The elevated dangers of smoke from wildland-urban interface fires – wildfires that encroach into urban spaces – has been revealed by new research which also finds that the threat is increasing.
As cities and towns expand, so does the wildland-urban interface (WUI), to the extent that it now occupies around 5% of the world’s land area, excluding Antarctica.
This brings a greater threat of WUI fires and the report cites devastating examples from the last ten years in Greece, Hawaii and, most recently, Southern California.
The team from the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR) used a database of WUI fires and advanced computer modeling techniques which included carbon monoxide chemical tracers, allowing them to estimate the sources of emissions and thus identify which were wildland and which were WUI fires.
They found that while WUI emissions represented just 3.1% of those from all the world’s fire in 2020, it was responsible for 8.8% of the premature deaths these fires caused by these emissions
NSF NCAR scientist Wenfu Tang, the lead author. said: ‘Even though the emissions of WUI fires are relatively small globally, the health impacts are proportionately large because they’re closer to human populations. Pollutants emitted by WUI fires such as particulate matter and the precursors to ozone are more harmful because they’re not dispersing across hundreds or thousands of miles.’
In this research the team only looked at the heath impacts of WUI fires caused by ozone and PM2.5. Because WUI fires involve the burning of a huge range of materials, the toxicity of the chemicals released is greater and leader to greater health impacts that studied here.
As such, following this research, Tang plans to look at difference in emissions from wildland fires that consume trees and other vegetation as opposed to WUI fires that burn down structures that often contain additional toxic substances. He says: ‘It is very important to have an emission inventory that explicitly accounts for the burning of structures. We need to know what is being burned in order to determine what is going up in smoke.’
The full research can be read here.
Photo: Kurt Hudspeth