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Weekly Air Quality in Selected Towns of Sri Lanka ( 14 – 20 September 2026)
Summary for 14 – 20 September 2026:
From 14–20 September, air quality across Sri Lanka was generally in the ‘Good’ to ‘Moderate’ range. Air masses entered Sri Lanka mainly from the southwestern direction.
Weekly Air Quality Ranking:
The monitored locations with the highest weekly average AQI values were:
- Battaramulla – 65
- Akurana – 64
- Digana – 61
- Chilaw – 61
- Anuradhapura – 61
Chilaw recorded the highest daily average AQI of 89 during the week, which falls within the ‘Moderate’ category.
Based on the weekly average AQI, Akurana, Digana, Mirihana, Battaramulla, Puttalam, Chilaw, Jaffna and Anuradhapura were in the ‘Moderate’ category, while Nuwara Eliya, Colombo, Kurunegala, Negombo, Kalawana, Ambalantota, Mannar, and Trincomalee were in the ‘Good’ category.
Weekly Air Quality Index (AQI) Levels:
- Moderate (AQI 51-100): Akurana, Digana, Mirihana, Battaramulla, Puttalam, Chilaw, Jaffna, Anuradhapura
- Good (AQI 0-50): Nuwara Eliya, Colombo, Kurunegala, Negombo, Kalawana, Ambalantota, Mannar, Trincomalee
Observed fine particulate measurements by the hour for the last week
AIR QUALITY BASICS
Air pollution, a widely- talked and argued topic today has been a primary cause of unforeseen climatic changes, many health problems associated with respiratory diseases and ecosystem damage. Vehicular and industrial emissions, dust, burning of fossil fuels, open burning of garbage waste and natural phenomena such as volcanoes, wildfires and pollen contribute to air pollution. Polluted air consists of both particulate matter of fine dimensions and gaseous matter. The presence of these impurities decreases the pureness of the air we breathe.
AQI
United States Environmental Protection Agency (US EPA) has set up a standard to measure the level of air pollution by the following 5 major air pollutants:
- Ground- level ozone (O3)
- Particle pollution (PM2.5 and PM10)
- Carbon monoxide (CO)
- Sulphur dioxide (SO2)
- Nitrogen dioxide (NO2)
Particulate matter of diameter less than 2.5 micrometers (PM2.5) and diameter less than 10 micrometers (PM10) and gases, ozone, carbon monoxide, sulphur dioxide and nitrogen dioxide have been identified as major air pollutants.
The AQI standard for ozone and particle pollution according to US EPA comprises of six categories. Each category is assigned a specific colour and corresponds to a different level of health concern. As the scale grows the air quality turns from good to extremely unhealthy.
Access to real- time air quality data from laser air quality sensoring instruments operated by FECT is available at www.cleanair.lk
