Although he has been retired for more than two decades, 88-year-old academician Wang Wenxing has not stopped nurturing talent in environmental protection and promoting research of air pollution sources.

His study of sulfur dioxide emissions and suggestions on controlling acid rain have played an important part in the reduction of air pollution nationwide, said Wang's colleague Chai Fahe, deputy director of the Chinese Research Academy of Environmental Sciences.

The concentration of major air pollutants like PM2.5 and nitrogen dioxide has been much higher than the national standards in many cities, resulting in numerous smoggy days.

Reducing these airborne pollutants has been a priority of both central and local governments since last year, but pollution is still a problem for many governments.

But sulfur dioxide, a major airborne pollutant, has been an exception. Many cities already are in compliance with national standards that govern how much of the pollutant can be in the air.

For example, the concentration of sulfur dioxide in Beijing was reduced by 82 percent from 1998 to 2014. Sulfur dioxide is the only air pollutant in the capital whose level meets national standards, according to a report released by the municipal Environmental Protection Bureau.

As one of the pioneers of the domestic study of atmospheric environmental chemistry, Wang has contributed to the efficient control of sulfur dioxide and acid rain, which has been widely accepted in the research academy, where he has worked for 35 years, as well as in the national atmosphere field.

From 1982 to 1985, Wang was in charge of the field research in a three-year scientific project on sulfur dioxide and particle matter analysis. It was the largest project in the early research of air pollution.

"I can still recall the field work undertaken at that time when we spent months in the wild. It was tiring but worth it," Wang said.

The team deployed more than 730 instruments, 47 radar systems and three airplanes, to monitor the pollutants. They were using the most advanced technology at that time.

The data collected in the project helped the researchers draw up the rules of air pollutants, including their distribution and transfer, and provided the solid theoretical groundwork for efforts to control air pollution and acid rain.

After that, he continued his research on acid rain for 15 years to build the monitoring network that covered almost the whole country.

Thanks to Wang's research and suggestions, China did not have the severe effects of acid rain that many Western countries did, including dead fish and deteriorating water quality in rivers and lakes, said Chai, of the Chinese Research Academy of Environmental Sciences.

After Wang's retirement in 1993, he continued to further his studies with young researchers. In 2005, he became head of the Environmental Research Institute of Shandong University, from which he had graduated in 1952.

In addition, he set up a scholarship for students in the Chinese Research Academy of Environmental Sciences with his personal salary, and has supported 27 students since 2006.

"I came from a poor family in a rural area, and it's the country that helped me to finish my study, so it's my turn to help others in need," he said.