Comparison of air quality between 2002 and 2003 in the area during the burning of rice straws in Mergong, Kedah

The practise of burning rice straws during the month of March usually causes air pollution within the vicinity of the paddy fields in Alor Star, Kedah. This is shown by hourly Air Pollutant Index (API) readings of more than 70 in March 2002. In addition, the levels of other air pollutants, such as carbon monoxide (CO), sulfur dioxide (SO2) and the suspended fine particulates of less than 10 microns (PM10) emitted into the air were also increased during the burning period. The evaluation of the air quality between March 2002 and 2003 showed that the maximum CO concentration was 1.03 ppm in 2003 in contrast to 1.43 ppm in 2002, while the maximum PM10 concentration in March 2003 was 208 μg/m3 compared with 312 μg/m3 in March 2002. The SO2 concentration recorded in 2002 was 0.006 ppm against a maximum of 0.013 ppm in March 2003. The statistical t-test for two samples assuming equal variances also supported these results which showed significant differences for the SO2 pollutant for the averaging period of 24 hours in contrast to the hourly readings which were not significantly different for the suspended particulate matter and gaseous CO and SO2.