Chinese and foreign scientists on Monday called for more attention to tackle urgent environmental issues other than climate change, as homemade and imported pollutants threaten people's health.

"Recent studies show that some chemical pollutants' air concentrations remain surprisingly high in parts of Africa and Asia, where these chemicals were never extensively used," Kevin C Jones, a professor at Lancaster University in the United Kingdom, told an environmental forum.

Jones said based on his study program, conducted in cooperation with the Chinese Academy of Sciences (CAS), the air concentration of polychlorinated biphenyl (PCB), a chemical pollutant, remains 1,000 or even 10,000 times higher in China, India and Africa, than in Europe and North America.

He added that more study was required to determine whether there was a relationship between the concentration of PCB in the air and diseases such as cancer.

"But at least it has a bad impact on people's health, for those living in the polluted areas, as the blood tests of the local volunteers show," he said.

Delegations from around 200 countries on Monday gathered in Durban, South Africa, to start a new round of global climate change talks, in an effort to slash greenhouse gas emissions.

Jones explained that PCBs, which mainly come from old-style light fittings, photocopying paper and paint, were widely used in developed countries like the United Kingdom and the United States.

Although they were banned in the 1970s, they can still be found today in developing regions, he said.

A major reason is the "waste trade" between rich and poor countries, with people in poorer regions taking raw materials like metal or plastic from the products to make money, Jones said.

But usually the waste is not handled properly, so it remains in the soil, air and water for years.

Lu Yonglong, president of the Scientific Committee on Problems of the Environment, a Chinese non-governmental organization, and a professor at the CAS, pointed out another reason is that "polluting industries are transferring from developed areas to developing regions".

Today, technologically backward plants and mines that produce shoddy products, waste resources and cause serious pollution mainly exist in developing countries, and those areas lack the funding and technology to tackle the resulting environmental problems, he said.

Developed countries should take more responsibility for environmental protection by offering technical and financial support to poorer countries, Lu added.

"It is similar to combating climate change. The developed countries accumulated more greenhouse gas through earlier industrialization, as well as more experience in reducing pollution, and they should share it with the developing nations, as this is a global issue," he said.