Wildfires have long been a part of Earth’s natural cycle, but as average temperatures rise due to climate change, blazes are becoming increasingly frequent and more intense.
The dangers posed by wildfires are not limited to the effects of coming into direct contact with the flames – when it comes to fires, smoke is the biggest threat.
And while people may be able to escape the flames, smoke from wildfires can spread over vast areas, as those in New York discovered last month when the city was shrouded in an orange haze caused by fires over the border in Canada.
In recent days wildfires have struck the Greek islands of Rhodes and Corfu, posing a risk to residents and tourists.
Breathing in wildfire smoke can have immediate and obvious effects, such as coughing, trouble breathing normally, stinging eyes, a scratchy throat, chest pain and a shortness of breath.
However, symptoms can also include headaches, irritated sinuses, tiredness, a rapid heartbeat and asthma attacks.
‘Exposure to smoke from wildfires is a significant and growing public health concern,’ said Dr Heather Price, a senior lecturer in environmental geography at the University of Stirling.
‘Wildfire smoke has been linked with increased emergency room visits and hospital admissions for lung-related health conditions, such as asthma and chronic obstructive pulmonary disease (COPD).
‘The evidence for impacts on cardiovascular health conditions and overall mortality is more mixed. Some people are more at risk from wildfire smoke than others, including children, older adults, people who are pregnant and those with pre-existing conditions (such as asthma).’
The dangers caused by wildfire smoke are due the particulate contained within the dark clouds that rise from each blaze.
Wildfire smoke contains a mix of hazardous air pollutants including carbon monoxide, nitrogen oxides and other PM2.5 pollutants – fine particles with a diameter of less than 2.5 micrometers that can be easily inhaled and absorbed into the bloodstream.
PM2.5 from wildfire smoke has been associated with fatalities in the general population and according to the World Health Organisation, can ’cause and exacerbate diseases of the lungs, heart, brain/nervous system, skin, gut, kidney, eyes, nose and liver. It has also been shown to lead to cognitive impairment and memory loss.’
It also notes the increased impact of wildfires on firefighters and emergency response workers, who are also at a greater risk of burns.
Some wildfire smoke may also contain aromatic hydrocarbons – naturally occurring chemical compounds – and even lead.
Increasing urbanisation means wildfires are more likely to encroach on built-up areas, causing human made, potentially toxic substances to burn.
‘Wildfires are bad but the burning of synthetic materials like plastic can make it worse,’ said Yong Ho Kim, lead author of a study into smoke toxicity.