For the past few days most parts of peninsular Malaysia experience a hazy environment due to smog brought in by the South West Monsoon blowing from Sumatra. Satellite maps show hotspots and smoke blowing towards peninsular Malaysia,
Haze is a condition where there is a concentration of particles in the air causing health complications especially related to breathing. Small particles as small as 0.2 microns can enter the lungs and some of it is not water soluble and thus can deposit in the lungs.
It is advisable people working and doing activities in the open to wear mask for protection even though it is not 100% safe from inhaling those particles. But at least there is some safety precautions taken.