SINGAPORE - Singapore experienced slightly hazy conditions yesterday, when the three-hour Pollutant Standards Index (PSI) average hit 50 at 3pm and stayed in the moderate range till evening.
A PSI reading of 50 and below indicates that the air quality is "good", while anything above 50 is "moderate" and above 100 is considered "unhealthy".
While the three-hour PSI reading went down to 42 by 12 noon today, a health advisory on the National Environmental Agency's (NEA) website said Singapore is still expected to experience hazy conditions on some days of this week.
This is as the current spell of dry weather is aggravating hot spot activities in southern Sumatra.
The Straits Times reported that National Aeronautics and Space Administration (NASA) satellites have picked up fire activities in both southern Sumatra and Kalimantan.
The annual haze is typically caused by farmers and logging companies burning forest areas to clear land for cultivation. The wind blowing from these countries towards Singapore brings the smoke here.
For the coming week, the increase in hotspot activities combined with the low level winds blowing from the southeast or southwest is expected to result in hazy conditions here, NEA said.
The impact of the smoke haze in Singapore is dependent on factors such as the proximity and extent of the fires, the strength and direction of the prevailing winds and the incidence and amount of rain.