News Release

More than 800 deaths may have been avoided due to air quality improvements during the first lockdown phase in Europe

Government actions linked to road travel had the greatest impact on lowering NO2 concentrations and reducing deaths

Peer-Reviewed Publication

London School of Hygiene & Tropical Medicine

Strict COVID-19 lockdown policies such as workplace closures in European cities reduced levels of air pollution and the number of associated deaths, according to new estimates published in Nature’s Scientific Reports.

The research, which was funded by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the Copernicus Atmosphere Monitoring Service (CAMS), was led by a team of statistical health and earth observation satellite modellers based at the London School of Hygiene & Tropical Medicine (LSHTM), with colleagues from CAMS.

The study compared government policies from 47 European cities from February to July 2020 and estimated the changes in pollution levels and related number of deaths avoided during the first wave of COVID-19 pandemic.

Government measures for COVID-19 such as school and workplace closure, cancelling public events, and stay-at-home requirements had the strongest effect on reducing NO2 levels. This is linked to the reduction in road transport and local mobility which is known to be a contributor to NO2 air pollution. Spanish, French and Italian cities had the largest decrease in NO2 of between 50% and 60% during the period.

Although strong decreases in NO2 were observed, levels of fine particulate matter PM2.5 and PM10 were reduced more modestly since they are also produced by natural sources (wildfires and dust), and other emission sources like residential activities, that were slightly increased during lockdown.

Antonio Gasparrini, Professor of Biostatistics and Epidemiology at LSHTM and senior author of the study, said: “The lockdown during the first wave of the COVID-19 pandemic created immense health and social costs, however, it has offered unique conditions to investigate potential effects of strict policies to reduce pollution levels in urban areas. This ’natural experiment’ has given us a glimpse of how air quality can be improved by drastic public health measures that would be difficult to implement in normal times. The information can be important to design effective policies to tackle the problem of pollution in our cities.

CAMS provided the surface-level data for this research using an ensemble of regional air quality models. This allowed the team to compare the concentrations of the main air pollutants with two emissions scenarios, one corresponding to business-as-usual conditions and the other corresponding to a detailed estimate of emissions resulting from the actual governmental measures taken during the first lockdown, varying for each country, each day and for each of the main activity sectors (road traffic, industry etc.).

Based on the estimates for NO2, there were 485.5 (confidence interval of 590.9; 377.6) excess deaths avoided associated with the exposure change (lockdown – business-as-usual difference), compared to 2,572.9 (confidence interval of 2,042.3; 3,070.9) excess deaths estimated under a business-as-usual scenario.

Across all pollutants, a total of more than 800 deaths were avoided with improved air quality resulting from the governmental measures taken to limit the spread of the SARS-Cov-2 virus. Paris, London, Barcelona, and Milan were among the top six cities with the highest number of avoided deaths.

Although all cities experienced a slight increase in air pollution levels after the strong decline in March and April 2020, levels remained below business-as-usual scenario estimates throughout the period studied. Restrictions on internal and international travel showed a minor impact on the local pollution levels.

Rochelle Schneider, Honorary Assistant Professor in Geospatial Data Science at LSHTM, Visiting Scientist at ECMWF, and first author of the study said: “Connecting expertise rapidly after and during the COVID-19 pandemic began has allowed us to estimate the health benefits from specific government measures. This, and other similar studies, can help drive the message that we definitely need to improve urban air quality for human health, and for the environment."

 “Government policies decided during the spring and early summer of 2020 gave us a unique opportunity to study a “real-life” scenario with lower air pollution levels. This paper conveyed strong messages on the potential of replicable, scalable, and collaborative research conducted with complementary expertise and knowledge from public health and tropical medicine universities, Copernicus, and meteorological institutes.”

Vincent-Henri Peuch, Director of the Copernicus Atmosphere Monitoring Service (CAMS), said: “This research benefits from a unique dataset provided by CAMS, which allows to compare as realistically and accurately as possible European air quality as it was experienced as a result of the COVID-19 measures and what would have happened under normal conditions. This overcomes many limitations of other studies, which compared for instance different years or different periods. The CAMS multi-model ensemble that has been used to generate this dataset has capabilities that have no equivalent in the world.”

Vincent-Henri Peuch added: “The findings are extremely significant as they consolidate the quantitative evidence that the COVID-related government measures had a direct effect on air pollution levels areas across Europe, particularly for NO2. Beyond the analysis of the mortality during the first months of the pandemic, this study could help shape future policy as the public health benefits of reducing pollution in our cities and the effectiveness of certain measures are clear to see”.

The authors acknowledge limitations of the study, including the use of country’s overall response rather than city-specific COVID-19 interventions.

The Copernicus Atmosphere Monitoring Service (CAMS) is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission with funding from the European Union.


For more information or interviews, please contact LSHTM Press Office at or Nuria Lopez at or +44 (0)7392 277 523. 

Embargoed copy of the paper available upon request.

Notes to Editors:

  • Air pollution in cities is made up of a mixture of gases (nitrogen dioxide [NO2], ozone [O3]) and particulate matter [PM2.5 and PM10]).
  • The CAMS regional air quality forecast system simulates the concentration of four pollutants under both scenarios during the same period and in identical weather conditions. The models not only account for the influence of weather variability, but also complex atmospheric processes and chemical interactions of multiple pollutants. CAMS consistently monitors air quality in Europe and around the world using satellite and ground-based observations with advanced numerical computer models and provides information in the context of the COVID-19 pandemic via a dedicated microsite.

Post-embargo access the report here: []

Differential Impact of Government Lockdown Policies on Reducing Air Pollution Levels and Related Mortality in Europe is published by Nature Scientific Reports [26.01.2022]

Contributors to the paper, led by the London School of Hygiene and Tropical Medicine and the ECMWF Copernicus Atmosphere Monitoring Service (CAMS) were: University of Bern; University of Florence; MRC Centre for Environment and Health; Royal Netherlands Meteorological Institute; Barcelona Supercomputing Centre; Italian National Agency for New Technologies Energy and Sustainable Development; Finish Meteorological Institute; A.M. Obukhov Institute for Atmospheric Physics; and France’s National Institute for Industrial Environment and Risks, and Météo-France.


The London School of Hygiene & Tropical Medicine (LSHTM) is a world-leading centre for research, postgraduate studies and continuing education in public and global health. LSHTM has a strong international presence with over 3,500 staff and 5,000 students working in the UK and countries around the world, and an annual research income of £180 million.

LSHTM is one of the highest-rated research institutions in the UK, is partnered with two MRC University Units in The Gambia and Uganda, and was named University of the Year in the Times Higher Education Awards 2016. Our mission is to improve health and health equity in the UK and worldwide; working in partnership to achieve excellence in public and global health research, education and translation of knowledge into policy and practice.

Follow @LSHTM on Twitter/Listen to LSHTM Viral Podcast.


About Copernicus and ECMWF

Copernicus is a component of the European Union’s space programme, with funding by the EU, and is its flagship Earth observation programme, which operates through six thematic services: Atmosphere, Marine, Land, Climate Change, Security and Emergency. It delivers freely accessible operational data and services providing users with reliable and up-to-date information related to our planet and its environment. The programme is coordinated and managed by the European Commission and implemented in partnership with the Member States, the European Space Agency (ESA), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the European Centre for Medium-Range Weather Forecasts (ECMWF), EU Agencies and Mercator Océan, amongst others.

ECMWF operates two services from the EU’s Copernicus Earth observation programme: the Copernicus Atmosphere Monitoring Service (CAMS) and the Copernicus Climate Change Service (C3S). They also contribute to the Copernicus Emergency Management Service (CEMS), which is implemented by the EU Joint Research Council (JRC). The European Centre for Medium-Range Weather Forecasts (ECMWF) is an independent intergovernmental organisation supported by 34 states. It is both a research institute and a 24/7 operational service, producing and disseminating numerical weather predictions to its Member States. This data is fully available to the national meteorological services in the Member States. The supercomputer facility (and associated data archive) at ECMWF is one of the largest of its type in Europe and Member States can use 25% of its capacity for their own purposes.

ECMWF has expanded its location across its Member States for some activities. In addition to an HQ in the UK and Computing Centre in Italy, offices with a focus on activities conducted in partnership with the EU, such as Copernicus, are in Bonn, Germany.

The Copernicus Atmosphere Monitoring Service website can be found at

The Copernicus Climate Change Service website can be found at

More information on Copernicus:

The ECMWF website can be found at






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