In a world first study of daily ambient fine particulate matter ( PM 2.5 ) across the globe, a Monash University study has found that only 0.18% of the global land area and 0.001% of the global population are exposed to levels of PM 2.5 - the world’s leading environmental health risk factor – below levels of safety recommended by Word Health Organization (WHO). Importantly while daily levels have reduced in Europe and North America in the two decades to 2019, levels have increased Southern Asia, Australia, New Zealand, Latin America and the Caribbean, with more than 70% of days globally seeing levels above what is safe.
A lack of pollution monitoring stations globally for air pollution, has meant a lack of data on local, national, regional and global PM 2.5 exposure. Now this study, led by Professor Yuming Guo, from the Monash University School of Public Health and Preventive Medicine in Melbourne, Australia, and published in the prestigious journal, Lancet Planetary Health, has provided a map of how PM 2.5 has changed across the globe in the past decades
The research team utilised traditional air quality monitoring observations, satellite-based meteorological and air pollution detectors, statistical and machine learning methods to more accurately assess PM 2.5 concentrations globally, according to Professor Guo. “In this study, we used an innovative machine learning approach to integrate multiple meteorological and geological information to estimate the global surface-level daily PM 2.5 concentrations at a high spatial resolution of approximately 10km ×10km for global grid cells in 2000-2019, focusing on areas above 15 μg/m³ which is considered the safe limit by WHO (The threshold is still arguable),” he said.
The study reveals that annual PM 2.5 concentration and high PM 2.5 exposed days in Europe and northern America decreased over the two decades of the study - whereas exposures increased in southern Asia, Australia and New Zealand, and Latin America and the Caribbean.
In addition, the study found that:
According to Professor Guo, the unsafe PM 2.5 concentrations also show different seasonal patterns “included Northeast China and North India during their winter months (December, January, and February), whereas eastern areas in northern America had high PM 2.5 in its summer months (June, July, and August),” he said.
“We also recorded relatively high PM 2.5 air pollution in August and September in South America and from June to September in sub-Saharan Africa.”
He added that the study is important because “It provides a deep understanding of the current state of outdoor air pollution and its impacts on human health. With this information, policymakers, public health officials, and researchers can better assess the short-term and long-term health effects of air pollution and develop air pollution mitigation strategies.”
The Lancet Planetary Health
Data/statistical analysis
Not applicable
Global estimates of daily ambient fine particulate matter concentrations and unequal spatiotemporal distribution of population exposure: a machine learning modelling study
6-Mar-2023