|
Retrieval of PM10 from ADOES Data Study Area The study area is Penang island, located between latitudes 5° 12’ N to 5° 30’ N and longitudes 100° 09’ E to 100° 26’ E as shown in Figure 1. The AVNIR satellite image captured on 17 March 1997 was used in the present application.  Figure. 1. The location of the study area Data Analysis and Results The PCI EASI/PACE version 9.1 digital image processing software was used in all image-processing analyses. The algorithm used in this study is given in equation 1. The surface reflectance was subtracted from the apparent reflectance to obtain the atmospheric component of the image. The surface reflectance values for these three visible wavelengths were determined based on the Landsat TM data. The Landsat TM data was atmospheric corrected using ATCOR2 in the PCI Geomatica image processing software. The atmospheric reflectance was used for determine PM10 values used previously Landsat TM algorithm regression coefficient. A PM10 map was generated using the proposed algorithm and colour-coded for visual interpretation (Figure 2). 
where P = PM10 concentration and Ratmi = Atmospheric reflectance for band i  Figure 2. Map of PM10 around Penang Island, Malaysia (Blue < 40 mg/m3, Green = (40-60) mg/m3, Yellow = (60-80) mg/m3, Orange = (60-80) mg/m3 and Red >80 mg/m3 and White = cloud and water areas) Conclusion This study indicated that the previously calibrated algorithm could be used to generated PM10 using AVNIR data. AVNIR can provide a useful tool for air pollution mapping around Penang Island. The coincident in situ PM10 data must be collected for further analysis. The feasibility of applying the present technique for operational use has to be further validated. Therefore more data will be required for this verification analysis. |