asthma Research Program at the Breathing Institute of Children’s Hospital Colorado, US, who was not involved in the Washington DC study, told SciDev.Net: “The report by Anenberg and colleagues reinforces the role of air pollution on paediatric asthma incidence and supports the role of public health and environmental control stakeholders…to speak for clean air measures.

“Furthermore, the report suggests that monitoring environmental levels of nitric dioxide could serve as a surrogate marker [an indicator of a disease state] for regions of high risk for increased childhood asthma incidence as well as an indicator of the efficacy of mitigation measures for air pollution.”

Szefler was the lead author of a study published in 2020 in the journal Pediatric Pulmonology. It advocated for “a worldwide charter” on child asthma that would act as a roadmap for “better education and training”.

“The charter indicated that asthma guidelines alone are insufficient and need supplementing by government support, changes in policy, access to diagnosis and effective therapy for all children, with research to improve implementation,” Szefler added.

Sushmita Roychowdhury, director of pulmonology at Fortis Hospital, in Kolkata, India, says that paediatric asthma is becoming more common in highly populated cities.

“Children living in high-rises close to the main busy arterial roads are found to have more symptoms early on,” she said. “Most children in urban India waiting for school buses in the morning or those taking public transport are exposed to high concentrations of pollutants.”

German Carmakers Exposed Monkeys And Humans to Diesel Fumes in Secret Tests

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Everyone is outraged.
 

Controversy has erupted after reports revealed German carmakers have collaborated on experiments in which monkeys and human participants were intentionally exposed to toxic diesel fumes.

 The secret experiments, which took place in both the US and Germany, were part of a ‘clean diesel’ research initiative funded by Volkswagen, the world’s largest automaker, with BMW and Daimler. Public outcry over the revelations has been swift.

“These tests on monkeys or even humans are in no way ethically justified,” said Steffen Seibert, spokesperson for German Chancellor Angela Merkel. “The indignation felt by many people is completely understandable.” The story broke after a report in The New York Times detailed a previously unknown 2014 experiment commissioned by the European Research Group on Environment and Health in the Transport Sector (EUGT) – a now-disbanded research institution funded by the three carmakers. Among other studies it oversaw, EUGT chose the Lovelace Respiratory Research Institute in Albuquerque, New Mexico, to conduct an experiment that might ostensibly show how harmless diesel fumes were: by forcing a group of monkeys to inhale diesel exhaust for 4 hours. The animals, 10 cynomolgus macaque monkeys, bred exclusively for medical experiments, were held in chambers into which exhaust fumes from a Volkswagen Beetle running on a treadmill was directly pumped.

 To keep the animals calm and occupied during the experiment, lab workers had set up a TV the animals could view from their gas chambers.

“They like to watch cartoons,” one of the Lovelace researchers, Jake McDonald, said in a sworn deposition last year in a lawsuit brought against Volkswagen in the US by Volkswagen diesel owners. What McDonald and the other researchers didn’t know at the time, though, was that the whole experiment was actually a sham. The Beetle they’d been supplied with was part of the ‘dieselgate’ emissions cheating scandal uncovered in 2015 – in which some 11 million VW cars around the world were fitted with illegal ‘defeat devices’ capable of masking levels of toxic nitrogen dioxide pollution pumped out by the car’s exhaust. When the cars detected they were being examined for emissions testing purposes, pollution controls throttled back the nitrogen dioxide output – whereas in regular use on the road, the engines would output diesel fumes at levels that breach emissions standards. What this means is, in the 2014 experiment, the monkeys thankfully weren’t getting a full blast – not that they had it easy.

 In a separate, comparative test, they also had to inhale fumes produced by an older-model 1999 Ford diesel pickup – before being anaesthetised and intubated, then having their lungs washed out so their bronchial tubes could be examined.

In a statement on Saturday, Volkswagen said it “distances itself clearly from all forms of animal abuse”, but that was before German media produced new reports of similar experiments involving human participants. These tests, conducted by Aachen University in Germany in 2013 and 2014, and also commissioned by the EUGT, saw 25 young healthy adults inhale varying concentrations of nitrogen dioxide for several hours each. While it appears the university secured ethics approval to conduct the research – in addition to written consent from all those who took part – it’s just another black mark against the carmakers implicated in the diesel emissions scandal, especially with what we know about how bad nitrogen dioxide is for us. “Vile,” is how German environment minister Barbara Hendricks described the revealed experiments. “That a whole branch of industry has apparently tried to discard scientific facts with such brazen and dubious methods makes the entire thing even more horrific.”