The 3-hr PSI moving average is really somewhat slow. The conditions here down south + my PM2.5 monitor has been steady since about 9+AM (my above post was 8.49am visual sighting), but 2PM 3-hr PSI moving average is still rising. In fact now 2+PM I think conditions have improved quite a bit.
I am sure most folks wouldn't wanna be swimming (hot weather) for 1 to 1.5hrs for 20 laps out in this kind of air.
NEA reported that they will do 1-hr NEA readings, but it's still not yet implemented as of now. Check the source from nea.gov.sg, the info is all there with regards to 1-hr readings.
Like what China and the US Embassy have been doing, and yes they also report 24-hr etc.
My PM2.5 monitor is sometimes spiking up and down depending on wind speed.
Eg
Beijing PM2.5-Beijing AQI-China PM2.5
Main Air Pollutants: PM2.5
Health Implications:Air quality is acceptable, but maybe unhealthy to a small number of sensitive groups.
Beijing PM2.5
1-hour PM2.5: 73.92μg/m3,
24-hour PM2.5: 37.62μg/m3.
1-hour PM2.5 ranks #127 in China by ascending,total 190 cities.
1-hour PM10: 145.17μg/m3,
24-hour PM10: 88.07μg/m3.