Air quality almost reached unhealthy levels on Monday morning. The 24-hour Pollutant Standards Index reading was between 78 and 99, within the moderate range. A reading above 100 would indicate unhealthy air.

The one-hour PM2.5 concentration, a real-time gauge of air quality, hit 113 just before noon in a particular area. This measurement tracks tiny airborne particles over a single hour.

Further information on air quality readings and health advisories can be found on the National Environment Agency website. The public is advised to take precautions if the 24-hour PSI reading enters the unhealthy range, such as reducing outdoor physical exertion.