Shanghai officials propose real-time air quality index

A man on the Bund wears a mask Monday, as PM2.5 levels rose to more than double the national standard. (Zhang Suoqing)

The people of Shanghai will soon be able to better plan their outdoor activities if a proposal to introduce hourly updates for all major pollutants comes to fruition.  [Special coverage]

The plan is to give members of the public real-time access to PM2.5 and PM10 levels, said Fu Qingyan, chief engineer at the Shanghai Environmental Monitoring Center.

Under the current system — which calculates the average concentration of PM2.5 and PM10 over the previous 24 hours — the information is often out of date, she said.

"A real-time air quality index is much more useful, as the average does not take account of sudden changes in weather conditions, which can significantly affect air quality," she said.

For example, the real-time concentration of PM2.5 at a monitoring spot in Huangpu District at 2pm yesterday was 200.2 micrograms per cubic meter, while the average for the past 24 hours was just 138.5.

"With the new system, people will be able to make better decisions about whether or not to go out," Fu said.

The Shanghai Environmental Protection Bureau said it has been studying the new system for some time and has submitted its plans to the city government for approval.

Shanghai has 52 air quality monitoring spots across the city, and information about the concentration of the six pollutants — PM2.5, PM10, sulfur dioxide, nitrogen dioxide, ozone and carbon monoxide — collected from 10 main spots is published on the environmental monitoring center's website.

While readings for four of the pollutants are updated on an hourly basis, the PM2.5 and PM10 figures are given as the averages for the past 24 hours, in line with national standards.

PM2.5 and ozone are the most serious pollutants for Shanghai, with the former accounting for more than 70 percent of the polluted days recorded last year and ozone 26 percent.