When is the best time to be outside in Hong Kong?

Sat 04:00–7:00. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 34. The worst hour is around Sat 21:00, at 178.

What is the main pollutant in Hong Kong?

Fine particles (PM2.5). It drives the index right now, at 12 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.

How does Hong Kong's air compare with the WHO guideline?

2.0 times the guideline. Over the next 24 hours PM2.5 averages about 31 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. NO2 is also forecast above its guideline level.

How many cigarettes is a day of Hong Kong's air?

About 1.4 cigarettes. Over the next 24 hours PM2.5 averages about 31 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.

Will air quality in Hong Kong improve this week?

Tuesday looks cleanest. Its AQI peaks at 94, against 178 on Saturday, the worst day in the forecast.

Hong Kong air quality

Q: Is the air in Hong Kong safe today?

For most people, yes. Right now the US AQI in Hong Kong is 57, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort. It is expected to reach 178 (unhealthy) around Sat 21:00.

Hong Kong · Live AQI and hourly forecast for the next 5 days · valid Sat 01:00 local time

Moderate

US AQI, mostly PM_2.5

Model estimate. Nearby measurements are shown separately.

Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.

Next 24 hours: 32–178US AQI, highest around Sat 21:00
Best time outside: Sat 04:00–7:00US AQI about 34
PM_2.5 vs WHO guideline: 2.0×31 µg/m³ over 24 h, guideline 15
Cigarette equivalent: ≈ 1.4 a dayBerkeley Earth rule of thumb

Loading the live globe…

The live globe, centred on Hong Kong. Switch pollutants, drag through the next 5 days or press play. Full map →

Pollutants in Hong Kong right now

Pollutant	Now	Level	Next 24 h vs WHO
Fine particles PM_2.5	12 µg/m³	Moderate	2.0×
Coarse particles PM₁₀	15 µg/m³	Good	0.7×
Nitrogen dioxide NO₂	27 µg/m³	Good	2.2×
Ozone O₃	70 µg/m³	Good	0.7×
Sulphur dioxide SO₂	19 µg/m³	Good	0.7×
Carbon monoxide CO	156 µg/m³	Good	0.1×
Aerosol optical depth	0.24	Whole atmosphere · dimensionless
Desert dust	0 µg/m³	Modelled surface dust
UV index	0	Low

“Next 24 h vs WHO” compares the forecast with the World Health Organization’s 2021 guideline levels: 24-hour means of 15 µg/m³ for PM_2.5, 45 for PM₁₀, 25 for NO₂, 40 for SO₂ and 4 mg/m³ for CO, and 100 µg/m³ over 8 hours for ozone. Above 1× is above the guideline. Levels follow the US AQI, which is far less strict than the WHO, so air rated Good can still be above a guideline.

Next 48 hours

Hourly US AQI. Highest 178 around Sat 21:00, lowest 32 around Sat 04:00.

50100150

Good 0–50Moderate 51–100Sensitive 101–150Unhealthy 151–200Very unhealthy 201–300Hazardous 301+

5-day air quality forecast for Hong Kong

Daily range of the hourly US AQI, from lowest to highest, on a scale of 0 to 200.

Day	US AQI	At worst	Worst hour	PM_2.5 avg	UV max
Sat 14 Nov	32–178	Unhealthy	21:00	29	6 High
Sun 15 Nov	66–152	Unhealthy	21:00	33	6 High
Mon 16 Nov	67–95	Moderate	0:00	24	5 Moderate
Tue 17 Nov	67–94	Moderate	22:00	22	4 Moderate

Common questions about the air in Hong Kong

Is the air in Hong Kong safe today?
For most people, yes. Right now the US AQI in Hong Kong is 57, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort. It is expected to reach 178 (unhealthy) around Sat 21:00.
When is the best time to be outside in Hong Kong?
Sat 04:00–7:00. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 34. The worst hour is around Sat 21:00, at 178.
What is the main pollutant in Hong Kong?
Fine particles (PM_2.5). It drives the index right now, at 12 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.
How does Hong Kong's air compare with the WHO guideline?
2.0 times the guideline. Over the next 24 hours PM_2.5 averages about 31 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. NO₂ is also forecast above its guideline level.
How many cigarettes is a day of Hong Kong's air?
About 1.4 cigarettes. Over the next 24 hours PM_2.5 averages about 31 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.
Will air quality in Hong Kong improve this week?
Tuesday looks cleanest. Its AQI peaks at 94, against 178 on Saturday, the worst day in the forecast.

Measured near Hong Kong

Station and measurements	Distance	US AQI	Level
Mong Kok OpenAQ, reference monitor PM_2.5: 11 µg/m³ · Sat 00:00 PM₁₀: 18 µg/m³ · Sat 00:00 NO₂: 73 µg/m³ · Sat 00:00 O₃: 29 µg/m³ · Sat 00:00 SO₂: 3.0 µg/m³ · Sat 00:00 CO: 641 µg/m³ · Sat 00:00	0.4 km	55	Moderate
Sham Shui Po OpenAQ, reference monitor PM_2.5: 11 µg/m³ · Sat 00:00 PM₁₀: 16 µg/m³ · Sat 00:00 NO₂: 46 µg/m³ · Sat 00:00 O₃: 46 µg/m³ · Sat 00:00 SO₂: 4.5 µg/m³ · Sat 00:00	1.6 km	54	Moderate
Unnamed sensor OpenAQ, low-cost sensor NO₂: 69 µg/m³ · Sat 00:00 O₃: 32 µg/m³ · Sat 00:00 SO₂: 4.8 µg/m³ · Sat 00:00 CO: 427 µg/m³ · Sat 00:00	4.3 km	34	Good

Air quality near Hong Kong

US AQI right now. Cleanest nearby: Manila (36); worst: Hanoi (207). The tick on each bar is Hong Kong, at 57.

Shenzhen 27 km NW 57 Moderate
Guangzhou 129 km NW 109 Sensitive
Taipei 811 km NE 66 Moderate
Hanoi 873 km W 207 Very unhealthy
Wuhan 920 km N 168 Unhealthy
Manila 1,119 km SE 36 Good

All 162 cities →

About this forecast

Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (about 10 km inside Europe). Global runs update every 12 hours and European runs every 24 hours. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown. Nearby station measurements are independent observations, not adjustments to the forecast. The point forecast uses Open-Meteo’s CAMS products, including a separate carbon monoxide product; it can differ from the globe’s global grid. The AQI rates each hour on the US EPA scale, the same way the map colors it; official daily figures average over 24 hours (8 for ozone), so they can read lower after a short peak. Readings for 22.32°N, 114.17°E, valid 2026-11-13 17:00 UTC.