Apr 13 2021
A team of researchers has identified the occurrence of three liquid phases in aerosol particles, thus transforming the understanding of air pollutants found in the Earth’s atmosphere. The study was headed by scientists from the University of British Columbia.
The study improves our understanding of atmospheric aerosols. Image Credit: istock.
For a long time, aerosol particles have been known to exhibit up to two liquid phases. The finding of one more liquid phase might be crucial in offering more precise atmospheric models and climate forecasts. The research was recently published in Proceedings of the National Academy of Sciences.
We’ve shown that certain types of aerosol particles in the atmosphere, including ones that are likely abundant in cities, can often have three distinct liquid phases. These properties play a role in air quality and climate. What we hope is that these results improve models used in air quality and climate change policies.
Dr Allan Bertram, Professor, Department of Chemistry, University of British Columbia
The atmosphere is filled with aerosol particles, which play a vital role in air quality. These particles cause poor air quality and tend to absorb and reflect solar radiation, thus negatively influencing the climate system.
However, the behavior of these particles is not so clear yet. Before the year 2012, climate models usually considered that aerosol particles featured only a single liquid phase.
However, in 2012, scientists from the University of British Columbia and Harvard University offered the first insights into the existence of two liquid phases in particles gathered from the atmosphere.
Researchers from UBC recently proposed that three liquid phases could form in atmospheric particles if the particles were made of medium polarity material, low polarity material and salty water.
The researchers tested this by injecting a solvatochromic dye—a dye that changes its color based on the polarity of its surroundings—into particles that contained a mixture of all three of these components.
The solvatochromic dye method has been extensively used in chemistry and biology, but it has never been used to describe the phase behavior of atmospheric aerosols. Fascinatingly, the researchers observed three different colors in these particles, which confirmed the occurrence of three liquid phases.
The team could also investigate the properties of particles that contain three phases, such as how well these particles served as seeds for clouds, and how quickly gases enter and leave the particles.
The focus of the research was on particles that contain blends of lubricating oil from gas vehicles, inorganic material discharged from fossil fuel combustion, and oxidized organic material released from fossil fuel combustion and trees.
A different number of liquid phases will emerge based on the properties of the lubricating oil and the oxidized organic material, leading to different effects on air quality and climate.
Through what we’ve shown, we’ve improved our understanding of atmospheric aerosols. That should lead to better predictions of air quality and climate, and better prediction of what is going to happen in the next 50 years. If policies are made based on a model that has high uncertainties, then the policies will have high uncertainties. I hope we can improve that.
Dr Allan Bertram, Professor, Department of Chemistry, University of British Columbia
Given the pressing nature of climate goals, policies created based on precise atmospheric modeling minimize the chances of using finances and resources toward improper goals and policies.
This research was headed by researchers from the University of British Columbia along with researchers from the University of California Irvine and McGill University.