Air quality·coarse dust PM10 40
coarse dust PM10 40µg/m³
AQI 37
good · moderate

coarse dust PM10 40 µg/m³ — AQI 37

coarse dust PM10 at 40 µg/m³ scores 37 on the US index, and the Korean grade calls it moderate.

Both systems agree here

Concentration
40 µg/m³
US index (AQI)
37
US category
good
Korean grade
moderate
Concentration that makes 100
154 µg/m³

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

30 µg/m³
AQI 28
50 µg/m³
AQI 46

Same pollutant, other concentrations

10 µg/m³
AQI 9
20 µg/m³
AQI 19
30 µg/m³
AQI 28
40 µg/m³
AQI 37
50 µg/m³
AQI 46
60 µg/m³
AQI 54
80 µg/m³
AQI 64
100 µg/m³
AQI 74
120 µg/m³
AQI 83
150 µg/m³
AQI 98
180 µg/m³
AQI 114
200 µg/m³
AQI 124
250 µg/m³
AQI 148
300 µg/m³
AQI 174
350 µg/m³
AQI 198
400 µg/m³
AQI 266
450 µg/m³
AQI 330
500 µg/m³
AQI 385

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 coarse dust PM10 at 40 µg/m³?

37 on the US index, and moderate on the Korean scale.

Q. Do the two systems agree?

Yes, both read it the same way here.

Q. What concentration would make the index 100?

154 µg/m³. This page is at 40 µg/m³.

Q. What is this pollutant?

coarse dust PM10. The cigarette comparison is only applied to PM2.5.