Cities are known for their sweltering summers, where the temperature can soar and make even the most mundane activities feel like torture. The heat island effect, which is caused by the concentration of buildings, pavement, and human activity in urban areas, makes cities significantly warmer than surrounding rural areas, even at night. This, combined with the increasing frequency of extreme weather events due to climate change, can make urban living uncomfortable and even hazardous.

A team of researchers from Kyoto University set out to investigate how reducing urban heat release could help mitigate and control local rainfall. They conducted numerical simulations using a mesoscale meteorological model, selecting a severe rainstorm in Osaka City on August 27, 2023, as their case study.

The results of the study showed that reducing sensible heat fluxes over urban areas can lead to the mitigation and control of local-scale rainfall on summer afternoons. The researchers found that by regulating urban heat release, they could reduce the intensity and amount of rainfall in Osaka City.

“We are excited to learn that regulating urban heat release has the potential to help us deal with urban weather-related issues,” said corresponding author Tetsuya Takemi.

The study’s findings have significant implications for cities around the world. As climate change continues to exacerbate extreme weather events, it is essential to find ways to mitigate their impact. Regulating urban heat release could be a key strategy in controlling local rainfall and reducing the risk of flooding and other hazards associated with severe weather.

The researchers are now using a high-resolution numerical model to investigate the impacts of heat release from individual buildings and streets in real cities. They plan to combine this modeling with the mesoscale meteorological model to quantitatively assess how to control local-scale rainfall with the reduction in urban heat release.

“We hope to further advance our study on urban extreme weather and contribute to further mitigation of these problems,” said Takemi.

The study, led by George Washington University in collaboration with scientists from Washington University in St. Louis and the University of North Carolina at Chapel Hill, has mapped air pollution levels and carbon dioxide emissions across 13,189 urban areas worldwide. This comprehensive global analysis provides a powerful snapshot of how urban environments are evolving across the globe.

The research team used data from satellite observations, ground-based measurements, and computer models to measure city-level air pollution and the average amount of carbon dioxide released into the atmosphere between 2005-2019. According to Susan Anenberg, professor of environmental and occupational health at the GW Milken Institute School of Public Health, “This study shows that progress is possible but uneven, with some cities seeing worsening pollution while others are experiencing cleaner air over time.”

Key findings from the study include:

* More than 50% of cities showed links between all pollutants, suggesting they likely come from the same sources and could be reduced together.
* Urban areas in high-income regions with aggressive environmental policies saw simultaneous declines in all pollutants.
* Cities in regions undergoing rapid population and economic growth, including South Asia and parts of Africa, experienced rising pollution and emissions levels.
* Satellite remote sensing provides an unprecedented opportunity to track pollution levels in all cities worldwide.

The study’s integrated approach offers policymakers, researchers, and climate advocates a valuable new tool for assessing the effectiveness of strategies to reduce pollution. By tracking historical pollutant trends and analyzing correlations across air pollution, nitrogen dioxide, and carbon dioxide emissions, the study offers insights into how urban areas can make progress on both climate and public health goals.

Researchers have also created an interactive map and dashboard to track air pollution in cities worldwide, providing a valuable resource for policymakers, researchers, and climate advocates.

The world is facing an unprecedented crisis due to the proliferation of nanoplastics and microplastics in our environment. These tiny particles, often overlooked, pose significant health and environmental risks. However, detecting them at the nanoscale has been a daunting challenge. That’s why a team of researchers from McGill University has developed a groundbreaking technology that makes it possible to detect these plastic particles efficiently and accurately.

The HoLDI-MS (Hollow-Laser Desorption/Ionization Mass Spectrometry) test platform is a 3D-printed device that overcomes the limitations of traditional mass spectrometry. This innovative tool allows for direct analysis of samples without requiring complex sample preparation, making it a cost-effective and high-throughput solution.

“We’re excited to provide a method that is effective, quantitative, highly accurate, and affordable,” said Professor Parisa Ariya, who led the study published in Nature’s Communications Chemistry. “It requires little energy, is recyclable, and costs only a few dollars per sample.”

The HoLDI-MS platform has significant implications for international cooperation in combating plastic pollution. As part of their study, the researchers identified polyethylene and polydimethylsiloxanes in indoor air, as well as polycyclic aromatic hydrocarbons in outdoor air.

“This technology allows us to pinpoint the major sources of nano and microplastics in the environment,” said Professor Ariya. “More importantly, it enables data comparison and validation across laboratories worldwide, a crucial step toward harmonizing global research on plastic pollution.”

The development of HoLDI-MS is a testament to the power of interdisciplinary collaboration and innovation. Funded by organizations such as the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), and National Research Council Canada (NRC), this technology has the potential to revolutionize the way we detect and address plastic pollution.

As the world continues to grapple with the consequences of plastic waste, the HoLDI-MS platform offers a beacon of hope. By providing a cost-effective and efficient solution for detecting nanoplastics and microplastics, this technology can help us take a significant step toward mitigating the impact of plastic pollution on our environment.