Air quality
Air quality in Semarang today
Updated
Moderate (US AQI 90) Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. Model estimate for Mon, Oct 26, 9:00 am (02:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Semarang, Central Java, Indonesia, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 90 Moderate
- PM2.5
- 31 µg/m³ 2.1× WHO 24-h guideline
- PM10
- 35 µg/m³
- Ozone
- 67 µg/m³
- Dominant pollutant
- PM2.5 sub-index 90
- Best hour today
- 9:00 am AQI 90
- European AQI
- 49
Air quality in Semarang right now
Right now the modelled US Air Quality Index for Semarang, Central Java, Indonesia is 90, which falls in the "Moderate" band (up to 100). Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
The index is driven mainly by PM2.5, whose own sub-index is 90. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 31 µg/m³, 2.1 times the WHO 24-hour guideline of 15 µg/m³; PM10 is 35 µg/m³ against a guideline of 45; ozone is 67 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 15 µg/m³ (below the 24-hour guideline of 25).
Also this hour: UV index 4.8, carbon monoxide 770 µg/m³.
Semarang AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 90 around Mon 9:00 am to 134 around Mon 8:00 pm, from "Moderate" at best to "Unhealthy for Sensitive Groups" at worst.
The following day is expected to be worse, averaging about 110 against 101 for the next 24 hours.
| Local time (Asia/Jakarta) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Mon 9:00 am | 90 | Moderate | 31.2 | 35 | 67 |
| Mon 12:00 pm | 92 | Moderate | 37 | 43 | 151 |
| Mon 3:00 pm | 94 | Moderate | 38.4 | 45 | 168 |
| Mon 6:00 pm | 119 | Unhealthy for Sensitive Groups | 30.9 | 36 | 144 |
| Mon 9:00 pm | 128 | Unhealthy for Sensitive Groups | 36.9 | 39 | 114 |
| Tue 12:00 am | 94 | Moderate | 38.1 | 43 | 64 |
| Tue 3:00 am | 97 | Moderate | 30.2 | 33 | 34 |
| Tue 6:00 am | 97 | Moderate | 31.4 | 35 | 21 |
| Tue 9:00 am | 98 | Moderate | 31.3 | 35 | 36 |
| Tue 12:00 pm | 98 | Moderate | 36.2 | 42 | 86 |
| Tue 3:00 pm | 98 | Moderate | 42.5 | 44 | 121 |
| Tue 6:00 pm | 101 | Unhealthy for Sensitive Groups | 50.8 | 53 | 120 |
| Tue 9:00 pm | 107 | Unhealthy for Sensitive Groups | 57.9 | 59 | 106 |
| Wed 12:00 am | 113 | Unhealthy for Sensitive Groups | 61.7 | 63 | 94 |
| Wed 3:00 am | 121 | Unhealthy for Sensitive Groups | 63.3 | 65 | 73 |
| Wed 6:00 am | 131 | Unhealthy for Sensitive Groups | 51.2 | 54 | 55 |
| Wed 9:00 am | 136 | Unhealthy for Sensitive Groups | 50.8 | 53 | 127 |
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 Semarang today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 9:00 am (AQI 90, Moderate) and the worst around 8:00 pm (AQI 134). That is a swing of 44 points, so a run or walk around 9:00 am is noticeably better.
Semarang vs the rest of Indonesia
Across 80 Indonesia cities we track, the average US AQI right now is 124 (Unhealthy for Sensitive Groups). Semarang at 90 is 34 points cleaner than average.
It ranks 27 of 80 from cleanest to most polluted; the cleanest is Banda Aceh (30) and the most polluted Palangkaraya (500).
For context, the median across 3,909 cities worldwide is 57.
Air quality in cities near Semarang
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Jepara | 52 km | 85 | Moderate | 20.4 |
| Batang | 65 km | 85 | Moderate | 20.4 |
| Surakarta | 77 km | 77 | Moderate | 17.3 |
| Grogol | 81 km | 77 | Moderate | 17.3 |
| Pekalongan | 83 km | 84 | Moderate | 26.1 |
| Kedungwuni | 85 km | 84 | Moderate | 26.1 |
| Yogyakarta | 90 km | 86 | Moderate | 13.5 |
| Tegal | 142 km | 82 | Moderate | 21.8 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Semarang, 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.
Wildfire smoke
PM2.5 is forecast to reach 40 µg/m³ in the next 24 hours while NASA satellites detected 4 fire hotspots within 300 km in the last day (nearest about 206 km away). Smoke is a likely contributor: keep windows closed, run an air purifier or HVAC filter, and check the fire map before heading out.
Advice for sensitive groups
At 90, most people are fine outdoors. If you are unusually sensitive to PM2.5, keep long or intense workouts to the cleaner hours shown above.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency 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 Semarang
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.