How the air quality bands are calculated
Band |
Index |
Ozone |
Nitrogen
Dioxide |
Sulphur
Dioxide |
PM2.5
Particles |
PM10
Particles |
Running 8
hourly mean |
Hourly
mean |
15 minute
mean |
24 hour
mean |
24 hour
mean |
µg m-3 |
µg m-3 |
µg m-3 |
µg m-3 |
µg m-3 |
Low |
|
|
1 |
0-33 |
0-67 |
0-88 |
0-11 |
0-16 |
2 |
34-66 |
68-134 |
89-177 |
12-23 |
17-33 |
3 |
67-100 |
135-200 |
178-266 |
24-35 |
34-50 |
Moderate |
|
|
4 |
101-120 |
201-267 |
267-354 |
36-41 |
51-58 |
5 |
121-140 |
268-334 |
355-443 |
42-47 |
59-66 |
6 |
141-160 |
335-400 |
444-532 |
48-53 |
67-75 |
High |
|
|
7 |
161-187 |
401-467 |
533-710 |
54-58 |
76-83 |
8 |
188-213 |
468-534 |
711-887 |
59-64 |
84-91 |
9 |
214-240 |
535-600 |
888-1064 |
65-70 |
92-100 |
Very High |
|
|
10 |
241 or more |
601 or more |
1065 or more |
71 or more |
101 or more |
Pollution concentrations recorded by the LAQN analysers have been classified according to Defra's
Air Pollution Index system. This classes levels into bands from 'low' to 'very high'. Each band is subdivided into three to produce
an Air Pollution Index, from 1 to 10, 1 being 'low', 10 being 'very high'. Measurements are rounded to the nearest whole number. The concentrations are classified according to
the table above. Note that different pollutants have different concentrations and averaging periods, related to the
estimated health effects of each. |
Read a technical explanation of how the new index bands (1st January 2012 onwards) are calculated here |
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