 |
API Subindex
Levels and Their Corresponding Concentrations
|
API
Subindex Level
|
Relationship
with HKAQO
|
Corresponding
Concentrations (µg/m3)
|
|
RSP
24-hr
|
SO2
24-hr
|
SO2
1-hr
|
NO2
24-hr
|
NO2
1-hr
|
CO
8-hr
|
CO
1-hr
|
O3
1-hr
|
|
0
|
-
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
25
|
50% Annual
HKAQO / 25% HKAQO
|
28
|
40
|
200
|
40
|
75
|
2500
|
7500
|
60
|
|
50
|
Annual
HKAQO / 50% HKAQO
|
55
|
80
|
400
|
80
|
150
|
5000
|
15000
|
120
|
|
100
|
HKAQO
|
180
|
350
|
800
|
150
|
300
|
10000
|
30000
|
240
|
|
200
|
-
|
350
|
800
|
1600
|
280
|
1130
|
17000
|
60000
|
400
|
|
300
|
-
|
420
|
1600
|
2400
|
565
|
2260
|
34000
|
90000
|
800
|
|
400
|
-
|
500
|
2100
|
3200
|
750
|
3000
|
46000
|
120000
|
1000
|
|
500
|
-
|
600
|
2620
|
4000
|
940
|
3750
|
57000
|
150000
|
1200
|
|
|
|