The assessment of officials' performance should be based on their contribution towards improving the public's health and the environment and not just their ability to boost economic output, leading respiratory disease specialist Dr Zhong Nanshan said yesterday . Speaking on the sideline of the annual session of the National People's Congress, Zhong said smog was the major cause of respiratory diseases and led to lung cancer and illnesses affecting the cardiovascular and nervous systems. If ignored, he said, it could lead to disastrous results. Quoting an American study spanning 26 years, Zhong said that when levels of PM2.5 - tiny particles that can penetrate deep into the lungs - increased by 10 micrograms per cubic metre, the death rate from lung cancer rose by 15 to 27 per cent. He also quoted a Hong Kong study of 50,000 patients which found the fatality rate among respiratory patients increased to 11 per cent if levels of PM 2.5 rose from around 20 mcg to 200 mcg per cubic metre. State media earlier quoted Zhong as saying lung cancer cases in Beijing had surged by 60 per cent in the past decade. We have now reached this stage, where food, water and air - elements of people's basic health and survival - are at risk Zhong, well known for his role in fighting the outbreak of severe acute respiratory syndrome 10 years ago, said officials should not be assessed on their performance in raising gross domestic product alone. They should also be assessed on their contribution towards improving the environment, he said. "We have now reached this stage, where food, water and air - elements of people's basic health and survival - are at risk," he said. "At this stage, do we put GDP first or health first? He said officials who made efforts to improve the environment "genuinely care for the people". Zhong said that if officials were bent on cleaning up the environment, it should not take many years to make progress, citing the example of Guangzhou, which saw its air quality improve markedly in the run up to the Asian Games in 2010. "But if we don't take action, give it another 10 years, I don't know what Beijing is going to be like," he said. "If we allow it to get worse, the social instability it creates would be unimaginable. I'm not being alarmist."