Governments in the Pearl River Delta area have axed the decade-old regional air-quality index in favour of an online platform offering pollutant concentration readings that has been criticised as hard to understand.
The Environmental Protection Department announced the change in a press release yesterday after the environmental chiefs of Macau, Guangdong and Hong Kong signed an agreement on so-called “regional air-pollution control and prevention”.
The three governments agreed to do away with the index and a related map that used different colours to grade air quality across the region – a system in use since 2005 to monitor changes in air quality after a 2002 cross-border pact to reduce emissions.
After the termination of that index, there will no longer be a single yardstick covering the whole region. Rather, three different air-pollution indices and alert systems will now operate separately in Guangdong, Hong Kong and Macau.
The EPD hailed the new agreement as progress, with hourly updates of pollution readings at 23 locations in the region, including the newcomer Macau, via an online platform managed by the Guangdong authority.
The platform displays a map of the region, with the hourly concentration levels of six pollutants, such as ozone and fine particles, shown at each of the 23 selected monitoring locations: four in Hong Kong, one in Macau and the rest scattered around the Pearl River Delta.
However, Guangdong’s environmental protection bureau already releases hourly updates of air-quality data on its website (and has since 2012), covering 111 locations in the province and the same range of air pollutants.
Dr Cheng Luk-ki, the scientific and conservation head of the advocacy group Green Power, criticised the change as “a step backward” and a “loss of a common language in air pollution”.
He said that while the old index was compiled based on the national air-quality standards, it at least offered the readers clarity and meaningful comparisons of air-quality measurements across the region.
“The public will now find it hard to understand the meaning behind those pollution readings, without a simple index to explain the impacts,” he said.
He said the online platform was already redundant, as it made more sense for people to go directly to the air-quality index offered by their own local environmental authority.
Professor Wong Tze-wai, an air-pollution expert at the Chinese University of Hong Kong who helped devise the city’s new air-quality health index, said neither an “oversimplified index” nor “complicated pollution readings” would be meaningful to the public.
He said it would be beneficial if the air-quality indices between Hong Kong and the mainland could be unified, but he believed that would be a time-consuming process with many technical problems that would have to be overcome.
Hong Kong now employs an alert system that gives air-quality information by neighbourhood on a scale of one to 11, displaying the health risk associated with each reading.
Macau and Guangdong, meanwhile, use conventional air-quality index systems that express pollution as one of six grades, with scales from 0 to 500 and from 0 to more than 300.