As we wrote before in our article about how Covid-19 is reducing pollution in Portugal, according to data from the European Space Agency, the average levels of nitrogen dioxide in Lisbon, emitted mainly by road vehicles, dropped 40% in only one week during the confinement.
In Avenida da Liberdade, the busiest avenue in the Portuguese capital, pollution decreased by nearly 60%. The pollution levels registered were far behind those registered in the same period of 2019 and these are the lowest pollution levels of the past 7 years, according to a study from the FCT/NOVA University.
The CENSE (Centre for Research in Environment and Sustainability, from this institution), evaluated concentrations of nitrogen dioxide in five air quality monitoring stations in Lisbon, managed by the Lisbon and Vale do Tejo Regional Coordination and Development Commission, in 10 workdays (from 16 to 27 of March). In this period, they found out that in Restelo (an area of the city with better air quality), the reduction in pollution was of 21%, of 56% in Avenida da Liberdade and 58% in Entrecampos.
They also concluded that, like the European Space Agency data revealed, the nitrogen dioxide levels on workdays on Avenida da Liberdade were 60% below the annual average of 2019 – 23mg per cubic meter, which is nearly half of the usual 40 mg/m3.
A professor from CENSE stated that NO2 and inhalable particles are the pollutants that have higher concentrations in cities like Lisbon, mainly due to vehicles that use diesel as a fuel. Apart from road traffic, he also highlighted that the decrease in airplane and cruise ships traffic has contributed to these lower pollution levels in the capital.
The study mentioned above also concluded, right in the first week of restrictions, that the concentrations of air pollutants in Avenida da Liberdade had already decreased 15% and in Entrecampos and Olivais 25%.
Several sources have been making clear that the environment was one of the sole beneficiaries of the confinement due to Covid-19. Now, already in a deconfinement period, the environmental association Zero disclosed some data which showed that the levels of pollution in Avenida da Liberdade are the lowest of the century and that, in this period, were not identified in the air about 44 atmospheric pollutants that are normally present in the area.
Zero also concluded that, in Lisbon, in the first workdays of deconfinement, the medium concentration of NO2 was lower in all monitoring stations than in the period between the state of alert and the end of the state of emergency.
Despite our strong desire to get back to normal life as soon as possible, all this makes us reflect on the importance to take measures to control the worrying pollution levels, especially in big cities.