PolyU joins force with NASA to monitor air pollution at Pearl River Delta

Working in collaboration with the US National Aeronautics and Space Administration (NASA), The Hong Kong Polytechnic University (PolyU) is taking active steps to study the air pollution problem of the Pearl River Delta by analyzing the level of aerosols (atmospheric particles) with ground data and satellite images.

Sun Photometer Pointing at Sun and Taking Measurements A Sun photometer measures the intensity of sunlight arriving directly from the Sun. They are pointed directly at the Sun and measure direct sunlight. Since haze and aerosols block some direct sunlight, a Sun photometer is an ideal instrument for measuring haze. Credit: NASA

Under this collaborative agreement, PolyU is the first and the only one AERONET station in Hong Kong and the South China region. To support this development, PolyU researchers have already set up a satellite monitoring system on campus.

Dr Nichol further explained that aerosols, which are of different sizes and chemical composition, are reliable indicators of pollutant levels and visibility in a region. Previous studies showed that finest aerosol particles of less than 2.5 microns are hazardous to human health because they can penetrate deep into the lungs. These particles are airborne for a longer time because of their relatively small sizes.

"Our objective is to establish a relationship between satellite images and common pollutants such as Nitrogen Oxides and Sulphur Dioxides. In so doing, we can help regional authorities build up more accurate air quality models and pinpoint the major pollution sources affecting Hong Kong," she said.

To track down the level of aerosols in the region and their sources, PolyU researchers are now analyzing high-quality images from the Moderate-resolution Imaging Spectroradiometer (MODIS) on board NASA's satellite on a daily basis. The satellite measures both fine and coarse particles using different wavebands of the images. Moreover, the back trajectory function and regional coverage of MODIS images can help track down the emission sources as well as their magnitude.

The University has also purchased a brand new Sunphotometer to support this important study. The sophisticated instrument now operates during daylight hours, tracking the sun across the sky, and is able to measure the amount of aerosols in the atmosphere. The aerosols are measured in eight different wavebands corresponding to the wavebands of the MODIS satellite.

The project is supported by funding of PolyU's Faculty of Construction and Land Use. The ground data collected by PolyU will be uploaded to AERONET for research purposes. Mr Wong Man-sing, Site Manager and PhD student working on this project, has been recently named Fulbright-AIG Scholar.

Source / Credit: Hong Kong Polytechnic University / NASA