Chemical clean-up

Chemists at the

and

have discovered that natural chemical processes in the atmosphere may be removing smog and other damaging hydrocarbons at a faster rate than once believed.

The scientists report that naturally-occurring atmospheric chemicals react with sunlight more effectively than scientists previously thought, breaking down smog and other pollutants after they absorb energy from sunlight.

While many molecules have been known to behave in this way, producing natural air cleaners called OH radicals, the chemicals the team studied have for the first time been observed to produce smog-destroying OH radicals at low ultraviolet wavelengths.

This observation had long eluded scientists primarily because photochemistry at these wavelengths had been difficult to study. But a sensitive laser technique allowed the scientists—Amitabha Sinha and Jamie Matthews of UCSD and Joseph Francisco of Purdue—to record these reactions for the first time.

“Thanks to an innovative laser technique that at last allowed us to observe these chemicals in action, we now theorise that the atmosphere may produce up to 20 percent more OH radicals from these chemicals than we once thought,” said Francisco, professor of earth and atmospheric sciences and chemistry at Purdue. “We now have a better understanding of an atmospheric process that could be giving our pollution-weary lungs more breathing room.”