Health
What the public guidance actually says about a body — sleep, food, teeth, air — with the numbers, and without turning any of it into advice.
- The AQI is a definition: China vs US breakpoints Health·2026-10-12 ·8 min read
One PM2.5 concentration, two index numbers. How China's HJ 633—2026 and the US breakpoints are built, and what GB 2626 and NIOSH require.
- China's national sleep averages do not agree Health·2026-10-12 ·11 min read
Chinese sources put average night sleep for the whole country between 6.85 and 7.84 hours, a year apart. The spread is sampling, instrument and definition.
- Oral care: what the official guidance says Health·2026-10-12 ·9 min read
Brushing, fluoride strength, floss versus water flossers, and professional cleaning — the wording from Chinese, US and UK bodies, with dates.
- Where the sleep-duration numbers come from Health·2026-10-12 ·9 min read
Seven hours, nine hours, a range per age group — the figures all trace back to four papers and a few government notices, and to how firm each is.