How Far Does Wildfire Pollution Spread?

The pollution caused by the smoke from wildfires can travel hundreds of miles, according to a new study from Yale University in the USA. The researchers, whose findings were published in the journal Atmospheric Chemistry and Physics, were focusing specifically on levels of black carbon and particulate matter 2.5 (PM2.5) in New York City over recent years.

Isolating spikes in the air pollution found in the biggest city in the States, the authors of the study were able to connect those periods of poor air quality directly to wildfires in other parts of the continent. On one occasion, they attributed a spike to wildfires in British Columbia on the western coast of Canada, while on another, they found a link to blazes in the southeast of the USA.

Itinerant emissions

The investigation was conducted by the research team of Professor Drew Gentner, who examined the data collected by five monitoring sites around New York City. Fortunately, our ability to monitor and quantify concentrations of PM and black carbon has improved massively in recent years, allowing the scientists to compare that information to satellite imaging readouts.

They then cross-referenced both sets of data against computer simulation models, which were developed by the National Oceanic and Atmospheric Administration (NOAA) and are capable of backtracking air movement over time. They found that the BC wildfires in 2016 and 2017 – which remain Canada’s worst ever wildfires – caused an initial spike in PM2.5 pollution, while a second one was precipitated by controlled burns in south-eastern US the following year.

Serious consequences

The findings are concerning, not least because of the severity of PM2.5 pollution. So named for its microscopic size (less than 2.5 micrometres in diameter, which is roughly 30 times thinner than a single human hair), PM2.5 can be easily inhaled and even absorbed into the bloodstream. Once there, it can wreak all sorts of havoc on the body and its internal organs.

Among other diseases, prolonged exposure to PM2.5 has been linked with lung and brain cancer, heart disease and other cardiovascular complications, as well as a whole host of mental problems. Studies have found correlations between inhalation of PM2.5 and dementia, anxiety, schizophrenia and plenty of other troubling conditions not easily discernible by the naked eye.

A glimpse into the future?

The fact that PM2.5 is able to endure in the atmosphere for longer than most other components of wildfire smoke is the reason why it’s able to travel such large distances. Air quality in cities is an increasingly prominent concern among both environmentalists and the mainstream media, but it’s not often linked with such far-off sources. However, those behind the study predict that this kind of phenomenon is only set to become more commonplace in the future.

“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,” explained Haley Rogers, lead author on the Yale paper. “So when people are planning for air pollution and health impacts, you can’t just address local sources.”