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SCMP Reporter

Hong Kong and Guangdong could launch a satellite of their own to monitor air quality and make pollution forecasts for the region, a university specialist in geographical information systems has suggested.
The idea was floated by Professor Janet Nichol, a geoinformatics  expert at Polytechnic University who has used data from two Nasa satellites to gauge the concentration of fine particles in the air. Geoinformatics develops and uses scientific information  to address the problems of geography, geosciences and  engineering.
The satellite information complements data recorded at five ground-level monitoring stations.
According to one of the Nasa maps based on data recorded on January 28, 2007, most fine particles, also known as PM2.5, were clustered  in the urban areas. 
But the particle concentrations on Chek Lap Kok, Kwai Chung container port and Disneyland were most noticeable. Across the border in Shekou, concentrations also peaked at between 80 and 100 micrograms per cubic metre of air.
However, another map, for January 10 this year, found concentrations in the urban area  generally lower than  in 2007. But high concentrations occurred at the airport and Shekou.  
The new air quality objectives for fine particles proposed by the government set the 24-hour average at about 75mcg of particles per cubic metre of air. 
Currently, there is no standard for PM2.5 in Hong Kong, though the Environmental Protection Department takes informal measurements at five locations. Fine particles are believed to have more health-threatening effects than larger particles because they can penetrate deep into the lungs or even blood vessels.
Nichol said the maps were just 'snapshots' and could not explain fully the pollution phenomenon.
Despite that, she said, a satellite could offer a visual and spatial perspective, which the existing location-based monitoring network could not, and that could help track the movement of pollutants.
With enough images and funding, she said, a forecast system could be developed capable of giving prior warning on air pollution. A similar system is also being developed in Texas in the US. Nasa satellites can supply two or  three images a day, but the US space agency is planning to launch a new satellite in early 2011 that could yield up to six images daily.
But an orbiting satellite might not be the best solution because it could only pass a given location two or three times a day. 'One alternative is to use a satellite able to stay in one point,'  Nichol said. 'Japan has its own satellite sending back images every half an hour.'
She said use of satellite images in researching air quality was a growing trend and, as satellites became smaller and cheaper, many more nations or cities could afford their own.
'Maybe in the next five or six years, it would be possible for Hong Kong and Guangdong to install a stationary satellite' able to measure air quality, she said.
Launching an 80cm satellite and setting up a signal-receiving facility could cost as little as US$10 million. Nichol said that the Nasa images would be  enough to develop the forecast system in four years, at a cost of about HK$1.4 million. 
 But she said her idea seemed not to have been well received by environmental officials.
'The Environmental Protection Department  seems to be reluctant to adopt new technology, though the Hong Kong Observatory  is quite positive and receptive,' she said.
Nichol said her  team would seek funding from the university's general research grant and hoped to build a partnership with the Observatory and overseas agencies. 
Using the Nasa images, Nichol has also been producing maps to research the heat-island effect in the city since 2005.



Scientist proposes shared delta satellite to monitor air quality