Two studies in Brazil and the USA have found that wildfires affect the air quality in distant cities.
A study by the UK’s University of Birmingham, working with Brazil’s Federal University of Technology – Londrina, and Sweden’s University of Stockholm claims that wildfires in southeast Brazil produce airborne pollution as far away as Sao Paulo.
Most Brazilian wildfires occur in the dry season between July and September in the Amazon and Cerrado regions, and the Pampas.
Burning biomass produces low-lying ozone due to the South Atlantic subtropical high-pressure system. Transported from the fire, the pollution contributes to poor air quality and smog in cities such as Sao Paulo.
Professor Roy Harrison of the University of Birmingham said the state of Sao Paulo has taken measures to curb air pollution such as controlling sulphur dioxide from industrial sources and enforcing cleaner vehicle and fuel standards.
“However, present results indicate that policies targeting the reduction of biomass burning are of utmost importance to improve urban air quality, particularly in densely populated areas where high pollutant concentrations are frequently observed,” he explained.
Dr Admir Creso Targino from the Federal University of Technology added, “We need enhanced governance at regional, national and international levels to combat biomass burning practices in Brazil and its neighboring countries.”
A similar study has been published in the European Geosciences Union journal Atmospheric Chemistry and Physics.
Researchers in the lab of Drew Gentner, associate professor of chemical and environmental engineering at Yale School of Engineering and Applied Science, monitored the air quality at the Yale Coastal Field Station in Guilford, Connecticut, and four other sites in the New York metropolitan area.
In August 2018, they observed two spikes in the presence of air pollutants both coinciding with New York-area air quality advisories for ozone.
The pollutants were the kind found in the smoke of wildfires and controlled agricultural burning, which the researchers traced back to fires on the western coast of Canada for the first event, and the southern USA in the second event.
Biomass burning is a major source of air pollutants, producing particulate matter with a diameter of less than 2.5 micrometers.
PM2.5 has been shown to have serious health effects when inhaled.
Gentner said, “Given the sensitivity of people to the health effects emerging from exposure to PM2.5, this is certainly something that needs to be considered as policymakers put together long-term air quality management plans.”
Lead author Haley Rogers, who was an undergraduate student when the study was conducted, added, “When people are making predictions about climate change, they’re predicting increases in wildfires, so this sort of pollution is likely going to become more common.”