The Covid-19 pandemic has forced many countries to impose lockdowns and social distancing measures to contain the spread of the virus.
However, in São Paulo, Brazil, the largest city in Latin America, the air quality did not improve as expected.
A recent study found that atmospheric pollutants in São Paulo exceeded recommended levels even at the height of the pandemic.
The sources and effects of air pollution in São Paulo
Miguel Schincariol/Getty Images
São Paulo is a megacity with more than 20 million inhabitants and a large vehicle fleet that emits significant amounts of air pollutants, such as particulate matter (PM), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3).
These pollutants can cause respiratory and cardiovascular diseases, as well as increase the risk of mortality.
According to the study, the main sources of air pollution in São Paulo during the pandemic were biomass burning in the Amazon region, which transported large amounts of PM to the city, and the local traffic, which remained high despite the social isolation measures.
The study also found that the meteorological conditions, such as temperature, humidity, and wind speed, influenced the dispersion and concentration of the pollutants.
It used data from 60 air quality monitoring stations in São Paulo and satellite images to analyze the levels of PM2.5, PM10, NO2, SO2, CO, and O3 from March to September 2020, when the pandemic was most severe in the city.
The results showed that the average concentrations of PM2.5 and PM10 were 30 and 58 micrograms per cubic meter, respectively, which are double the levels considered safe by the World Health Organization (WHO).
The levels of NO2, SO2, CO, and O3 also exceeded the WHO guidelines and the Brazilian standards.
The study estimated that exposure to PM2.5 alone caused about 14,000 deaths and 6.8 billion US dollars in economic losses in São Paulo in 2020.
The authors also warned that the high levels of air pollution could worsen the effects of COVID-19, as both can damage the lungs and the immune system.
The implications and recommendations for air quality management
The study highlighted the need for more effective air quality management policies in São Paulo, especially during the pandemic, when the population is more vulnerable to the health impacts of air pollution.
The authors suggested that the government should implement stricter emission standards for vehicles, promote the use of cleaner fuels, such as ethanol, and increase public transportation options.
They also recommended that the public should avoid outdoor activities when the air quality is poor and wear masks to protect themselves from the pollutants.
The study also pointed out the importance of regional and international cooperation to reduce the emissions from biomass burning, which affect not only São Paulo but also other cities and countries in South America.
The authors urged the authorities to enforce the laws that prohibit illegal deforestation and fires in the Amazon and to support the conservation and restoration of the forest.
The pandemic has exposed the fragility of the urban environment and the need for more sustainable and resilient solutions to improve the air quality and the well-being of the population.
