Application of Digital Camera Data for Air Quality Detection
H. S. Lim 1 , M. Z. MatJafri 2 , K. Abdullah 2 , Sultan AlSultan 3 and N. M. Saleh 4
1 Student, 2 Assoc. Prof. Dr., 4 Mr. School of Physics,
University of Science Malaysia,
11800 Penang, Malaysia
Email: mjafri@usm.my,
khirudd@usm.my
Tel: +604-6533888, Fax: +604-6579150
4 Dr., Al Sultan Environmental Research Center. Al Madina Rd., P.O.Box.
242 Riaydh Al Khabra, Al Qassim, Saudi Arabia.
Tel: +966504890977, Fax: +96663340366
Email: allssultan7@hotmail.com
ABSTRACT
Air pollution problem becomes increasingly critical in this present-day, whether in the developed or
developing countries. Air management is one of the important issues in this 21st century. Malaysia
is also affected by this problem. The new finding and analysis reported in this study provide a new
perspective of air quality detection. It can provide information highly useful for real-time modelling
of air quality. The objective of this study was to test the potential uses of digital camera imageries
for air quality detection. In-situ measurements of corresponding air pollution parameters were
carried out at the air pollution stations in Universiti Sains Malaysia, Penang. They were particulate
matter less than 10 micron (PM10) and CO. A semi-empirical relationship has been developed
between PM 10 and CO readings and the reflectance values recorded in visible bands by a normal
digital camera. The digital camera imageries were separated into three bands assigned as red, green
and blue bands for multispectral algorithm analysis. The best models were chosen based on the
highest correlation coefficient, R 2 and lowest root mean square error, RMS for PM10. This study
indicated that the digital camera imagery was capable of air quality estimation using remote sensing
technique.
1.0 INTRODUCTION
When the first measurements of high concentrations of CO over tropical Asia, Africa, and South
America were made available by the MAPS (Measurement of Air Pollution from Satellite)
instrument launched in 1981 on the space shuttle Columbia (1), it became clear that air pollution
was an international issue. Some studies showed that satellite data could be useful for revealing
climatic and environmental implications of global air pollution (Akimoto, 2003). PM 10 was chosen
as air quality parameter in this study.
But the main drawback of satellite images is the difficulty in obtaining cloud-free scenes
especially at the Equatorial region. This problem can be overcome by using airborne images. In
fact, air quality can be measured using ground instrument such as air sample. But these instruments
are quite expensive and limitation number of the air pollutant station of each area. So, they cannot
provide a detail spatial distribution of the air pollutant over a city. Several studies have shown the
possible relationships between satellite data and air pollution [Weber, et al., (2001) and Ung, et al,
(2001)].
The objective for this study was to test the use of a normal digital camera for air quality
detection. In-situ measurements of corresponding air pollution parameters were carried out at the
ASMA (Alam Sekitar Malaysia Sdn. Bhd.) air pollution station in Universiti Sains Malaysia,
Penang. They were needed for the analysis algorithm calibration. Only two-air quality parameters
were used in this study namely PM10 and CO. Various types of algorithm were tested and the
accuracy were noted.
