Hong Kong Air Quality Readings
Below you will find the latest pollution readings from all of the Hong Kong Government’s official air quality monitoring stations. While there are 14 general ambient monitoring stations, only 3 of those 14 locations take roadside measurements – Central, Causeway Bay and Mong Kok.
CAN’s alert service shows measurements of nitrogen dioxide (NO2), particulate matter (PM), ozone and sulphur dioxide (SO2) for all the locations.
We compare actual, present levels of NO2, PM, ozone and SO2 to two standards:
- The Government’s Air Pollution Index (API) reading
- The World Health Organization’s Air Quality Guidelines (AQGs)
The ratio shows how far the WHO AQGs are being exceeded by current air pollution levels.
Even though the Government’s API is woefully out of date (not having been revised since 1987) and does NOT protect public health sufficiently by any stretch, we use the API level of 100 as a critical threshold above which to justify the issuance of the warning, “Avoid roadside situations.” Since the Air Quality Objectives, on which the API is based, are presently undergoing revision, we have chosen to take a conservative, uncontroversial approach – generous to the Government – and issue warnings in line with the EPD’s. However, please keep in mind that Hong Kong’s Air Quality Objectives, recommended maximum guidelines for 7 pollutants, permit pollutant levels 2-4 times greater than those recommended under the WHO AQGs.
Assessment of current pollutant levels against the WHO AQGs is provided on this page as well because these guidelines are considered by public health experts to be the best standards for adequate protection of public health. If you are interested to learn more about the AQGs, you can download the original WHO document here. It provides a comprehensive explanation of the AQGs.
It is crucial to note that, although pollutant levels are considered unsafe under the WHO AQGs, they may not result in an API reading in excess of 100. Again, CAN issues an avoidance warning ONLY when the Government API exceeds 100. However, this does not mean that it is healthy to be at the roadside when the API is under 100. Rather, one can only safely conclude that it is very unhealthy to go out when the API exceeds 100 and we have issued a warning. When the API is below 100 but pollution exceeds the WHO AQGs, you must make a judgment call for yourself about the advisability of venturing outside in a highly trafficked area.
| Kwai Chung | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 28 | 50 | 0.56 |
| Nitrogen Dioxide (NO2) | 44 | 200 | 0.22 |
| Ozone (O3) | 3.3 | 100 | 0.03 |
| Sulphur Dioxide | 85.4 | 20 | 4.27 |
| API: 29 | |||
WHO Air Quality Guideline
Current Reading
| Causeway Bay Roadside | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 22 | 50 | 0.44 |
| Nitrogen Dioxide (NO2) | 40 | 200 | 0.2 |
| Ozone (O3) | 0 | 100 | 0 |
| Sulphur Dioxide | 2.6 | 20 | 0.13 |
| API: 59 | |||
WHO Air Quality Guideline Current Reading
| Central Roadside | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 19 | 50 | 0.38 |
| Nitrogen Dioxide (NO2) | 41 | 200 | 0.21 |
| Ozone (O3) | 0 | 100 | 0 |
| Sulphur Dioxide | 0.0 | 20 | 0 |
| API: 39 | |||
WHO Air Quality Guideline Current Reading
| Central Western | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 12 | 50 | 0.24 |
| Nitrogen Dioxide (NO2) | 21 | 200 | 0.11 |
| Ozone (O3) | 15.3 | 100 | 0.15 |
| Sulphur Dioxide | 9.2 | 20 | 0.46 |
| API: 14 | |||
WHO Air Quality Guideline Current Reading
| Eastern | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 15 | 50 | 0.3 |
| Nitrogen Dioxide (NO2) | 19 | 200 | 0.1 |
| Ozone (O3) | 19.0 | 100 | 0.19 |
| Sulphur Dioxide | 3.9 | 20 | 0.2 |
| API: 18 | |||
WHO Air Quality Guideline Current Reading
| Kwun Tong | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 14 | 50 | 0.28 |
| Nitrogen Dioxide (NO2) | 31 | 200 | 0.16 |
| Ozone (O3) | 9.4 | 100 | 0.09 |
| Sulphur Dioxide | 4.5 | 20 | 0.23 |
| API: 32 | |||
WHO Air Quality Guideline Current Reading
| Mongkok Roadside | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 18 | 50 | 0.36 |
| Nitrogen Dioxide (NO2) | 41 | 200 | 0.21 |
| Ozone (O3) | 0 | 100 | 0 |
| Sulphur Dioxide | 12.1 | 20 | 0.61 |
| API: 51 | |||
WHO Air Quality Guideline Current Reading
| Sha Tin | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 12 | 50 | 0.24 |
| Nitrogen Dioxide (NO2) | 24 | 200 | 0.12 |
| Ozone (O3) | 14.5 | 100 | 0.15 |
| Sulphur Dioxide | 8.4 | 20 | 0.42 |
| API: 19 | |||
WHO Air Quality Guideline Current Reading
| Sham Shui Po | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 18 | 50 | 0.36 |
| Nitrogen Dioxide (NO2) | 37 | 200 | 0.19 |
| Ozone (O3) | 8.4 | 100 | 0.08 |
| Sulphur Dioxide | 11.3 | 20 | 0.57 |
| API: 27 | |||
WHO Air Quality Guideline Current Reading
| Tai Po | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 17 | 50 | 0.34 |
| Nitrogen Dioxide (NO2) | 22 | 200 | 0.11 |
| Ozone (O3) | 2.2 | 100 | 0.02 |
| Sulphur Dioxide | 6.6 | 20 | 0.33 |
| API: 24 | |||
WHO Air Quality Guideline Current Reading
| Tap Mun | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 14 | 50 | 0.28 |
| Nitrogen Dioxide (NO2) | 7 | 200 | 0.04 |
| Ozone (O3) | 31.4 | 100 | 0.31 |
| Sulphur Dioxide | 7.6 | 20 | 0.38 |
| API: 17 | |||
WHO Air Quality Guideline Current Reading
| Tsuen Wan | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 14 | 50 | 0.28 |
| Nitrogen Dioxide (NO2) | 20 | 200 | 0.1 |
| Ozone (O3) | 20.6 | 100 | 0.21 |
| Sulphur Dioxide | 6.6 | 20 | 0.33 |
| API: 29 | |||
WHO Air Quality Guideline Current Reading
| Tung Chung | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 14 | 50 | 0.28 |
| Nitrogen Dioxide (NO2) | 4 | 200 | 0.02 |
| Ozone (O3) | 41.0 | 100 | 0.41 |
| Sulphur Dioxide | 5.5 | 20 | 0.28 |
| API: 17 | |||
WHO Air Quality Guideline Current Reading
| Yuen Long | |||
| Current (A) | WHO AQG (B) | Ratio (A/B) | |
| Particulate Matter (PM10) | 23 | 50 | 0.46 |
| Nitrogen Dioxide (NO2) | 45 | 200 | 0.23 |
| Ozone (O3) | 2.0 | 100 | 0.02 |
| Sulphur Dioxide | 8.9 | 20 | 0.45 |
| API: 23 | |||
WHO Air Quality Guideline Current Reading
This is the 3rd time since moving here 4 years ago that I have found the API gov. website to not load on really, visibly heavy bad air pollution days. First time it was ignorable as a glitch, second time it was suspect, today it seems clearly a move to keep the numbers out of public hands and minds. Perhaps it is just coincidence, but it is starting to look like Beijing style information control. HK is a wonderful place and I really hope this is not part of a larger information censoring movement. Today–and many days– the air is at dangerous levels and I hope the responsible Government parties are honest enough to let the public know.