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Colombo air quality drops to unhealthy levels

Smog in Colombo this morning. Photo by Nazly Ahmed. Used with permission.

Air pollution in Colombo reached a disconcerting “unhealthy” level this morning, according to the US Embassy.

As at 8.30am today, air quality in Colombo had reached 173 AQI (air quality index) points, as announced by the embassy today. By 3pm today, it had dropped to 130 AQI, which is deemed “unhealthy for sensitive groups”.

The US Embassy records air quality using an air quality monitor (AQM) installed in central Colombo, as part of a US State Department and US Environmental Protection Agency (EPA) initiative to monitor air quality at US embassies across the globe.

This morning’s unhealthy levels of pollution, according to the Embassy, meant that “everyone may begin to experience health effects” and that “members of sensitive groups may experience more serious health effects”.

As of now, sensitive groups may suffer as a result, although the general public is unlikely to be affected.

Explaining its readings, the Embassy said: “PM 2.5 is a standard recognised by the US EPA and allows us to compare against US standard measures.  PM 2.5 particulates are of concern since they are small enough to directly enter the lungs and even the bloodstream.  Particulates less than 2.5 micrometres in diameter (PM 2.5) are referred to as “fine” particulates and are believed to pose the largest health risks–those risks are likely to be more severe for sensitive populations, including people with heart or lung disease, children, and older adults.

“The US EPA has developed a formula to convert PM 2.5 readings into an air quality index (AQI) value that can be of assistance in making health-related decisions.  For example, an AQI value of 50 represents good air quality with little potential to affect public health, while an AQI value over 300 represents hazardous air quality.”

It is at present unclear why there was a sudden worsening of air quality in Colombo, though there is speculation online that it might be smog from India making its way south.

However, according to Hemantha Vithanage of the Centre for Environmental Justice, a drop in air quality this time of year is not unprecedented.

Increased levels of air pollution have been observed around the month of September for about 15 years now, he said, though no one has carried out satisfactory research to pinpoint an exact cause.

However, Vithanage told RepublicNext it could be due to emission from ships and tankers coming into the Colombo port.

“Around September every year, there are high levels of sulphur dioxide in the air. It might be due to Kelanitissa or the Colombo port, but it could also be due to seasonal changes, with polluted air blowing in the wind from elsewhere,” he said.

PM 2.5 dust is higher than ever in Colombo these days, said Vithanage, due to ongoing construction work in the city.

Fine particles emanating from the construction sites at the Colombo Port city and various buildings from Town Hall to Slave Island could be a cause for this, though that cannot explain the increase in sulphur content, which Vithanage said may be coming from elsewhere.

“It’s hard to say that it’s definitely from India. It would depend on wind direction, too. If it’s coming to Colombo, then it should affec other areas along the way, such as Jaffna and Anuradhapura,” he said.

“All ships on the shipping line to Colombo burn heavy, bunk oil with high sulphur content. Some ships burn more than others,” he added.