The European Environment Agency’s (EEA) data has confirmed large decreases in air pollutant concentrations — of nitrogen dioxide (NO2) concentrations in particular — largely due to reduced traffic and other activities, especially in major cities under lockdown measures. Reductions of around half have been seen in some locations.
The EEA’s data are measured hourly, on the ground, at about 3,000 monitoring stations across European countries.
The EEA has received many questions about the impacts of the stark measures to limit the spread of the coronavirus (COVID-19) on air quality in Europe.
The EEA’s data for recent weeks show how concentrations of nitrogen dioxide (NO2), a pollutant mainly emitted by road transport, have decreased in many Italian cities. For example:
- In Milan, average concentrations of NO2 for the past four weeks have been at least 24 % lower than four weeks earlier this year. The average concentration during the week of 16-22 March was 21 % lower than for the same week in 2019.
- In Bergamo, there has been a constant decline in NO2 pollution over the past four weeks. The average concentration during the week of 16-22 March was 47 % lower than for the same week in 2019.
- In Rome, average NO2 concentrations for the past four weeks were 26-35 % lower than for the same weeks in 2019.
Similar trends can be seen in other European cities where lockdown measures have been implemented during the week of 16-22 March.
- In Barcelona, average NO2 levels went down by 40 % from one week to the next. Compared with the same week in 2019, the reduction was 55 %.
- In Madrid, average NO2 levels went down by 56 % from one week to the next. Compared with the same week in 2019, the reduction was 41 %.
- In Lisbon, average NO2 levels went down by 40 % from one week to the next. Compared with the same week in 2019, the reduction was 51 %.
The weekly average concentration levels of air pollutants were calculated based on data from the EEA’s up-to-date air quality data system. All daily mean values from the stations in each city have been considered for the average. Other factors than the lockdown measures, such as weather conditions, can also have an effect on weekly variations of the pollutant concentrations.
The EEA monitors Europe’s air quality through a network of more than 4,000 local air pollution measurement stations across Europe. Most of the stations, managed by the EEA’s member countries in the European Environment Information and Observation Network (Eionet), record hourly data on key air pollutant concentrations and send it to the EEA.