Traffic pollution linked to new child asthma cases

Traffic-related air pollution may result in asthma development.

Nitrogen dioxide (NO2) pollution appears to be a substantial risk factor for childhood asthma incidence in both developed and developing countries, especially in urban areas, the findings in "The Lancet Planetary Health" journal shows. The US (240,000), Indonesia (160,000) and Brazil (140,000) had the next largest burdens.

Traffic-related air pollution is associated with four million new cases of childhood asthma worldwide every year, according to the first global estimates of the problem.

The UK ranked 24th worst out of 194 countries, with China 19th and the U.S. 25th.

India ranks below other countries for this metric because although levels of other pollutants (particularly PM2.5) in the country are among the highest in the world, NO2 levels (between 2010 and 2012) in Indian cities appear to be lower than or comparable with European and USA cities, the researchers said.

"Improving access to cleaner forms of transportation, like electric public transport and active commuting by cycling and walking, would not only lower NO2 levels but would also reduce asthma, enhance physical fitness and cut greenhouse gas emissions", Annenberg said.

"Examples include Shenzhen's electrification of its entire bus fleet and London's Ultra-Low Emission Zone congestion charges".

Globally, asthma is the most common non-communicable disease among children and prevalence has increased dramatically since the 1950s. The reasons for this are multiple.

While it is not clear which pollutant in traffic air pollution is responsible, previous research has suggested exposure to nitrogen dioxide is key.

A Scottish Government spokesperson said: "Compared to the rest of the United Kingdom and other parts of Europe, Scotland enjoys a high level of air quality and we have set more stringent air quality targets".