September 22, 2020

The economic revival causes a rebound in pollution in the Canary Islands – La Provincia

The cleanest skies in the containment were intended to be covered again with soot, nitrogen dioxide (NO2), and hydrocarbons (HC). In the Canary Islands, the low levels of contamination that had been registered during the period of confinement have risen again, although not yet reaching previous levels. However, this is related to the lower mobility of the population due to vacations, the closing of schools and telework that still prevails in public administrations.

For example, in the García Escámez neighborhood in Santa Cruz, when we were forced to stay home, an average of 3 microns per cubic meter of NO2 was recorded in the air. This particle arises from the combustion of gasoline in vehicles and is the one that most accurately reflects “the daily activity of cities.” After phase 2, which began on May 25, these levels have been increasing until reaching an average of 10 microns per cubic meter. A higher figure, however, which still contrasts with the average concentration of this pollutant in February 2020, which stood at 18 microns per cubic meter of NO2.

As the physicist at the Izaña Atmospheric Research Center, Emilio Cuevas, points out, the current data does not reflect the “normality” of the air quality in the city, so they are not comparable with the period of confinement. “We cannot know yet what repercussions our stoppage of activity has had,” explains Cuevas, who points out that, in order to determine if the Covid-19 has had any impact on the quality of Canary air, it will be necessary to study it further when the summer and both schools and workers recover the rhythm of life that prevailed before the state of alarm.

In any case, both Cuevas and the researcher of the Higher Council for Scientific Research (CSIC), Sergio Rodríguez, assure that this increase in harmful particles in the air after the end of the state of alarm is framed within expectations. “The conclusion is that we need a different economic and social model,” insists Rodríguez. And his diagnosis is ratified by Cuevas, who, for his part, insists that “if there is no change in policy, things will hardly change.” The example is in the city of Barcelona that has taken advantage of the confinement to expand the network of available bicycles.

In this way, the population is allowed to move without having to use their private vehicle while avoiding exposure to contagion on public transport. “That is a change that can last over time,” insists Cuevas. In the Canary Islands, however, no such action has been taken.

Nitrogen dioxide was the pollutant that decreased the most during confinement, since it is closely linked to mobility. In heavily polluted cities, such as Madrid and Barcelona, ​​the reduction was between 60 and 70%. In Santa Cruz de Tenerife, during confinement, the concentrations of nitrogen dioxide in the air that its citizens breathed were reduced by 80%. In the center of Gran Canaria, this decrease in harmful particles emitted by vehicles was 60%. When the Government of Pedro Sánchez decreed the progressive lack of control, NO2 emissions rose again. However, decreeing it just at the beginning of the summer, has allowed the possible rebound effect that some Spanish researchers had warned – what would happen in a scenario in which the vehicles left at the same time after the end of the confinement -, has been mitigated .

An experiment

“It was an experiment that we could not have carried out in any other way,” says the atmospheric physicist from Izaña, who points out that, as soon as some research project is funded, they will be able to begin a more exhaustive work on how the confinement affected to the air quality in the Islands. “It will be done,” says Cuevas with conviction and highlights that it will probably start after the summer, since it will be when the “normal” activity is expected to reactivate. Cuevas, however, is aware of the uncertainty of the course of the pandemic.

For this reason, he insists that we will have to keep waiting to see how events unfold in the coming months, since at the end of the year, under a new epidemic wave, citizens could confine themselves again. In this study, “different variables must be taken into account”. “It is not just looking at the data,” insisted the scientist, who stressed that the comparison should be made between different years and taking into account the meteorological situations that have occurred in each period.

Because the weather in the Canary Islands has a lot to do with its pollution levels. In fact, in recent days -with the intrusion of Saharan air and the haze that came associated with it-, pollution by nitrogen dioxide has reached unprecedented rates in the course of this year.

The explanation is that, when the haze is deposited in the upper areas of the atmosphere – very common during the summer – it acts as a “stopper” and locks the pollutants in a smaller space, also increasing its concentration close to the city . In Santa Cruz de Tenerife it is where this increase has been most noticed because the Anaga mountain range protects it “from the trade winds”, Sergio Rodríguez points out, the natural mechanism that the Archipelago has to “ventilate” its municipalities.

More than 10,000 deaths a year

According to the Spanish Society of Pneumology and Thoracic Surgery (Separ), air pollution causes 10,000 deaths a year in Spain. In the air we breathe there is not a single pollutant, “the air quality is modulated by various external agents at the local level,” recalls expert Sergio Rodríguez. By level of harmfulness, there would be soot first. These particles are emitted by burning diesel, and have been found to have implications for the development of cancers. The main emitters are vehicles but also by cruise ships that, when they arrive at port, continue to emit polluting gases into the atmosphere in large concentrations.

These large vessels, which remain for days on Avenida de Anaga in Santa Cruz de Tenerife, are also responsible for other major pollutants in cities: sulfur dioxide (SO2) and hydrocarbons (HC). And the dangerous thing is that, when they unite in the atmosphere, they create ultrafine particles – less than 0.1 micron per cubic meter – that we inhale when breathing and that are related to the development of heart disease. The last two pollutants in cities are nitrogen oxides and ozone (O3). Ozone is not emitted directly into cities, but it is deposited on them as a consequence of the chemical reactions that take place when nitrogen dioxide, carbon monoxide and hydrocarbons are in the atmosphere.

The decrease in pollution in cities has not only been an unprecedented experiment and impossible to carry out under other conditions; It has also been a wake-up call for citizens. If anything has been proven after this small concession to the environment, it is that humanity is still far from being able to face its next great challenge: climate change. “Despite this decline in pollution levels in many cities and despite the world stopping its engines for months,” the Covid-19 has not affected the concentration of gases such as carbon dioxide (CO2) in the atmosphere “recalls the geographer and researcher of the Chair of Disaster Risk Reduction and Resilient Cities of the University of La Laguna (ULL), Abel López. In fact, on April 18, the Izaña Global Atmospheric Surveillance Observatory, dependent on the State Meteorological Agency (Aemet), confirmed that 418.7 parts per million (ppm) of daily average concentration of this gas in the global atmosphere had been reached.

A new record in a historical series that has been growing steadily for four decades. “Globally, C02 emissions reductions are expected to be around 7% this year and it is this reduction that we should maintain for years to meet the objectives set in the Paris Agreement,” confirms López, who insists in which, above all, “this drop in emissions will not stop effects on climate change.” In recent years, the Canary Islands has suffered some phenomena that may be related to global warming, although not directly, as also geographer of the Chair of Disaster Risk Reduction and Resilient Cities of the ULL, Pedro Dorta points out. The Delta, the floods of Santa Cruz, the sea attack of Garachico, the fires of Gran Canaria in the summer of 2019 or the super-heat of February could occur more often with climate change, and, so far, what has been evidenced the occurrence of these phenomena is that we are not prepared.

“Most of the disasters to which the Archipelago has been subjected in recent years have more to do with poor land management than with climate change,” says Dorta, who indicates that “the responsibility is ours.” Hence, researchers see only one way out for the Archipelago: to adapt to the new climatic conditions that the world is going to suffer. “The battle of mitigation is lost,” says Dorta, who insists that, not for this reason, the reduction of polluting gas emissions should be avoided, but rather act to “prepare ourselves for what we are going to live; because it will be very serious”.


Source link