Air quality: Commission refers PORTUGAL to the Court of Justice of the European Union for high levels of nitrogen dioxide

Source: European Commission (EC) i, published on Friday, November 12 2021.

Today, the Commission has decided to refer Portugal to the Court of Justice of the European Union over poor air quality caused by high levels of nitrogen dioxide. When the limit values set by the EU's ambient air quality legislation are exceeded (Directive 2008/50/EC), Member States are required to adopt air quality plans to ensure that appropriate measures are taken to keep the duration of the exceedance period as short as possible.

The European Green Deal and the Zero Pollution Action Plan emphasise the importance of cutting air pollution, which is among the key factors negatively affecting human health. Full implementation of the air quality standards enshrined in EU legislation is key to effectively protect human health and safeguard the natural environment.

Portugal has continually and persistently exceeded the annual nitrogen dioxide limit value in three air quality zones (‘Lisboa Norte', ‘Porto Litoral', and ‘Entre Douro e Minho'). Air pollution from nitrogen dioxide in these air quality zones results mostly from road traffic, in particular from diesel vehicles. Portugal has also failed to adopt appropriate measures to keep the exceedance period as short as possible.

The Commission sent a Letter of Formal Notice to Portugal on air quality in May 2019, followed by a Reasoned Opinion in February 2020. The Commission therefore considers that efforts by the Portuguese authorities have to date been unsatisfactory and insufficient, and is referring Portugal to the Court of Justice of the European Union.


Member States must ensure good air quality for their citizens. However, air pollution remains a problem in many places, with the situation being particularly serious in urban areas. EU legislation on ambient air leaves to the Member States the choice of measures to comply with the limit values set by the legislation.

Air pollution remains the number one environmental health problem in the EU. According to estimates of the European Environment Agency, around 400 000 premature deaths can be attributed to air pollution each year in the EU. Related to nitrogen dioxide (NO2) specifically, estimates point to almost 50 000 premature deaths in the EU each year.

The air pollutant nitrogen dioxide (NO2) results mostly from human activities, such as road traffic, in particular diesel vehicles, and industry. This type of pollution is the cause of serious illnesses such as asthma and reduced lung function.

For More Information

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