## Air Pollution Index levels scale ### Overview Different countries have their own air quality indices, corresponding to different national air quality standards. Please find air quality index levels scales used in [UK,](#uk) [Europe,](#europe) [USA](#usa) and [Mainland China](#china) in the sections below. You can get air pollution data for any coordinates on the globe using [Air Pollution API](/api/air-pollution.md). ## Air quality index levels scale in UK Below is a description of UK Air Quality Index levels: | Qualitative name | Index | Pollutant concentration in μg/m3 | | | | | | --- | --- | --- | --- | --- | --- | --- | | | | SO2 | NO2 | PM2.5 | PM10 | O3 | | Low | 1 | 0-88 | 0-67 | 0-11 | 0-16 | 0-33 | | Low | 2 | 89-177 | 68-134 | 12-23 | 17-33 | 34-66 | | Low | 3 | 178-266 | 135-200 | 24-35 | 34-50 | 67-100 | | Moderate | 4 | 267-354 | 201-267 | 36-41 | 52-58 | 101-120 | | Moderate | 5 | 355-443 | 268-334 | 42-47 | 59-66 | 121-140 | | Moderate | 6 | 444-532 | 335-400 | 48-53 | 67-75 | 141-160 | | High | 7 | 533-710 | 401-467 | 54-58 | 76-83 | 161-187 | | High | 8 | 711-887 | 468-534 | 59-64 | 84-91 | 188-213 | | High | 9 | 888-1064 | 535-600 | 65-70 | 92-100 | 214-240 | | Very High | 10 | ⩾1065 | ⩾601 | ⩾71 | ⩾101 | ⩾241 | ## Air quality index levels scale in Europe Below is a description of Europe Air Quality Index levels: | Qualitative name | Index or sub-index | Pollutant (hourly) concentration in μg/m3 | | | | | --- | --- | --- | --- | --- | --- | | | | NO2 | PM10 | O3 | PM2.5 | | Very Low | 0-25 | 0-50 | 0-25 | 0-60 | 0-15 | | Low | 25-50 | 50-100 | 25-50 | 60-120 | 15-30 | | Medium | 50-75 | 100-200 | 50-90 | 120-180 | 30-55 | | High | 75-100 | 200-400 | 90-180 | 180-240 | 55-110 | | Very high | >100 | >400 | >180 | >240 | >110 | ## Air quality index levels scale in USA Below is a description of USA Air Quality Index levels: | AQI | Level of health concern | Color | | --- | --- | --- | | 0 to 50 | Good | Green | | 51 to 100 | Moderate | Yellow | | 101 to 150 | Unhealthy for sensitive groups | Orange | | 151 - 200 | Unhealthy | Red | | 201-300 | Very unhealthy | Purple | | 301-500 | Hazardous | Maroon | | 501-1000 | Very Hazardous | Brown | For pollutants concentration recalculation into AQI equation and table below is used:  where: I = the Air Quality index, C = the pollutant concentration, Clow= the concentration breakpoint that is ≤C, Chigh= the concentration breakpoint that is ≥C, Ilow= the index breakpoint corresponding to Clow, Ihigh= the index breakpoint corresponding to Chigh. | Ilow-Ihigh | O3, ppb (8-hr) | O3, ppb (1-hr) | PM2.5, μg/m3 (24-hr) | PM10, μg/m3 (24-hr) | CO, ppm (8-hr) | SO2, ppb | NO2, ppb (1-hr) | | --- | --- | --- | --- | --- | --- | --- | --- | | Сlow-Chigh(avg) | | | | | | | | | 0-50 | 0-54 | - | 0.0-12.0 | 0-54 | 0.0-4.4 | 0-35 (1-hr) | 0-53 | | 51-100 | 55-70 | - | 12.1-35.4 | 55-154 | 4.5-9.4 | 36-75 (1-hr) | 54-100 | | 101-150 | 71-85 | 125-164 | 35.5-55.4 | 155-254 | 9.5-12.4 | 76-185 (1-hr) | 101-360 | | 151-200 | 86-105 | 165-204 | 55.5-150.4 | 255-354 | 12.5-15.4 | 186-304 (1-hr) | 361-649 | | 201-300 | 106-200 | 205-404 | 150.5-250.4 | 355-424 | 15.5-30.4 | 305-604 (24-hr) | 650-1249 | | 301-400 | - | 405-504 | 250.5-350.4 | 425-504 | 30.5-40.4 | 605-804 (24-hr) | 1250-1649 | | 401-500 | - | 505-604 | 350.5-500.4 | 505-604 | 40.5-50.4 | 805-1004 (24-hr) | 1650-2049 | ## Air quality index levels scale in Mainland China Below is a description of Mainland China Air Quality Index levels: | AQI | Air pollution level | Air pollution category | | --- | --- | --- | | 0-50 | Level 1 | Excellent | | 51-100 | Level 2 | Good | | 101-150 | Level 3 | Lightly polluted | | 151-200 | Level 4 | Moderatory polluted | | 201-300 | Level 5 | Heavily polluted | | >300 | Level 6 | Severely polluted | An individual score (Individual Air Quality Index, IAQI) is calculated using formula and table with breakpoint concentrations below:  where: I = the Individual Air Quality index, C = the pollutant concentration, Clow= the concentration breakpoint that is ≤C, Chigh= the concentration breakpoint that is ≥C, Ilow= the index breakpoint corresponding to Clow, Ihigh= the index breakpoint corresponding to Chigh. | Individual index | Units are in μg/m3 except CO, which is in mg/m3 | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | IAQI | SO2, 24 hour | SO2,1 hour (1) | NO2, 24 hour | NO2, 1 hour (1) | PM10, 24 hour | CO, 24 hour | CO, 1 hour (1) | O3, 1 hour | O3, 8 hour | PM2.5, 24 hour | | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | 50 | 50 | 150 | 40 | 100 | 50 | 2 | 5 | 160 | 100 | 35 | | 100 | 150 | 500 | 80 | 200 | 150 | 4 | 10 | 200 | 160 | 75 | | 150 | 475 | 650 | 180 | 700 | 250 | 14 | 35 | 300 | 215 | 115 | | 200 | 800 | 800 | 280 | 1200 | 350 | 24 | 60 | 400 | 265 | 150 | | 300 | 1600 | (2) | 565 | 2340 | 420 | 36 | 90 | 800 | 800 | 250 | | 400 | 2100 | (2) | 750 | 3090 | 500 | 48 | 120 | 1000 | (3) | 350 | | 500 | 2620 | (2) | 940 | 3840 | 600 | 60 | 150 | 1200 | (3) | 500 | | Notes | (1) SO2, NO2, CO 1 hour average concentrations are only for real time reporting. For daily reports use 24 hour average concentration. (2) If the SO2 concentration exceeds 800 μg/m3 use the index from the 24 hour concentration instead. (3) If the O3 concentration exceeds 800 μg/m3 use the index from the 1 hour concentration instead. | | | | | | | | | |