The map markers indicate the positions of air quality monitoring stations,
and the color assigned to each marker corresponds to the air quality index recorded at that
specific station.
The index is determined by considering concentration values of up to five primary
pollutants, which include:
- Particulate matter (PM10)
- Fine particulate matter (PM2.5)
- Ozone (O3)
- Nitrogen dioxide (NO2)
- Sulphur dioxide (SO2)
The calculation of the AQ Index involves different methodologies for different pollutants. For
pollutants such as nitrogen dioxide (NO2), ozone (O3), and sulphur dioxide (SO2), the index
levels are based on hourly concentrations. This means that the concentration values for these
pollutants are measured and recorded on an hourly basis at the air quality monitoring
stations.
On the other hand, the AQ Index for particulate matter, specifically PM10 and PM2.5, is based on
daily running means. This means that the concentration values for these pollutants are
averaged
over a 24-hour period. The use of daily running means helps to smooth out the variations that
may occur throughout the day due to factors such as weather conditions, traffic patterns, and
human activities.
By considering both hourly concentrations for NO2, O3, and SO2, and daily running means for PM10
and PM2.5, the AQ Index methodology aims to provide a comprehensive and representative
assessment of air quality, enabling individuals and authorities to make informed decisions
regarding air pollution management and public health.
Bands of concentrations and index levels :
|
|
Good |
Fair |
Bad |
| O3 (ppm) |
≤ 100
|
100-240
|
≥ 240
|
| PM 2.5 (μg/m3) |
≤ 20
|
20-50
|
≥ 50
|
| PM 10 (μg/m3) |
≤ 40
|
40-100
|
≥ 100
|
| SO2 (ppm) |
≤ 100
|
100-200
|
≥ 200
|
| NO2 (ppm) |
≤ 90
|
90-230
|
≥ 230
|