Following reports of a chemical stench last Monday (Sep 25) that was traced back to an industrial facility in Malaysia, it seems like the environment is once again giving Singaporeans some cause for concern.

Hazy conditions had been reported in parts of the island on Tuesday (Oct 3), prompting fears that forest fires were once again burning in neighbouring countries.

This was despite the 24-hour Pollutant Standards Index (PSI) and PM2.5 readings remaining in the moderate and normal range.

This time however, experts are pointing to local sources for the haze-like conditions. And the culprits are factories and cars.

In a quote carried by The Straits Times, air quality scientist Erik Velasco said: “The haze-like condition could have been due to the concentration of particle vapour and local emissions – from cars and factories.”

He ruled out the haze as being transboundary in nature.

In normal circumstances, these particles would disperse on their own, but cloudy conditions and “not too much wind” could have caused the area to appear hazy, according to Dr Velasco.

Responding to ST’s queries, the National Environment Agency (NEA) attributed the “slightly hazy conditions” on Tuesday morning to “an accumulation of particulate matter under light wind conditions”.

For more on this story, read The Straits Times.