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Weekly Air Quality in Selected Towns of Sri Lanka (6 – 12 Jan 2025)
From the 6th – 12th January 2025, air quality was Unhealthy for Sensitive Groups (AQI 101-150) in Colombo, Battaramulla (Pelawatte & CEA) and Jaffna; Moderate (AQI 51-100) in Kurunegala, Puttalam and Ambalantota; Good in Akurana and Nuwara Eliya.
Air pollution in North India remained severe this week. From January 8th, northeasterly winds carried polluted air from Kolkata, India to Sri Lanka. This caused a rise in air pollution levels in Sri Lanka, particularly from 8th to 11th January. Air is less polluted on the western sides of the hills in places such as Nuwara Eliya, Akurana and Ambalantota. Rainfall scrubs some of the air pollution. Due to the seasonal wind patterns, air pollution stayed high throughout the week.
Battaramulla recorded the highest weekly average AQI of 145. Nuwara Eliya recorded the lowest weekly AQI of 21.
Observed fine particulate measurements by the minute for last week
The AQ variation at a fine temporal scale is shown in Colombo and Pelawatte for last three days. The peak value in Colombo was about 150 and Pelawatte was about 160.
Air Quality impact on human health
Fine particulate matter (PM 2.5) are generally 2.5 microns and smaller in size. Such particles are inhalable and easily lodges inside the lungs reducing capacity. PM2.5 is a concern for people’s health when levels in the air are high. The levels of risk are shown in the dial shown against the US EPA air quality standards. AQ has a scale that run from 0-500, that tells you how clean or polluted your air is. Each level on the scale corresponds to a different level of health concern.
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
