Qualité de l’air à Gampaha

How bad is the level of air pollution in Gampaha?

Gampaha is a city located in the western province of Sri Lanka, within Gampaha district, one of twenty five different districts found throughout the island country. Despite being a city with a relatively small size and population, being home to 62,797 inhabitants (as per a census conducted in 2014), it has come in with some high levels of air pollution, ranking high on the global circuit over the year of 2020, as well as continuing to come in with higher readings of US AQI in Mid-2021.

Of note is that in the late months of May 2021, through to early June, a major pollutive event occurred when a ship carrying large amounts of chemicals and plastic material caught fire off the coast of Colombo. Colombo is the commercial capital of Sri Lanka as well as being the largest city when going by population size.

Although Gampaha itself was not majorly affected by the event, its close proximity to Colombo and also the resulting disaster has left the whole of Sri Lanka devasted by its pollutive effects, giving out not just many tons of extremely dangerous air pollutants (some of which would be far more toxic than the average pollution caused by cars, factories and other more ‘normal’ polluting sources), but also huge quantities of plastic waste, with the nearby coastline being absolutely saturated with plastic pellets, microplastic particles, as well as many other hazardous chemical compounds and fine particulate matter causing damage to both the environment and the health of humans and marine animals.

Observing some of the US AQI numbers on record in early June of 2021, it can be seen that Gampaha came in with a US AQI reading of 57, a number that would place it into the ‘moderate’ air pollution ratings bracket, which requires a reading of anywhere between 51 to 100 to be classified as such and is color coded as yellow, as per all the air quality maps and graphs present throughout the IQAir website. Whilst this level of air pollution would not present any major issues for the general public, who may be able to go about their day with little issue, sensitive individuals may be more at risk somewhat, with mild respiratory symptoms starting to make themselves present.

US AQI itself is an aggregate of several different main pollutants found in the air, namely PM2.5 and PM10 (with the former being considered as one of the most dangerous pollutants that goes into forming the US AQI number, and is thus used as a prominent measure of pollution in its own right, as will be discussed in the following questions). Other chemicals include nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃), a secondary pollutant that is formed when the various gases, chemicals or oxides of nitrogen (NOx) are exposed to a large amount of solar radiation, which is abundant in Sri Lanka due to its tropical climate.

Whilst the aforementioned US AQI reading of 57 is not overtly bad by any means, there are many other times of the year where the pollution level goes up considerably, causing its yearly average to be skewed somewhat. This is indicative that Gampaha is a city that could still do much to improve its yearly pollution levels.

Why is Gampaha such a polluted place to live?

The main causes of polluted air in Gampaha are ones that are typically present in many cities throughout the world, only with differences present due to lack of stringent rules and regulations regarding emission standards, vehicle quality and other polluting sources or events. As was mentioned before, whilst the ship burning incident off the coast of neighboring Colombo wreaked havoc on the environment and air in 2021, Gampaha has its yearly ambient air pollution levels consistently elevated by sources such as vehicles, which remain as one of the biggest causes of problematic air pollution spikes in Gampaha, and indeed much of Sri Lanka.

Vehicle ownership has gone up massively over the past few decades, causing huge traffic jams to start to appear, which can cause the pollution level to rise to the great heights as seen on record, giving out many tons of hazardous chemical compounds and clouds of fine particles. As well as this, other major sources include the burning of firewood or charcoal in certain households, along with emissions from factories, power plants and industrial sites.

What are some harmful pollutants found in the air in Gampaha?

Besides the aforementioned main pollutants that go into making up the US AQI figure, there would be a number of other main air pollutants present in Gampaha (not to mention the huge amount of highly toxic fumes and particles released from the burning event off the coast of Colombo, which could easily be blown inland towards Gampaha).

Other harmful contaminants include ones such as black carbon and volatile organic compounds (VOCs), both of which are formed from the incomplete combustion of both fossil fuels and organic matter. Many of the heavily aged vehicles in use across the city would also leak large amounts of noxious oil vapors, as well as pollutants like lead, mercury and cadmium being found near construction sites, or as a result of burning certain materials (with waste and refuse burning also contributing to this).

When does Gampaha experience the highest levels of pollution?

Observing the data collected over 2020, it can be seen that despite having air quality data missing for the months of January and February (due to lack of high quality data or air quality monitors during that time), the month of March came in as the most highly polluted of the year, with a PM2.5 reading of 56.5 μg/m³, placing it into the ‘unhealthy’ air quality ratings bracket, which requires a PM2.5 reading of anywhere between 55.5 to 150.4 μg/m³ to be classified as such.

The rest of the year all saw ‘moderate’ air pollution readings (12.1 to 35.4 μg/m³), and whilst some months had readings on the lower end of this spectrum, the last three months of the year all came in with PM2.5 elevations, with readings of 35.3 μg/m³, 32.5 μg/m³ and 30.9 μg/m³ respectively.

Does Gampaha see any improvements in its air quality?

As mentioned, whilst no month of 2020 fell out of the ‘moderate’ pollution ratings bracket, there were several months that came in on the lower end of this rating. June through to September had the lowest levels of PM2.5, coming in with readings of 19.2 μg/m³, 19.6 μg/m³, 20.7 μg/m³ and 15.8 μg/m³.

This made September the cleanest month by a significant amount, being a time period in which the air would be significantly freer from smoke, haze and other air contaminants, only a few units away from being moved into the ‘good’ air quality ratings bracket (color coded as green, and requiring a fine margin of entry at 10 to 12 μg/m³).