The Pollution Control Department (PCD) put the readings between 24 and 46 micrograms of PM2.5 per cubic metre of air at 7am. The safe limit is 50.
It predicted a slight increase in pollution on Monday, but still within the safety limit.Rama II Road in Muang Samut Sakhon, one of the worst locations in the vicinity most days, had a reading of 33 micrograms on Sunday, down from 36 on Saturday and 81 on Friday.
Kanchanapisek Road in Bangkok's Bang Khun Thien district cited 46 micrograms, down from 52 on Saturday and 77 on Friday.
The Bangkok Metropolitan Administration (BMA) and other agencies staged "Big Cleaning Day" to sweep up dust on Rama III Road, with small aircraft spraying water from above and a mobile medical team giving people free check-ups.