But public criticism against the deteriorating environment does not stop so easily. Some officials and scholars say two major conventional pollution indicators (COD or chemical oxygen demand and SO2 or sulfur dioxide) cannot reflect the precise quality of the environment. Other indictors such as ammonia nitrogen in water and oxynitrides in the atmosphere should be included in emission reduction indictors to improve the quality of the environment.

Though these indicators, in all probability, have been incorporated into the 12th Five-Year Plan for the environment, Su has reservations about the real social effects of such good intentions. Common people's criterion for good environment is different from that of experts, for it does not necessarily depend on statistics. "What the public cares most about is health risks," Su says. Many people think the environment is deteriorating because of continued environmental pollution.

This is a difficult problem to solve. On one hand, rapid development of low-end heavy and chemical industries, high population density and lack of necessary protection mechanism contribute to the frequent pollution incidents, which seem unavoidable in the short term. On the other hand, environmental health risk is hard to manage.

Although the quality of the environment affects human health, the relation between certain diseases and the environment are multi-causal, multi-resultant and hysteretic. It's hard to determine whether a certain pollutant is the direct cause of a certain disease. Moreover, the cost of routinely monitoring pollutants related to people's health (called specific pollutants) is extremely high and even developed countries can hardly afford it.

To deal with this dilemma, Su says the authorities should pay more attention to health risk management in key regions, instead of focusing on overall emission-control measures. For instance, local authorities of Jiyuan in Henan province, the country's largest lead smelting base, should strictly monitor people's health in the villages around factories because they are susceptible to lead poisoning. It's a feasible way of monitoring the health of people at risk.

The base of China's environmental risk management is weak, but the authorities are working to strengthen it. Su and his colleagues are working on the position mark of heavy metal pollution in key regions, which can offer technical support to environmental risk management in some areas during the 12th Five-Year Plan period.