sulfur dioxide 60ppb
AQI 82
moderate · bad
sulfur dioxide 60 ppb — AQI 82
sulfur dioxide at 60 ppb scores 82 on the US index, and the Korean grade calls it bad.
The two systems disagree here
- Concentration
- 60 ppb
- US index (AQI)
- 82
- US category
- moderate
- Korean grade
- bad
- Concentration that makes 100
- 75 ppb
Same number, different verdict
A Korean forecast calls PM10 of 150 "bad", but the same value in the US index is 98 — still moderate. The other way round, PM2.5 of 40 has only just crossed into "bad" in Korea while the US index already reads 112, unhealthy for sensitive groups. Neither is wrong; they hold different rulers. Move country and the same air reads differently.
Nearby cells
Same pollutant, other concentrations
How to read this
- On the left is the US index, on the right the Korean grade — the same concentration measured with two rulers.
- Index values of 50, 100 and 150 are the boundaries; that is where the category name changes.
- Forecast grades are usually daily averages, not the reading at this moment.
- The cigarette figure is only for PM2.5 and assumes a full day of exposure.
Frequently asked questions
Q. How bad is sulfur dioxide at 60 ppb?
82 on the US index, and bad on the Korean scale.
Q. Do the two systems agree?
No — this is one of the places where one calls it moderate and the other calls it bad.
Q. What concentration would make the index 100?
75 ppb. This page is at 60 ppb.
Q. What is this pollutant?
sulfur dioxide. The cigarette comparison is only applied to PM2.5.