The decline of pesticide residues in the air of three rain shelter farms at Cameron Highlands

Field experiments in three commercial farms in Cameron Highlands were conducted to study the decline in time in the concentration of pesticide residues in air for a non-volatile compound (Cypermethrin) and a moderately volatile compound (chlorpyrifos). The concentrations of the compounds in air were monitored for three days (72 hours) after the pesticide application. The maximum concentration of chlorpyrifos found was 8.9 µg/m^3 . Cypermethrin residue was not traceable throughout the studies. After a dissipation period of several hours, chlorpyrifos concentration in the air was rapidly decreased to more than 50% of its initial concentration. By using Single Factor ANOVA analysis, no significant differences in residue concentration were found between samples collected at 0.5 m and 1.6 m heights. Higher concentration of chlorpyrifos residues was observed in the farm with rain shelter and side netting.