City report · Hong Kong
Hong Kong Air quality today
Air quality in Hong Kong currently reads AQI 63 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
AQI 63
Air quality right now
Moderate
- PM2.5, fine particles (µg/m³)
- 15.4
- tree cover
- 50.9%
- trees in this area
- 109K
- more trees needed
- 0
Measured across a 2 km radius around Wan Chai, Hong Kong Island, Hong Kong (12.57 km²), from a satellite image of Aug 8, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Hong Kong · AQI 63 (Moderate)
Hong Kong's tree count comes to 108,897 trees across 8.56 km² of land, already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Hong Kong today: AQI 63, Moderate
Main pollutant: PM2.5 · Observed Nov 12, 00:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Causeway Bay, 1.1 km away · median of 7 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
15.4
PM10
25.4
NO₂
64.8
O₃
59.6
SO₂
2.9
CO
479.5
Data: OpenAQ · Hong Kong, Environmental Protection Department, HKSAR Government · DATA.GOV.HK
- Outdoor exercise
- Fine for most people; unusually sensitive people should take long or hard exercise easier
- Windows
- Fine to open; close them if you are sensitive to pollution
- Mask
- Not needed for most people
- Air purifier
- Worth running if you are sensitive
Over the last 7 days, the CAMS air-quality model put Hong Kong's daily AQI at 81 on average, from 62 on Nov 9 to an hourly peak of 235 on Nov 6.
This is the US EPA AQI. How it differs from Hong Kong's AQHI
Where Hong Kong stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Hong Kong: Healthy tree cover
50.9% tree cover against a 30% healthy-neighborhood target, across 8.56 km² of land.
Trees in this area
108,897
Target trees
108,897
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Hong Kong lost?
Since 2001, the area within 10 km of Hong Kong has lost about 102 hectares of forest (about 140 football pitches): 1.2% of the forest it had in 2000. Most of it (82%) was deforestation, forest cleared for good, mainly for towns and roads.
2018: satellite photo from October 2018 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 102 haabout 140 football pitches
- Share of its forest
- 1.2%of what there was in 2000
- Cleared for good
- 83 hadeforestation: turned into farms, mines or towns
The worst year was 2009, when about 16 hectares of forest were lost.
Hectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | under 1 ha | under 1 ha | under 1 ha |
| 2002 | 7 ha | under 1 ha | 7 ha |
| 2003 | 5 ha | under 1 ha | 5 ha |
| 2004 | 10 ha | under 1 ha | 11 ha |
| 2005 | under 1 ha | under 1 ha | 2 ha |
| 2006 | 1 ha | under 1 ha | 2 ha |
| 2007 | 7 ha | under 1 ha | 7 ha |
| 2008 | 7 ha | 1 ha | 8 ha |
| 2009 | 15 ha | 1 ha | 16 ha |
| 2010 | under 1 ha | under 1 ha | 1 ha |
| 2011 | 2 ha | under 1 ha | 2 ha |
| 2012 | under 1 ha | under 1 ha | 1 ha |
| 2013 | under 1 ha | under 1 ha | under 1 ha |
| 2014 | under 1 ha | under 1 ha | under 1 ha |
| 2015 | 1 ha | under 1 ha | 1 ha |
| 2016 | 1 ha | under 1 ha | 1 ha |
| 2017 | 4 ha | under 1 ha | 5 ha |
| 2018 | 3 ha | 1 ha | 4 ha |
| 2019 | 2 ha | under 1 ha | 2 ha |
| 2020 | under 1 ha | under 1 ha | under 1 ha |
| 2021 | 5 ha | 4 ha | 9 ha |
| 2022 | 2 ha | under 1 ha | 2 ha |
| 2023 | 5 ha | 3 ha | 8 ha |
| 2024 | under 1 ha | under 1 ha | under 1 ha |
| 2025 | 2 ha | under 1 ha | 3 ha |
What is causing deforestation around Hong Kong?
- Towns and roadscleared for good82% · 83 ha
- Wildfirescan grow back4.1% · 4 ha
- Storms, floods and other natural causescan grow back2.6% · 3 ha
Also: unknown causes.
Causes for 2025 are estimates, based on what caused forest loss in the same places up to 2024.
Forest gained and lost, 2000–2020
- Forest in 2000
- 9,430 ha
- Forest in 2020
- 9,440 ha
- Overall change
- +8 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Hong Kong stayed about the same size, at about 9,440 hectares: new forest grew on about 123 hectares, and about 115 hectares were lost.
These 2000 and 2020 maps, from the University of Maryland, count any land with trees taller than 5 m as forest, including plantations and orchards. Forest that was cut or burned and had grown back by 2020 counts in both years, so the loss here is smaller than the yearly figures.
These figures cover everything within 10 km of the city center, a wider area than the report above, because forest is usually lost at a city's edges.
Source: Hansen/UMD/Google/USGS/NASA, Global Forest Change (GFC-2025-v1.13); causes: WRI/Google DeepMind drivers of forest loss; both CC BY 4.0, summed by Airleaf for each area. Forest gained and lost 2000–2020: Potapov et al. 2022, UMD GLAD Global Land Cover and Land Use Change, CC BY 4.0. Images: contains modified Copernicus Sentinel data. How it's measured
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Frequently asked
Questions about Hong Kong
What is the air quality (AQI) in Hong Kong right now?
The latest reading for Hong Kong shows an AQI of 63 (Moderate), measured Nov 12, 00:00 local time by 7 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Causeway Bay, 1.1 km away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Hong Kong today?
At AQI 63 (Moderate): fine for most people; unusually sensitive people should take long or hard exercise easier. Windows: fine to open; close them if you are sensitive to pollution. Masks: not needed for most people. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Hong Kong been like this week?
Over the last 7 days, the CAMS air-quality model put Hong Kong's daily AQI at 81 on average, from 62 on Nov 9 to an hourly peak of 235 on Nov 6. On 1 of those days the average was above 100, unhealthy for sensitive groups.
Is Hong Kong's AQI the same as Hong Kong's AQHI?
No. Airleaf shows the US EPA Air Quality Index (AQI), the scale used by IQAir and most air-quality apps. Hong Kong's Environmental Protection Department publishes the Air Quality Health Index (AQHI) on a 1 to 10+ scale: 1–3 low, 4–6 moderate, 7 high, 8–10 very high and 10+ serious. It is a health-risk scale built from short-term pollutant levels, not a converted AQI, so the two numbers can't be compared directly.
How much forest has the area around Hong Kong lost since 2001?
Since 2001, the area within 10 km of Hong Kong has lost about 102 hectares of forest (about 140 football pitches): 1.2% of the forest it had in 2000. Most of it (82%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Hong Kong stayed about the same size, at about 9,440 hectares: new forest grew on about 123 hectares, and about 115 hectares were lost.
What is the tree count in Hong Kong?
Hong Kong has an estimated 108,897 trees across the 8.56 km² of land measured — 50.9% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Hong Kong need?
Hong Kong has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Hong Kong's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Wan Chai, via OpenAQ; the 7-day trend is the Open-Meteo / CAMS model's estimate. Tree cover is measured from Sentinel-2 L2A (ESA Copernicus) via Earth Search satellite imagery at 10 m detail across a 2 km radius around Wan Chai; the tree count is an estimate derived from that cover.
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