Air Quality in Phnom Penh

About this tool

The card at the top of this page is the latest reading from one monitoring location: the single point that the azwebdata service holds under the city name "Phnom Penh", anchored at about 11.56°N, 104.93°E in the built-up core near the river. It is a station reading, not an average of the capital — the air on a busy boulevard, on a rooftop, or in an outer district can differ from it in either direction. Phnom Penh's pollution is urban before it is agricultural: measured rice-straw burning here is the smallest of the five provinces this site covers, while traffic, construction dust and backup generators run all year. A 2026 study that sampled at the Institute of Technology of Cambodia found carbonaceous particles in the city about three times higher in the dry-season month than in the wet-season month, with traffic-linked emissions staying steady across both — and a February pollution episode linked to smoke transported from burning areas near the Cambodia–Vietnam border. Use the card for daily decisions — the school run, a moto commute, whether to jog by the river or in a gym — and treat it as one point in a city of many.

How it works

When you open the page, your browser calls the InKhmer API's province endpoint with the id phnom-penh. The service looks up its Cambodia station table, finds the entry whose cityId is phnom-penh (latitude 11.5564, longitude 104.9282), and asks azwebdata for the latest air-quality snapshot stored under the location name "Phnom Penh". Azwebdata returns the freshest stored value for that location: scheduled Cambodian locations are refreshed every thirty minutes, and anything else is fetched on demand and held in a fifteen-minute cache. When OpenAQ has no matching station, OpenWeatherMap's modelled air-pollution values are used instead, mapped onto the same AQI bands. The number on the card is derived from the PM2.5 concentration through the US EPA breakpoint table, with PM10 as fallback — which is why almost every reading on this page is a PM2.5 story. Because the source is one monitoring point, a traffic-jam hour near that point can push the card up while a breeze on your own street changes nothing on it. If the provider stops answering, azwebdata serves the last good cached value; with nothing at all, the page shows "No air quality data at the moment" instead of inventing a number.

Use cases

• A parent in Tuol Kork checking the AQI band before the moto school run, deciding whether the children wear masks on the way.
• A delivery rider working the riverside corridors using the card to judge whether a dust-and-exhaust day means a mask and slower pace.
• An office worker deciding when the day turns hazy whether to switch the car air conditioning to recirculate for the drive home.
• An asthmatic runner comparing the morning card with the riverside jog route before choosing the gym instead.
• A construction-site supervisor checking whether the card suggests a day when dust suppression matters more than usual.
• A family planning a Sunday walk at the riverside using the band guidance to pick an hour with lower traffic.

Frequently asked questions

• Is this the official government air-quality reading for Phnom Penh?

  No. Cambodia’s Ministry of Environment runs its own monitoring programme and publishes readings through its own channels. This page is independent: it serves OpenAQ monitoring data — with OpenWeatherMap as fallback — collected through the azwebdata service, for one location in the city. Use it as a convenient public reading, not a government bulletin; for official announcements, refer to the Ministry of Environment.

• Why does the card differ from the air I breathe on my street?

  Because it is one station, not a city average. The reading comes from the single monitoring location azwebdata holds under "Phnom Penh", anchored near the river in the built-up core. A street a kilometre away can read quite differently: traffic canyons trap exhaust, open intersections and construction sites raise dust, and rooftops and parks sit above the worst of it. Use the card as the city’s reference point, and expect your own street to vary around it.

• Is the air worse at rush hour?

  The monitoring evidence points to steady local traffic sources across the year rather than a dramatic rush-hour spike at this station: a 2026 study at the Institute of Technology of Cambodia found traffic-linked carbon emissions almost unchanged between the wet-season and dry-season sampling, while the total ultrafine-particle mass was roughly three times higher in February than in September. Short-term readings can still jump with a traffic jam or a nearby construction site — the card only shows the latest value, not the day’s curve.

• Does burning season affect Phnom Penh?

  Yes, and not only from local fires. The same 2026 study traced its February pollution episode to smoke transported from biomass-burning areas near the Cambodia–Vietnam border, arriving over the city in short-range plumes. Local burning matters less in Phnom Penh than in the rice belt — measured rice-straw burning here is the smallest of the five provinces this site covers — but during the dry season, smoke from surrounding provinces and across the border can push the card up even when the city itself is quiet.

• How fresh is the reading on this page?

  Azwebdata refreshes its scheduled Cambodian snapshots every thirty minutes and serves other locations through a fifteen-minute on-demand cache, so the freshest value is normally under half an hour old. Your browser asks for the latest value when the page loads, and the card shows the time the monitor actually observed the reading. It is a snapshot, not a minute-by-minute feed and not a forecast.

• What does the page show when the station is offline?

  It degrades quietly. If the provider stops answering, azwebdata serves the last good cached value for the location, and the "Updated" line shows when that data was served. If nothing is available at all, the page shows "No air quality data at the moment" rather than an error or a made-up number.

• Which pollutant drives the AQI for Phnom Penh?

  PM2.5 — fine particles small enough to reach deep into the lungs — in almost every reading. The upstream publishes raw concentrations per pollutant, and this service derives the headline AQI from the PM2.5 value using the US EPA breakpoints, falling back to PM10 when no PM2.5 sensor reported. The pollutant table on the card still lists PM2.5, PM10, ozone, NO₂, SO₂ and CO individually.

• I live in an outer district like Chbar Ampov or near the airport — how close is the card to my air?

  Closer than any other single number you will find, but still approximate. The monitoring point behind this card sits in the built-up core near the river, while outer districts and the airport fringe have their own mixes of traffic, market smoke and open ground. When the card is Good, treat your district as probably fine; when it is Unhealthy, expect your district to be in the same broad band rather than the identical number. For block-level certainty, no one-point public feed can deliver it.

Data and accuracy

Content last reviewed 19 October 2026