Bangkok (NNT/VNA) - Overall air quality remained at unhealthy levels in northern Thailand, particularly in the provinces of Phrae and Phayao, as of February 18.

In Bangkok and neighbouring provinces, the concentration of dust particles rose but was within safety limits.

The Pollution Control Department advised that levels of particulate matter of 2.5 microns or less (PM2.5) in the air in greater Bangkok measured between 12 and 31 micrograms per cubic meter. The PM2.5 levels increased at almost all air-monitoring stations, but they remained below the danger level, set at 50 micrograms per cubic meter. People can still engage in outdoor activities at this time.

In the North, air quality ranged from moderate to unhealthy. Fine dust pollution exceeded the safety threshold in a number of areas, including Mae Sot district in Tak province, Muang Nan and Chaloem Phra Kiat districts in Nan province, Muang Phayao district in Phayao province, Muang Lampang and Mae Moh districts in Lampang province, Muang Lamphun district in Lamphun province, Muang Chiang Rai and Mae Sai districts in Chiang Rai province, Muang Chiang Mai and Mae Chaem districts in Chiang Mai province, Muang Phrae district in Phrae province and Muang Mae Hong Son district in Mae Hong Son province./.