Studying clouds to find global answers
Some of the same chemicals that a number of scientists believe are influencing climate change may be having an equally important effect on people’s health, as they inhale those chemicals into their bodies.
UC Riverside professor Akua Asa Awuku is studying both.
Using the world’s largest atmospheric chamber at UCR’s College of Engineering/Center for Environmental Research and Technology, Asa Awuku is trying to determine how airborne particles from emissions influence the formation of clouds. Clouds affect regional and global temperatures, she said, and the same process that leads to cloud formation in the sky causes them to form in people’s lungs.
“It’s absolutely parallel,” Asa Awuku said.
Understanding how particles help generate clouds and how and when the particles fall in precipitation provides important information on clouds’ behavior and what influence they might have on regional and global temperatures. The same data might shed light on how our lungs are affected by the air we breathe, she said.
For years, the engineering school has been at the forefront of detecting and studying manmade emissions in Southern California’s air and the chemical reactions they contribute to. Those greenhou timberland outlet se gases are largely thought to be responsible for the global warming trend over the past century. Studies by the United Nations Intergovernmental Panel on Climate Change have blamed human activity as the primary cause for increased global temperatures and rising sea levels.
The airborne particles associated with those gases often contribute to cloud formation. If the clouds are large enough, they help cool the Earth by reflecting solar radiation.
It’s those clouds and their cooling effect on the warming planet that interest Asa Awuku and her team of 16 researchers.
“We don’t really understand the cooling trends,” she said.
Scientists know that cloud formation has increased in recent years and that the clouds are lasting longer. Instead of days, their lifetimes sometimes last weeks now. The engineering school’s three story tall atmospheric chamber, completed in 2003, is the best tool for studying how and why clouds are created and how they behave. The space age looking interior of the chamber has two floor to ceiling plastic bags. Emissions are pumped into four floor vents under each bag.
One wall facing the bags is lined with ultraviolet light tubes, and a 200 kilowatt arc light is anchored in the wall’s center. The arc light, 2,000 times brighter than a household 100 watt bulb, mimics the conditions of sunlight. Many of the chemicals being studied react to sunlight in the atmosphere. The other walls of the chamber are covered in highly reflective aluminum called Everbright.
“We look at particles in the atmosphere,” Asa Awuku said. “They act as seeds for cloud droplets to form. I don’t think a lot of people understand you can’t make a cloud without a particle.”
Water vapor alone doesn’t create clouds. Asa Awuku uses the example of the way water droplets appear on a mirror in a steamy bathroom to illustrate this concept.
“You need a surface for the water to condense on,” she said.
The smaller the droplets, the more reflective the clouds, she said.
The reason all this matters, she said, is that if scientists can determine what clouds will be formed, how long they might last, how reflective they’ll be and what particles will fall to Earth when the clouds release rain, then we should know more about what to expect from the environment, not only today but long term.
“We’re improving our predictive capabilities,” she said, “how we predict climate and air quality. These things influence food supply, energy supply, water resources, personal health.”
Many of the gases responsible for warming the planet will remain in the atmosphere for decades, and scientists have been trying to determine how to remove or counteract them.
A compound that particularly interests Asa Awuku is black carbon, found in emissions from vehicles and other combustion. It tends to be washed out of clouds by rain and could be a potential mechanism for reducing the effects of atmospheric warming.
“Greenhouse gases warm and black carbon warms,” Asa Awuku said. “But a greenhouse gas typicall timberland outlet y has an atmospheric lifetime of 100 years. (With) black carbon, as soon as it rains, it’s removed. So, removing b timberland outlet lack carbon is a great way to reduce atmospheric influence. This is a quick way to reduce warming.”
But how we might go about increasing the rate of removal for black carbon, she said, has yet to be determined.
“We still don’t know how (black carbon) influences clouds,” she said.
She is studying those interactions using a two foot high cylindrical cloud chamber. Gases are fed into the cloud chamber from tubes connected to the atmospheric chamber, and humidity is added to form clouds.
Knowing how the particles behave in a cloud can be extrapolated into how they beh timberland outlet ave when a person breathes them in. Moisture in the body and inhaled particles create clouds in the lungs. A particle that falls out of a cloud sooner, through precipitation, may be less dangerous than one that remains in the air and is carried deeper into the tiny sacs of the lungs where oxygen is absorbed by the blood.