A particle of dust might not seem particularly special when you wipe it off your windshield or breathe it in. But a new UC Merced professor can analyze particulate pollution for distinct chemicals that show where it originated - on a cattle feed lot, from a tomato field or almond orchard, from your car or even from the exhaust of a fast-food restaurant or the burning end of a cigarette.
Professor Wolfgang Roggejoined the faculty of the
School of Engineeringthis fall after spending 14 years at Florida International University in Miami.
Returning to California, where he earned his Ph.D. at Caltech, was particularly appropriate because two of Rogge’s recent studies address air pollution in the San Joaquin Valley.
One study examines organic chemical markers in surface soils found in fields and orchards growing almonds, cotton, grapes, tomatoes and other crops. Rogge and his colleagues from Oregon State University found that triterpenoids - 5-ring organic molecules produced by plants - varied enough among the different crops that the researchers could distinguish one field’s dust from another’s.
“The next step is to try using this technique on atmospheric samples,” Rogge explained.
Two years ago he found organic markers that can be used to trace dust from cattle feed lots - for example, a vitamin E supplement that is not completely broken down by bovine digestion.
Tracers can come from unexpected and fascinating sources - for example, the tracers now used to track vehicle emissions, hopanes, came originally from bacteria that fed millions of years ago on organic debris. Over time, small changes occurred in these bacterial hormones as the biomass matured into petroleum. These hormone derivatives aren’t found in gasoline or diesel fuel, but in lubricating oil. Very small amounts are released with exhaust to the atmosphere.
Rogge has even tracked emissions from fast-food restaurants in the Los Angeles area using cholesterol as a tracer. Today, restaurants in that area have catalytic converters to minimize their emissions.
Although Rogge strives for objectivity, his work is sometimes unavoidably controversial.
“We always get heat,” he said, “but researchers don’t take sides; that would discredit our findings. We just publish our results and hope that policymakers act on them eventually.”
Rogge looks forward to collaborating with other UC Merced
researchersto do just that in the coming years.
