A 3D aerosol and visibility information system for urban areas using remote sensing and GIS

Nowadays many location-based many services and information are provided to urban residents using internet or mobile phones. So far you can get the locations of nearby streets, buildings, and other facilities, weather information and traffic conditions However although air quality is so important to our lives and health, we cannot get local air quality information.

This project uses satellite images from NASA’s MODIS satellite sensor, along with an AERONET sunphotometer stationed on PolyU roof (see figure below) to give air quality and visibility information by street an building location across Kowloon, in 3D. The system operates in near-real time because although MODIS only passes over Hong Kong twice a day, AERONET operates every 15 minutes.

 

 

Below is an image from MODIS showing Aerosol Optical Thickness (AOT) on October 20th 2007 at 500m resolution. AOT levels above 1 are common in Hong Kong but rare in many cities in Europe and America.

 

Below is an aerosol and visibility information system output for West Kowloon for mornings of 1st (a) and 4th February (b)  2007 showing result of a query for Floors 115 and 15 of the International Commerce Centre. Aerosol levels decrease with increasing elevation, from brown (highest) to blue (lowest), and are higher on 1st February a weekday, than on 4th February, a weekend.The square aerosol blocks correpond to the MODIS satellite pixels.