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Weekly Air Quality in Selected Towns of Sri Lanka (4-10 Nov 2024)
On the 6th and 7th of November, Battaramulla, Gampaha, and Puttalam experienced alarming levels of air pollution (AQI 151 – 200). Such high values are rare in Sri Lanka. Air quality in Dambulla, Digana, and Negombo was unhealthy for sensitive groups (AQI 101 – 150) . Moderately poor AQ was recorded in Battaramulla (CEA), Trincomalee, and Kurunegala (AQI 51 – 100) . Good air quality (AQI 0 – 50) was observed in Akurana and Nuwara Eliya, indicating the cleanest air conditions in these areas.
Last week, there was historical bad air pollution in Pakistan and Northern Indian. The winds carried polluted air masses from the Northern Indian Ocean across the Bay of Bengal and Arabian seas. Because of the wind directions, AQI peaked and was especially severe on November 6th and 7th, resulting in some of the worst air quality conditions observed in Sri Lanka.
Battaramulla recorded the highest weekly average AQI of 91. Akurana recorded the lowest weekly AQI of 43.
Observed fine particulate measurements by the minute for last week
The AQ variation at a fine temporal scale is shown in Pelawatte and Colombo for last three days. The peak value in Pelawatte was about 160 and Colombo was about 150.
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