Climate change driven by tiny particles in the atmosphere
Danger in the air: Atmospheric particles a fraction of the width of human hair could be driving climate change
Tiny particles could be responsible for the amount of cloud-seeding in our skies
Particles switch between absorbing and reflecting light – affecting the heating cycles of the planet
By Eddie Wrenn
PUBLISHED: 16:31, 31 July 2012 | UPDATED: 16:31, 31 July 2012
A tiny particle one thirtieth the width of a human hair could be driving pollution and climate change, researchers say.
Harvard University scientists studied atmospheric particles, a highly lethal air pollutant which appears everywhere in the atmosphere, but is more common above cities.
The tiny particles play a key role in air pollution and climate change by providing a surface for chemical reactions and reflecting and absorbing radiation.
They also act as seed surfaces for water condensation and cloud formation.
Researchers discovered that these particles separate into distinct chemical compositions during their life-spans.
Depending on the composition, the rate of chemical reactions and the amount of light that the particles reflect and absorb will change over time.
This could impact how air becomes polluted and the processes behind climate change – the warming of the earth.
The team of American scientists who worked on the project, which is published next week in the Proceedings of the National Academy of Sciences, hope it will open up new avenues to tackle air pollution, which is linked to heart and lung disease.
Allan Bertram, director of atmospheric aerosols at the University of British Columbia, who worked on the report, said: ‘We’ve confirmed experimentally that changes in relative humidity can separate the organic and inorganic material in individual atmospheric particles into distinct liquid phases, much like oil separates from water.
‘Having two liquid phases rather than one can change the rates of chemical reactions on particles, may change the amount of light the particles reflect and absorb, and impact their ability to act as seeds for clouds.
‘We need to understand as much as possible about the chemical composition, physical properties and interactions of atmospheric particles if we’re going to assess how they impact human health, regional weather patterns, and even global climate change.’
The study will pique the interest of fellow researchers, health officials and environmental groups who hope that new studies into the tiny particles will bring a greater understanding of what causes air pollution, and how it can be tackled.
Scot Martin, professor of environmental chemistry at Harvard, said: ‘I think of it as the beautiful phenomenon when I mixed food coloring, water and vegetable oil in a bottle when I was in grade school.
‘More to the point, this phenomenon is really new thinking in the atmospheric sciences, and it completely changes the way we need to think through the reactive chemistry of atmospheric particles, a key component of urban air quality.’