Depletion in the upper atmosphere's ozone layer, which filters out the sun's ultraviolet (UV) rays, was discovered last year to have spread as far as the south-central Chilean city of Puerto Montt, said research scientist Luis Da Silva.
Da Silva, working with a team of Chilean and Argentine physicists, said earlier studies showed the ozone hole used to appear for only days or weeks during the southern hemisphere spring.
"By contrast, it now appears in September and lasts until November," Da Silva, professor at Federico Santa Maria University in Santiago, told local reporters.
The findings were released as the government environmental board, CONAMA, began a national television campaign to make Chileans more aware of the danger of UV radiation caused by the ozone hole.
Under the slogan "Let's protect the ozone layer!" the campaign includes TV spots and posters advising people to avoid the midday sun, wear strong sunblocks and hats, and use anti-UV sunglasses.
Caused in part by manmade refrigerants and other chemicals floating into the atmosphere, the ozone hole has extended in previous years to the area around Punta Arenas, at the southern tip of South America, he said.
"Last year its presence was detected up to Puerto Montt," he said. Puerto Montt lies at about 42 degrees south, or about the same latitude as New York or Rome in the northern hemisphere.
Lesser damage to the ozone layer was detected in Chile as far north as Antofagasta, which lies on the Tropic of Capricorn 800 miles (1,300 km) north of Santiago.
The research, carried out by the group's own sensory equipment, coincided in part with those in a study last year by the Chilean state meteorological service.
That study found unusually high UV radiation levels in central Chile during the weeks of heaviest ozone depletion in Antarctica.