Air Pollution Mortality Benefits of Sustained COVID-19 Mobility Restrictions in Australian Cities

Background: Emissions from road traffic, power generation and industry were substantially reduced during pandemic lockdown periods globally. Thus, we analysed reductions in traffic-related air pollution in Australian capital cities during March–April 2020 and then modelled the mortality benefits that could be realised if similar reductions were sustained by structural policy interventions.Methods: Satellite-based observations were used to estimate ground-level nitrogen dioxide (NO2) concentrations in all Australian capital cities during: (a) a typical year with no prolonged air pollution events; (b) a hypothetical sustained reduction in NO2 equivalent to the COVID-19 lockdowns. We use the WHO recommended NO2 exposure-response coefficient for mortality (1.023, 95% CI: 1.008–1.037, per 10 μg/m3 annual average) to assess gains in life expectancy and population wide years of life from reduced exposure to traffic-related air pollution.Findings: Although COVID-19 related reductions in NO2 varied widely between Australian cities during April 2020, 3348 years of life would be gained annually if those reductions were maintained.Interpretation: COVID-19 lockdowns in Australian cities indicate the potential for reductions in NO2 exposures from behavioural policies that reduce emissions from internal combustion engines. We measured the effect on mortality if the change was sustained over decades following reductions in internal combustion engines.Funding: The HEAL (Healthy Environments And Lives) National Research Network receives funding from the NHMRC Special Initiative in Human Health and Environmental Change (Grant No. 2008937), and the Centre for Safe Air receives funding from NHMRC (Grant No. 2015584).Declaration of Interest: All of the authors declare no competing interests relating to the submission.