How has the UK lockdown affected air pollution in Birmingham?

Cllr Waseem Zaffar, Cabinet Member for Transport and the Environment, looks at the impact of the UK lockdown on air pollution levels in Birmingham’s City Centre.

In my blog post last week I mentioned that we had been closely monitoring traffic levels since the UK went on lockdown in response to Covid-19. Currently, traffic levels are around 30% of ‘normal’ levels. You can follow me on Twitter to find out more about this.

As a Council, we are obligated by the Joint Air Quality Unit to monitor air quality and air pollution levels. It would make sense that with such a significant reduction in traffic during the month of April, we would also see a reduction in air pollution levels following the lockdown.

The graph below details the weekly average pollutant concentrations from three city centre air pollution monitoring sites and shows the levels pre-lockdown, the reduction arising from the lockdown, and the continuing downward trend.

Pollutant concentrations for April in previous years tend to be higher than we are experiencing in 2020. There was a national pollution episode from the 8th to 14th April, which appears to have coincided with a slight increase in concentrations, following which the downward trend has resumed.

It’s worth remembering that there are a number of factors which influence pollution levels, especially the weather. However, a basic analysis of the data suggests an average reduction in pollution concentration (nitrogen dioxide) of approximately 36%.

For me, this provides further evidence that our current plans to reduce pollution in Birmingham are robust. Last month we made a decision to delay the launch of our Clean Air Zone, in order to give businesses and citizens more time to recover from the pandemic and plan for the changes. However, this decision does not mean that improving air quality in Birmingham is any less important. After all, when the pandemic is over, air quality will still be the biggest public health concern this city faces.

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