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Weekly Air Quality in Selected Towns of Sri Lanka (18-24 Nov 2024)
Last week Moderately poor air quality (AQI 51–100) was recorded in Jaffna, Battaramulla(CEA), Digana, Negombo, Gampaha, and Colombo (US Embassy) while Ambalantota, Akurana, Nuwara Eliya, Kurunegala, Trincomalee, and Puttalam had good air quality (AQI 0–50), with the cleanest air in these areas. Air quality in Jaffna was unhealthy (AQI 151-200) on the 22nd of November, recorded at 153.
Last week, winds from the Northern Indian Ocean carried air across the Bay of Bengal at speeds of 25 to 45 km/h, at an elevation of 1.2 km. In the coming week, there is a cyclonic storm traversing 100-300 km east of Sri Lanka from the 24-26th. This shall probably dilute poor quality air coming in from the Northern polluted sub-continent and also scrub any pollution.
Jaffna recorded the highest weekly average AQI of 80. Ambalantota recorded the lowest weekly AQI of 29.
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 155.
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
