Global Smoke Pollution From Landscape Fires Affects More Than 2 Billion People, Study Finds

Smoke pollution is a form of air pollution that occurs when harmful gases, dust particles, and pollutants escape into the atmosphere from fires.

It can have serious impacts on human health, such as increasing the risk of respiratory and cardiovascular diseases, as well as on the environment, such as contributing to climate change and reducing visibility.

A recent study by Australian scientists has revealed the alarming increase in smoke pollution from landscape fires across the globe over the past two decades and its implications for the world's population and public health.

How did the scientists measure global smoke pollution?

(Photo : MAHMOUD ZAYYAT/AFP via Getty Images)

The study, published in the journal Nature, was led by Professors Yuming Guo and Shanshan Li, from Monash University's School of Population Health and Preventive Medicine.

The researchers used a machine learning approach to estimate the global daily air pollution from all fires from 2000 to 2019, based on inputs from chemical transport models, ground-based monitoring stations, and gridded weather data.

The researchers focused on two major pollutants that are emitted by fires: particulate matter (PM) and ozone.

PM is a mixture of solid and liquid particles that vary in size, composition, and origin.

PM2.5 refers to particles that are less than 2.5 micrometers in diameter, which can penetrate deep into the lungs and bloodstream.

Meanwhile, ozone is a gas that is formed by the reaction of sunlight with nitrogen oxides and volatile organic compounds. It can irritate the eyes, nose, and throat, and damage the respiratory system.

The researchers calculated the exposure levels of PM2.5 and ozone for each person in the world, based on their location and the concentration of pollutants in the air.

They also assessed the health impacts of smoke pollution by estimating the number of deaths and disability-adjusted life years (DALYs) attributable to PM2.5 and ozone exposure.

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What were the main findings and implications of the study?

The study found that smoke pollution from landscape fires has increased significantly over the past two decades, both in terms of frequency and intensity.

The study also found that smoke pollution has affected more than 2 billion people annually, with each person having on average 9.9 days of exposure per year.

Furthermore, exposure levels were higher in low-income countries than in high-income countries and that some regions, such as Central Africa, Southeast Asia, South America, and Siberia, were particularly vulnerable to smoke pollution.

According to the study, smoke pollution has caused substantial health burdens across the globe, especially due to PM2.5 exposure.

It is etimated that smoke pollution was responsible for about 339,000 deaths and 9.7 million DALYs per year during 2000 to 2019, accounting for about 7% of the total deaths and DALYs attributable to ambient air pollution.

The study also found that smoke pollution had a greater impact on children under five years old and adults over 65 years old, who are more susceptible to respiratory infections and chronic diseases.

The link between smoke pollution and climate change has also been highlighted by the researchers, as both are driven by fossil fuel combustion and landscape fires.

As a suggestion, the researchers said that reducing albedo, or the reflecivity of the Earth's surface may help since smoke pollution can exacerbate climate change by increasing greenhouse gas emissions, such as carbon dioxide and methane.

Conversely, climate change can worsen smoke pollution by increasing the frequency and severity of droughts, heat waves, and wildfires.

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