The National Environmental Board redefined what unhealthy air is, setting a new threshold for fine dust that will take effect June 1.
Attapon Charoenchansa, director-general of the Pollution Control Department, said the National Environmental Board updated the safety threshold for particulate matter 2.5 micrometers and smaller in diameter to suit present circumstances because it had been established more than decade ago.
The old threshold of PM2.5 was set at 50 micrograms a cubic meter of air in 24 hours. The new standard will be 37.5 mcg.
The board also changed the annual safety threshold from 25 mcg. to 15 mcg. That will take effect in a few months, Attapon said.
The updated air-quality standard would be as in the United States, European Union, South Korea, Japan, Singapore, Malaysia and Taiwan, he said.
Of course, redefining what unhealthy air is does nothing to actually make it healthier. The PCD offered no plans on how to accomplish that more important task.