QCOSTARICA – Among the many anguishes that the pandemic has brought, there is encouraging news. The quality of the air breathed by residents, workers and visitors to downtown San José, has improved with the obligatory measures due to the health emergency.
The stay at home of thousands of people, in addition to the limitations to traffic, contributed to the 20% decrease in the concentration of nitrogen dioxide (NO₂) in the environment.
This polluting gas, which is emitted mainly by internal combustion engines, is harmful to human health. At extreme levels, it can cause acid rain.
The improvement is evidenced by the preliminary data of the latest study prepared by the Environmental Analysis Laboratory of the National University (UNA), which through passive air monitoring collects information in 28 different points of downtown San José.
According to the laboratory’s Víctor Hugo Beita, much of this improvement is related to changes in people’s mobility patterns, precisely caused by the coronavirus pandemic.
“The average annual concentration of this pollutant in the air was above approximately 37.6 micrograms per cubic meter. In 2020 that concentration decreased by about 20%.
“We have a reduction that is not negligible at all and that is closely related to vehicle emissions. This can be directly associated with the changes in mobility patterns that we have experienced and that we can reinforce in 2021.
“We cannot conclude it yet, because we are talking about data as of April this year, but, at least, in this first four months the behavior is very similar (to 2020),” said Beita.
Due to the dangers caused by the high presence of the pollutant, the World Health Organization (WHO) recommends that the concentration levels of this gas do not exceed the annual average of 40 micrograms per cubic meter (µg / m³).
However, the concentration of nitrogen dioxide in the Josefino (San Jose center) air exceeded that level for three consecutive years. This gas is one of the criteria that allow specialists to measure the level of air pollution.
During 2016, an annual average of 41.9 micrograms of nitrogen dioxide per cubic meter was recorded. A year later, the highest figure was reached, 48.1 µg / m³, while in 2018 the record was 41.4 µg / m³.
“It is a public health issue, of course. All these types of pollutants affect vulnerable people due to respiratory ailments, asthma or bronchial tube disease. This comes to intensify these sufferings,” said Beita.
Subsequently, in 2019, the rates once again fell below the WHO limit, with a significant decrease in the year of the pandemic, when 30.2 micrograms of NO₂ were recorded per cubic meter.
Preliminary data show that during the first four months of 2021, the concentration of the pollutant showed similar behavior to the previous year.
“The pandemic had an undeniable effect,” said Beita.
“How conclusive we can be at the annual data level (from 2021) would still be a bit risky to say, because we need to see what the behavior is during this second year,” said Beita.
However, the first evidence is encouraging, especially when considering the other devastating traces of the pandemic in the city, such as the serious impact on trade and employment, as well as the increase in poverty due to economic effects.
For many who live and work or spend a lot of time in the center of San Jose, wearing a mask makes it difficult to perceive an improvement in the air. However, some say they have seen less pollution, mainly due to the fewer cars.
Or so it seems.