Gerhard Ertl of Germany won the Nobel Prize in chemistry for research that may help scientists discover ways to protect the environment.

Mr. Ertl’s work in surface chemistry helped explain how catalysts clean car emissions and how gases damage the Earth’s protective ozone layer, the Stockholm-based Nobel Foundation said yesterday in a statement on its Web site. His studies also shed new light on a method for making fertilizer that had earned fellow German Fritz Haber the Nobel Prize in 1918.

“This is a great choice and highly deserved,” a physics professor at the University of Wisconsin, Franz Himpsel, said. Mr. Himpsel sits on the scientific advisory board of the Max Planck Institute in Berlin.

Mr. Ertl, who turned 71 yesterday, will receive $1.6 million in a December 10 ceremony in Stockholm. Born in Bad Cannstadt, Germany, the piano-playing researcher earned his doctorate in physical chemistry in 1965 from the Technical University in Munich. He is professor emeritus at the Fritz-Haber-Institut of the Max-Planck-Gesellschaft in Berlin.

“I can’t really come to my senses,” Mr. Ertl said as scientists, doctoral students, and staff sang “Happy Birthday” on the lawn of the institute and sipped champagne. “This is an achievement for us all and for the institute.”

The German scientist used extremely powerful microscopes and high vacuum conditions to show how molecules break up and form new particles on surfaces. He first studied the behavior of hydrogen on metal.

His experiments grounded on sound research a field previously considered to be “black magic, complete trial and error,” Mr. Himpsel said.

Mr. Ertl then turned to the Haber-Bosch process, which captures nitrogen from the air to make fertilizer. The method now produces about 100 million tons of fertilizer a year. One percent of the world’s annual energy supply is consumed in the Haber-Bosch process. Last year, Germany’s BASF AG paid $5 billion to acquire Engelhard Corp. to expand its offering of catalysts.

The prize winner’s work may also help scientists understand why the ozone layer is deteriorating, the Nobel Foundation said. Freons used in air-conditioning reduce the ozone layer by reacting on the surfaces of small ice crystals high in the atmosphere. Mr. Ertl is the second German awarded a prize this year, after Peter Grünberg shared the physics prize with Albert Fert of France for developing the technology in miniaturized hard disks for computers and music players such as Apple Inc.’s iPod.

“This is much more fundamental; it’s not something you can carry around in your pocket like an iPod,” a professor of chemistry at the University of Lausanne, Tom Rizzo, said in an interview. On Monday, Mario Capecchi and Oliver Smithies of America and Martin Evans of Britain, who discovered how to alter genes in mice so the animals could be used for medical research, won the medicine award.

Last year, American researcher Roger Kornberg won the chemistry prize for showing how genes are copied at the molecular level, enabling the human body to make use of information stored in DNA.

Annual prizes for achievements in physics, chemistry, medicine, peace, and literature were established in the will of Alfred Nobel, the Swedish inventor of dynamite, who died in 1896.

The Nobel Foundation was established in 1900 and the prizes were first handed out the following year. The economics prize was created in 1969 in memory of Nobel by the Swedish central bank. Only the peace prize is awarded outside Sweden, by the five-member Norwegian Nobel Committee in Oslo.