- Wilderness burning, widely used to support recreational shooting in the UK, releases tiny pollution particles known as ‘particle pollution’, which pose serious health risks when inhaled.
- New research shows that on average, prescribed incineration exposes more than half a million more people to unsafe levels of particulate pollution, with peak exposures affecting up to 2.3 million people.
- Particulate matter exposure was highest in northern England, northern Scotland, and eastern parts of the country.
- Particle pollution (PM2.5) emissions from wildland burning were equivalent to one-third of emissions from road transport.
When wildlands burn, toxic air pollutants are released and can travel far from the source to nearby towns and cities. Breathing in these tiny pollution particles increases the risk of heart and health problems for people who are repeatedly exposed to dangerous levels.
New research from the University of Leeds and the RSPB shows that the deliberate burning of moorland for recreational shooting exposes an additional 550,000 people on average to unsafe levels of particulate pollution, with areas in the north of England and northern and eastern Scotland being the most affected. Over the months analyzed, these intentional burns exposed nearly one in five people in the affected areas to dangerous levels of pollution.
Vast swaths of moorland in northern England and Scotland are burned every year, some by bushfires but mostly as a result of deliberate ‘prescribed’ burning. Prescribed burning is primarily done to maintain a mosaic of heather-dominated moorland for ruffed grouse, a popular game bird that feeds on young shoots and nests in old vegetation.
Building on previous research by the RSPB that estimated the area of prescribed burning carried out each year in the UK, new research by the University of Leeds and the RSPB converted the area of deliberately burned wasteland into the impact on air quality in surrounding communities. The paper is published today in the journal Environment Research Letters.
In addition to negative environmental impacts such as carbon storage and water quality, wildland burning also produces a variety of toxic air pollutants, including particulate matter (PM). Exposure to particulate matter less than 2.5 micrometers in diameter (PM2.5), even for short periods of time, can increase risks to heart and lung health. Scientists have estimated daily PM2.5 emissions from wildland burning from 2017 to 2022, which primarily covers prescribed burning but also wildfires. They then modeled how emissions from these burns would be spread by weather and atmospheric conditions.
The results revealed that particulate matter emissions from moorland burning account for almost a third of the particulate matter produced by road transport across the UK (30%). From 2017/18 to 2021/22, heath burning generated 1,300 tonnes of particulate matter per year, equivalent to around 1.5% of the UK’s total anthropogenic primary PM2.5 emissions. The regions with the highest PM2.5 emissions were Yorkshire and the Humber, north-east England, east Scotland and north Scotland.
The scientists then focused on a period when wildfires accounted for less than 5% of the area burned (October 2017 to April 2018) to identify impacts specifically attributable to prescribed burning. They used a combination of satellite data and regional air quality models to estimate the impact of prescribed burning on air pollution and calculate where in the UK people are exposed to pollution. On the days of prescribed burns, an average of 550,000 more people were exposed to PM2.5 levels above the World Health Organization (WHO) recommended limits. Over the entire period, an estimated 2.3 million people were exposed to PM2.5 concentrations above thresholds through prescribed wilderness burning. This corresponds to almost one in five people (19%) in the affected area.
To create ideal conditions for ruffed grouse, game breeders can use prescribed burning as a means to form a mosaic of heather of varying age and structure. Collectively, they become so large that they can be seen from space. This burning occurs frequently in internationally important peatland habitats, leading to the release of stored carbon into the atmosphere, water pollution, increased flood risk, and loss and degradation of wildlife habitat.
Those who conduct prescribed burning for ruffed grouse management also often claim that it reduces wildfire risk, but this is not fully supported by evidence. While many international landscapes use prescribed burning to manage vegetation, UK landscapes are not naturally adapted to fire. This means alternative approaches such as rewetting peatlands can reduce the risk of wildfires without releasing harmful PM2.5 particles through combustion. It is clear that prescribed incineration is a significant source of particulate matter pollution in areas of the north of England and Scotland. Reducing this pollution will require updating upland management approaches and restoring peatlands to their natural fire-resistant state. This is especially important as warmer springs and longer dry spells due to climate change increase the risk of prescribed fires turning into wildfires.
Lead author Dr Irish Graham from the University of Leeds said: “Traditionally, prescribed burning has been seen as a regional air quality problem. Our results show that prescribed burning increases PM2.5 concentrations over a much wider area, impacting towns and cities in northern England and Scotland. “On days when burning occurs, millions of people will be exposed to increased pollution from PM2.5 concentrations that exceed World Health Organization air quality guidelines. Discussions around wilderness management, bushfire risk and peatland restoration continue in the UK.” Moorland managers should consider the air quality impacts of prescribed burning and explore alternative approaches where possible. ”
Tom Aspinall, RSPB’s Senior Uplands Policy Officer, said: “The environmental impact of burning on our precious upland peatland habitats is well-documented and can lead to the degradation of peatland landscapes, which are essential for both wildlife and carbon storage. This new research reinforces the need to limit peatland burning and take steps to restore uplands.”
“This is one of the reasons why we are calling on the UK Government to introduce a licensing system to regulate grouse moor management practices across the UK, in line with recent Scottish law changes. Many parts of Europe already have licensing in place and are well regulated. Evidence shows that filming is successful in a controlled and environmentally sustainable manner, and we believe this is a wise and appropriate way to bring about the changes needed to help upland landscapes thrive and fulfill their potential.” ”
Photo by Greg Willson on Unsplash
