Particulate matter concentration levels inside public bus in Klang Valley / Mohd Luqman Hakimi Azmi

Particulate Matter exposure has been a concern in our daily lives such as our place of work, environment and home. The Department of Environment is responsible for controlling environmental pollution, while the Department of Occupational Safety and Health is responsible for exposures of workers in the workplace environment. However, less consideration has been given to the microenvironment we are living in such as public transportation and other places where we may be exposed to and where we spend some time. This study was done to measure the concentrations of the PM₁₀ and PM₂.₅ in the public bus transportation. The measurements were done by using TSI's DustTrak Aerosol Monitor and Quest EVM- 7 /CO Advanced Particulate and Air Quality Monitor with PID with logging interval of 30 second and run for 30 minutes each sample which represents the exposure time for the bus commuters. One way Anova was used to analyse the effects of travelling periods (morning: 8.00am-12.00pm and afternoon: 12.00-7.00pm) on the concentration of the particulate matter in buses. Post hoc analysis of Kramer Multiple Comparison was used to analyse the groups involved. Independent t-test was used to analyse types of bus as a factor that contributed to the high concentration of particulate matter. Descriptive data and inferential data showed that both PM₁₀ and PM₂.₅ are affected by the type of bus and the travelling period. The study found that the highest exposure for both PM₁₀ and PM₂.₅ are at the morning peak time for the Metro Bus (n=24) with PM₁₀ mean exposure=198.8± .... µg/m³ and PM₂.₅=67.08±20.73µg/m³ while for Rapid KL (n=26) the PM₁₀=156.54±35.21 µg/m³ and PM₂.₅=41.81±7.54µg/m³. One way Anova result (p<0.001) with significance difference (p<0.05) between AM Peak travelling time and the PM peak travelling period. Independent t-test (p<0.001) showed a significance difference (p<0.05) between Rapid KL Bus and Metro Bus for both PM₁₀ (mean difference=198.8±5.63µg/m³) and PM₂.₅ (mean difference=97.6±5.771µg/m³) concentrations. This phenomenon could be due to the microclimate inversions and high density of PM concentrations in the micro­ environment. In Malaysia there are no specific legislation on the concentration of particulate matter in vehicles for PM₁₀ and PM₂.₅. However as a working place for the drivers the USECCHS, Regulations 2000 was complied with PM₁₀=3mg/m³ and no standards set for PM₂.₅