New research explores the health risks of PM2.5 and global efforts to reduce it. The article highlights a study showing that global exposure to PM2.5 has declined since 2011, largely due to China’s efforts. The article highlights the health benefits of reducing exposure and the need for continued surveillance and mitigation, especially in densely populated areas.
Researchers from the University of Washington quantified changes in air pollution from 1998 to 2019 and noted that further emissions reduction measures are still necessary.
Ambient fine particulate matter (PM2.5) is a significant risk to global environmental health. These particles are 2.5 microns or smaller in size, which is tiny enough to be inhaled, causing a variety of health problems. They can trigger respiratory diseases such as asthma and bronchitis, as well as cardiovascular problems, including heart attacks and high blood pressure. For children, exposure to PM2.5 can cause lasting developmental disabilities. In addition, for ordinary people, exposure to PM2.5 increases the risk of premature death.
PM2.5 is mainly produced through the burning of traditional energy sources such as fossil fuels or wood. To mitigate these widespread negative effects of exposure to PM2.5, some countries have taken steps to reduce exposure to PM2.5. But how effective are these efforts to reduce PM2.5, and which region or regions are most responsible for driving global PM2.5 reductions?
Research results on PM2.5
Researchers working with Randall Martin, the Raymond R. Tucker Distinguished Professor in the McKelvey School of Engineering at Washington University in St. Louis, looked at PM2.5 data from 1998 to 2019 to find out.
"The importance of PM2.5 as a major risk factor for human health prompts us to assess its long-term changes," Martin said. "We sought to analyze satellite-derived PM2.5 estimates to gain insights into changes in global and regional PM2.5 exposure and their impact on health."
The research team's analysis, published in Nature Communications on September 2, showed that global population-weighted PM2.5 exposure is related to pollution levels and population size, starting to increase in 1998, peaking in 2011, and then declining steadily from 2011 to 2019, mainly due to reduced exposure in China and slower growth in other regions.
Li Zhi (transliteration), first author of the study and a scientist in Martin's research group, said: "Prior to this work, there was a gap in knowledge about the quantitative local/regional contribution to global population exposure to PM2.5 and its changes. We developed a new regional decomposition method that considers pollution levels and population size together, and thus delineated the regional contribution time series of global PM2.5 air pollution for the first time."
The study found that PM2.5 exposure has declined in many regions since 2011, including continued declines in North America and Western Europe. He believes that the recent decline in China is particularly noticeable.
"China's strict air quality management has been most evident since 2013, becoming the largest contributor to the global air quality reversal," Li said. "Based on our regional attribution, more than 90% of the reduction in global average exposure from 2011 to 2019 came from China. This result was surprising when it was obtained, but it can be well explained by China's emission reduction efforts that have led to rapid declines in PM2.5 concentrations, benefiting nearly a fifth of the world's population."
Benefits from reducing PM2.5 exposure include 1.1 million fewer premature deaths in China alone between 2011 and 2019, and widespread improvements in health outcomes. Future interventions to reduce PM2.5 exposure will have a greater impact on an aging and growing global population.
"By combining PM2.5 data with health data and exposure-response models, we also found that despite the recent continued reduction in global PM2.5 pollution, population aging and growth are currently the main challenges in mitigating the health effects of PM2.5," Li said. "Reducing PM2.5 by the same amount now will have stronger health benefits than it did 20 years ago, and our study highlights this global phenomenon."
The research team calculated that millions of premature deaths globally in 2019 could still be attributed to PM2.5, highlighting the urgent need to continue reducing PM2.5 exposure. Careful monitoring, especially in currently under-monitored but large-population regions, including South Asia and the Middle East, is critical to continue improving air quality and assessing the effectiveness of emissions reduction measures.
Compiled from: ScitechDaily