Aug 28, 2013 - Claremont, Calif. -
Madeline Hartley '16 holds sample of captured particles.
Air is pulled down through the lab's rooftop inlet.
Created by sources such as forest fires and vehicle emissions, brown carbon absorbs light, which heats up our planet and contributes to climate change. However, particles composed of brown carbon may also seed clouds, so their net impact is still uncertain. By studying the brown carbon particles, researchers might help gauge the efficacy of efforts to reduce air pollution.
“Organic [brown] carbon doesn’t last long in the atmosphere. It may be there for just two weeks, whereas CO2 lasts for decades,” said Hartley. “So, if you take an area and stop its organic carbon output, this research could be used to show an immediate decrease in carbon concentration that is very observable.”
The students are also studying the effect of fog generation and evaporation on brown carbon production. Since fog isn’t always available in Claremont, Littleton built a fog chamber to create his own. Outside air is fed into the 1-foot-by-2-foot chamber, which creates fog vapor using a thermal gradient. The vapor forms into water droplets around the air particles, and then the droplets pass through tubes containing a desiccant, which evaporates the moisture from the particles.
These “fog-processed” particles are then fed into the particle sampling system to analyze their light absorption qualities and the presence of brown carbon.
“Fog generally forms on the ground and settles into areas where you have more pollution. One possibility is that the cycles of fog droplet and evaporation may change the [brown carbon] particles’ chemistry,” said Littleton.
The project is part of Harvey Mudd College's Summer Research Program, which engages students in 10 weeks of full-time research. More than 175 students pursued research projects this summer alongside 45 faculty members in biology, chemistry, computer science, engineering, mathematics and physics.
Media Contact: Judy Augsburger