While the Pollution Control Department (PCD) on Wednesday reported lower PM2.5 dust particle amounts in nine northern provinces, several stations still cited dangerous levels.
Chiang Mai's Mae On district said it focused on creating the "safe zones" for the patient treatment and recuperation with the frequent spraying of water around hospitals.
Mae On district chief Suthep Saenmongkol said his district had dense haze so hospitals were being targeted to help patients.
As there are only four PCD air quality stations in Chiang Mai province, all in Muang and Mae Chaem districts, the PM2.5 level in Mae On was not released.
Mae On at 9am on Wednesday reportedly had 104.8 mcg - doubling the Thai safety limit of 50mcg.
The PCD 9am report said the nine northern provinces had PM2.5 particles ranging from 40 mcg to 130 mcg, which were all lower than the previous day.
The department, measuring 24-hour averages of PM2.5, put Tambon Wiang Phang Kham in Chiang Rai’s Mae Sai district at 130 mcg, followed by Tambon Jong Kham in Mae Hong Son’s Muang district at 67 mcg and Tambon Wiang of Chiang Rai’s Muang district at 59 mcg.