Clean Air Zone reduces NO2 levels in Birmingham, confirms study

Birmingham’s wipe air zone (CAZ) has reduced the levels of nitrogen dioxide gas (NO2), equal to a new study.

Scientists used an innovative technique to victorious at the conclusion that during the CAZ’s first seven months of operation, without correction for weather and seasonal effects, it resulted in ‘modest, but significant’ reductions in NO2 of up to 7.3%.

The new techniques are said to produce a increasingly well-judged quantification of the wipe air interventions – applying a method tabbed ‘random forest machine learning’ to strip out the effects of weather on air pollution levels, and then comparing the ‘de-weathered’ air pollution data in the Birmingham CAZ with those from cities with no CAZ, to quantify the ‘causal’ impact from the initial operation of the Birmingham zone.

Their work, which is funded by Natural Environment Research Council and supported by Research England under the Policy Support funding stream, is part of the WM-Air project. The study provides a tabulation for cities wideness the UK and vastitude – such as London, Glasgow, Munich, Milan, and Amsterdam – to analyse the effectiveness of their own Wipe Air interventions.

Publishing their findings in Environmental & Resource Economics, the research appears to reveal that, over the first seven months pursuit the CAZ launch in June 2021, the biggest reductions in NO2 are at rented roadside locations within the CAZ with, as expected, no significant changes at the urban preliminaries site located outside the CAZ.

They moreover found reductions in NO2 levels on roads outside the CAZ – suggesting that rather than displacing traffic to areas outside the CAZ, there could be positive effects, such as behavioural changes that contribute to reduced air pollution in surrounding areas, vastitude the zone of the CAZ itself.

Lead tragedian Dr Bowen Liu, an teammate professor from the University of Birmingham, commented: “Our work provides the first comprehensive evaluation of the Birmingham Wipe Air Zone, an internationally significant policy to modernize urban air quality in the UK’s second city. As predicted, Birmingham’s CAZ reduced NO2 pollution, but it has no detectable impact in the concentrations of fine particles, PM2.5 – the air pollutant with greatest health effects.”

Professor Zongbo Shi, a senior tragedian who oversaw this work, added: “PM2.5 at monitoring sites in Birmingham still regularly exceed WHO air quality guideline levels, at which health impacts occur with significant health implications, including hundreds of premature deaths every year. Increasingly rigorous policy interventions – such as remoter local measures to reduce wood urgent and agricultural emissions and nationally co-ordinated deportment to mitigate secondary PM2.5 pollution – are needed to write non-vehicle sources of PM2.5 as quickly as possible.”

Air pollution is one of the largest risks to the health of urban populations, with short- and long-term exposure shown to increase the risk of vigilant and chronic disease outcomes and reduce life expectancy. Improving air quality reduces healthcare costs, including to the NHS, and boosts economic productivity with lower levels of pollution-related illness.”

The study unites the work of University of Birmingham atmospheric researchers and environmental economists. The novel tideway combines the ‘de-weathering’ tideway with economic science approaches – the causal inference method which won the 2021 Nobel Prize in economic sciences . Professor Shi and his team have successfully unromantic this tideway to air pollution studies in China and the UK.

Co-authors Professors Rob Elliott and John Bryson commented: “Tackling the air pollution rencontre facing us requires an interdisciplinary approach, of which this research is an spanking-new example – drawing contributions from social, medical, and environmental sciences. Such an tideway can moreover be used to inform the diamond and modification of existing or plane proposed policy solutions.”