Analysis of 469 days of PM2.5 sensor data from the Kerobokan/Canggu area of Bali (November 2024 – March 2026) shows air quality that regularly exceeds World Health Organization guidelines. The typical daily median PM2.5 was 21.9 µg/m³ — 1.5 times the WHO annual guideline of 15 µg/m³. The data also shows periodic pollution spikes consistent with burning events.
The data comes from a single community sensor location, so these readings may not be representative of all of Bali. However, live readings from other sources (verified April 13, 2026) show similar Moderate-level air quality across the Denpasar–Ubud–Seminyak corridor, while coastal stations like Jimbaran show clean air. This suggests the issue may vary significantly by location.
The core problem is that we don't have enough monitoring to know. Bali — home to 4.4 million people and one of the world's most visited islands — has just one active government air quality sensor for the entire island. The main Denpasar government station has been offline for over 8 months. On April 1, 2026, a waste regulation change raised concerns about increased burning, but there is insufficient monitoring to measure the impact.
Live readings from multiple independent sources across Bali. Data is refreshed automatically every 2 hours from PurpleAir, AQICN, and IQAir APIs.
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The Klungkung sensor — located in East Bali, away from the main waste-affected areas — shows a consistent pattern of moderate baseline pollution with daily spikes reaching the "Unhealthy for Sensitive Groups" range. This pattern is similar to what the historical Kerobokan sensor recorded.
| Date | Daily Avg PM2.5 | Daily Max | Daily Min | EPA Category |
|---|---|---|---|---|
| Apr 7 | 22.3 µg/m³ | 64.8 | 5.0 | Moderate |
| Apr 8 | 30.1 µg/m³ | 87.1 | 10.1 | Moderate |
| Apr 9 | 33.1 µg/m³ | 84.7 | 7.6 | Moderate |
| Apr 10 | 19.7 µg/m³ | 53.2 | 11.6 | Moderate |
| Apr 11 | 25.1 µg/m³ | 51.9 | 13.4 | Moderate |
| Apr 12 | 27.8 µg/m³ | 93.5 | 7.3 | Moderate |
| Apr 13 | 21.9 µg/m³ | 56.8 | 8.1 | Moderate |
Note: Daily max spikes of 50–93 µg/m³ enter the "Unhealthy for Sensitive Groups" range and suggest intermittent pollution events even in areas away from the Denpasar waste corridor. Without more sensors, it is not possible to determine how widespread these events are.
The chart below shows every day of recorded data from the Kerobokan sensor. The blue line shows the daily median; the red line shows the daily maximum spike. Hover for exact values. Background colour bands show US EPA air quality categories.
On April 1, 2026, Denpasar authorities banned organic waste from the Suwung landfill — Bali's largest waste processing site — as part of a plan to close it by August 2026. The regulation's stated goal is a legitimate environmental objective: pushing households toward waste separation and reducing landfill dependency.
However, reports indicate that implementation has outpaced infrastructure. Without adequate composting facilities or collection alternatives in place, some residents have reportedly turned to burning waste or dumping it in waterways. Denpasar cleanup crews were reportedly removing approximately 7 tons of waste from rivers daily, according to the city's Public Works office (PUPR).
Waste burning — especially of mixed waste containing plastics — releases fine particulate matter, dioxins, furans, and other harmful compounds. The concern is not the regulation's intent, but whether adequate monitoring and infrastructure exist to manage the transition safely.
An audit of all publicly accessible air quality platforms (conducted April 13, 2026) reveals significant monitoring gaps:
| Source | Bali Stations | Type | Status |
|---|---|---|---|
| KLHK (Gov) | 1 listed (Badung Sempidi) | Government | Active — O3 only listed |
| Nafas | 4 (Ubud, Denpasar, Sanur, Pemogan) | Private (DBS Indonesia) | Active |
| IQAir | ~10 private contributors | Private citizens/businesses | Active |
| PurpleAir | 2 (Jimbaran, Klungkung) | Community sensors | Active |
| AQICN/GAIA | 1 active (Sempidi) | Government + community | Kerobokan: Offline Mar 15 Denpasar: Offline Aug 2025 |
| Sensor.Community | 0 | Open source community | No coverage |
The Denpasar government station (KLHK, located at Graha Sewaka Dharma, Lumintang) went offline on August 9, 2025. It is listed on the KLHK portal as "Sedang dalam perawatan" (under maintenance). However, a search of the KLHK station list at ispu.menlhk.go.id returns no results for "Denpasar," "Bali," or "Gianyar" — only Kabupaten Badung is listed.
The Kerobokan community sensor (GAIA network) stopped recording on March 15, 2026. As a privately owned community device, it may have simply failed or been taken offline by its operator. The reason for the outage is unknown.
The systemic issue is that Bali does not have adequate air quality monitoring infrastructure for an island of its size and importance.
| Comparison | Government AQ Stations | Population | Stations per million |
|---|---|---|---|
| Bali (current) | 1 | 4.4 million | 0.2 |
| Singapore | 18 | 5.9 million | 3.1 |
| Bangkok (Thailand) | ~70 | 10.7 million | 6.5 |
| London (UK) | 100+ | 9.0 million | 11+ |
PM2.5 refers to fine particulate matter smaller than 2.5 micrometers — small enough to penetrate deep into the lungs and enter the bloodstream. Long-term exposure is linked to respiratory and cardiovascular disease. When waste containing plastics is burned, the smoke contains additional toxic compounds (dioxins, furans) that standard PM sensors do not measure.
| Standard | PM2.5 Level | Classification |
|---|---|---|
| WHO Annual Guideline | 15 µg/m³ | Long-term target |
| WHO 24-hour Guideline | 25 µg/m³ | Safe daily limit |
| US EPA "Good" | 0–12 µg/m³ | Satisfactory |
| US EPA "Moderate" | 12.1–35.4 µg/m³ | Acceptable; concern for sensitive groups |
| US EPA "Unhealthy Sensitive" | 35.5–55.4 µg/m³ | At-risk groups affected |
| US EPA "Unhealthy" | 55.5–150.4 µg/m³ | Everyone may be affected |
| US EPA "Very Unhealthy" | 150.5–250.4 µg/m³ | Health alert |
| US EPA "Hazardous" | 250.5+ µg/m³ | Emergency conditions |
Historical air quality data for Bali is limited. Two sensors have historical CSV data publicly available from the AQICN network: Kerobokan (469 days, November 2024 – March 2026) and Denpasar government station (548 days, September 2023 – August 2025). Both are currently offline. The active Badung Sempidi station does not provide downloadable historical data through AQICN.
The Denpasar KLHK station recorded 548 days of data from September 2023 to August 2025. The average daily median was 15.1 µg/m³ — right at the WHO annual guideline of 15 µg/m³. Approximately 40% of days exceeded the WHO annual guideline, and 8% exceeded the WHO 24-hour guideline of 25 µg/m³.
Notably, the station's final two recordings showed a sharp spike — daily medians of 45.7 and 75.0 µg/m³ on August 8–9, 2025 — before going offline. The station has been offline for 8+ months with no public repair timeline.
Note: This data comes from a government-operated station in central Denpasar, representing urban conditions.
The Kerobokan sensor recorded 469 days of data from November 2024 to March 2026. The average daily median was 21.9 µg/m³ — 1.5 times the WHO annual guideline. 44% of days exceeded the WHO 24-hour guideline of 25 µg/m³. Monthly averages ranged from 7.1 to 32.7 µg/m³ depending on the month.
Located in a residential area near Canggu, this sensor may be closer to burning sources than the central Denpasar station. During the 166-day overlap period with the Denpasar station, Kerobokan readings were consistently 1.1–1.7 times higher — suggesting localised variation in air quality even within south Bali.
A monthly pattern showed higher readings from February through October and lower readings from November through March, but this cannot be confirmed as seasonal without more data points from additional years and locations.
The two historical sensors — both now offline — covered a limited area of south Bali. There is no historical data available for Ubud, Sanur, North Bali, or East Bali. The Klungkung PurpleAir sensor in East Bali currently shows similar moderate patterns but has limited history.
Without distributed monitoring, it is impossible to determine whether the patterns seen in Kerobokan and Denpasar are representative of Bali as a whole. More sensors, in more locations, recording over longer periods are needed to build a meaningful picture of the island's air quality.
All data in this document comes from publicly accessible sources. We encourage independent verification: