Air quality

Air quality in Hạ Long today

Updated

Unhealthy for Sensitive Groups (US AQI 125) People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. Model estimate for Mon, Oct 26, 1:00 am (18:00 UTC).

Live AQI, PM2.5, PM10 and ozone for Hạ Long, Quảng Ninh, Vietnam, with a 48-hour forecast and the best time to be outside.

US AQI now
125 Unhealthy for Sensitive Groups
PM2.5
20 µg/m³ 1.4× WHO 24-h guideline
PM10
25 µg/m³
Ozone
141 µg/m³
Dominant pollutant
ozone sub-index 125
Best hour today
7:00 am AQI 101
European AQI
71

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Air quality in Hạ Long right now

Right now the modelled US Air Quality Index for Hạ Long, Quảng Ninh, Vietnam is 125, which falls in the "Unhealthy for Sensitive Groups" band (up to 150). People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors.

The index is driven mainly by ozone, whose own sub-index is 125. Ozone usually peaks in the afternoon on sunny days and falls back after sunset.

PM2.5 is 20 µg/m³, 1.4 times the WHO 24-hour guideline of 15 µg/m³; PM10 is 25 µg/m³ against a guideline of 45; ozone is 141 µg/m³ (above the WHO 8-hour level of 100); nitrogen dioxide is 3.6 µg/m³ (below the 24-hour guideline of 25).

Also this hour: carbon monoxide 342 µg/m³.

NASA FIRMS shows 185 fire hotspots within 300 km in the last day (nearest about 9 km), but particle levels are not elevated enough to point to smoke right now.

Hạ Long AQI forecast: next 48 hours

Over the next 24 hours the AQI is forecast to range from 101 around Mon 7:00 am to 161 around Mon 9:00 pm, from "Unhealthy for Sensitive Groups" at best to "Unhealthy" at worst.

The following day looks similar, averaging about 131.

Local time (Asia/Bangkok)US AQICategoryPM2.5 µg/m³PM10 µg/m³Ozone µg/m³
Mon 1:00 am125Unhealthy for Sensitive Groups20.425141
Mon 4:00 am109Unhealthy for Sensitive Groups15.319134
Mon 7:00 am101Unhealthy for Sensitive Groups19.724139
Mon 10:00 am104Unhealthy for Sensitive Groups24.428158
Mon 1:00 pm120Unhealthy for Sensitive Groups2729167
Mon 4:00 pm143Unhealthy for Sensitive Groups28.230181
Mon 7:00 pm158Unhealthy25.127174
Mon 10:00 pm161Unhealthy22.425161
Tue 1:00 am149Unhealthy for Sensitive Groups16.120138
Tue 4:00 am121Unhealthy for Sensitive Groups15.519129
Tue 7:00 am98Moderate1821134
Tue 10:00 am98Moderate19.822169
Tue 1:00 pm126Unhealthy for Sensitive Groups21.123181
Tue 4:00 pm155Unhealthy1820175
Tue 7:00 pm162Unhealthy16.718160
Tue 10:00 pm150Unhealthy for Sensitive Groups18.820145
Wed 1:00 am129Unhealthy for Sensitive Groups21.425146

Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.

Best time to be outside in Hạ Long today

Between 6 am and 9 pm local time, the cleanest air today is forecast around 7:00 am (AQI 101, Unhealthy for Sensitive Groups) and the worst around 9:00 pm (AQI 161). That is a swing of 60 points, so a run or walk around 7:00 am is noticeably better.

Hạ Long vs the rest of Vietnam

Across 68 Vietnam cities we track, the average US AQI right now is 82 (Moderate). Hạ Long at 125 is 43 points worse than average.

It ranks 68 of 68 from cleanest to most polluted; the cleanest is Phu Quoc (38) and the most polluted Hạ Long (125).

For context, the median across 3,909 cities worldwide is 57.

Air quality in cities near Hạ Long

CityDistanceUS AQICategoryPM2.5 µg/m³
Haiphong42 km92Moderate32.9
Kiến An49 km92Moderate32.9
Bắc Giang98 km106Unhealthy for Sensitive Groups60.3
Mỹ Hào103 km106Unhealthy for Sensitive Groups60.3
Việt Yên104 km106Unhealthy for Sensitive Groups60.3
Thuận Thanh104 km106Unhealthy for Sensitive Groups60.3
Bắc Ninh107 km106Unhealthy for Sensitive Groups60.3
Nam Định109 km93Moderate71.9

Model vs measured

We found no measured PM2.5 sensor cell within 25 km of Hạ Long, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.

Advice for sensitive groups

At 125, children, older adults, pregnant people and anyone with asthma, COPD or heart disease should limit time outdoors, especially strenuous activity. A well-fitted N95/FFP2 mask cuts particle exposure; it does not filter ozone.

What the US AQI numbers mean

US AQICategoryWhat it means
0-50GoodAir quality is satisfactory and poses little or no risk; a good time for outdoor activity.
51-100ModerateAcceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
101-150Unhealthy for Sensitive GroupsPeople with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors.
151-200UnhealthyEveryone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed.
201-300Very UnhealthyHealth alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors.
301-500HazardousEmergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500.

Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.

Nearby cities

More for Hạ Long

Air quality elsewhere

Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.