Qualité de l’air à Alor Setar

Is Alor Setar a city with polluted air?

Alor Setar, formerly known as Alor Star for a period of time between 2004 to 2008, is a city located in in Malay state of Kedah, being the capital city of said state as well as the second largest city statewide. With a population of over 405 thousand (taken in 2010, hence a number that will have risen considerably since), as well as having a status as a major transportation hub for those moving between Thailand and Malaysia due to its location, Alor Setar is subject to some fairly prominent levels of pollution due to the mass movement of people through the city, as well as the general activity of its inhabitants.

Whilst it does not suffer from the same terrible spikes in pollution levels towards the end of the year due to its northernmost position in peninsular Malaysia (being situated further away from the Sumatran region of Indonesia where major forest fires started by farmers cause massive spikes in pollution in the more southwestern cities and states), there are still many months that have less than appreciable air quality levels, for a number of reasons which will be discussed in short.

In 2019, Alor Setar came in with a PM2.5 reading of 12.7 μg/m³ as its yearly average, placing it by a fine margin into the ‘moderate’ pollution bracket, which requires a PM2.5 reading of anywhere between 12.1 to 35.4 μg/m³ to be classified as such. This reading also placed it in 1596^th place out of all cities ranked worldwide, as well as 45^th place out of all cities ranked in Malaysia, showing that it could take some action to improve its air quality levels further, and at the same time being fortunate that it has strong coastal winds to blow away accumulations of pollution as well as not being subject to excessive amounts of the Indonesian haze clouds.

What are the causes of polluted air in Alor Setar?

Like many of the cities and states throughout Malaysia, Alor Setar sees similar causes of pollution occurring that lead to the many spikes in PM2.5 witnessed throughout the course of the year, with a majority of the causes being local ones, and the end of year issue finding its origin in another country. Some of the local ones include the mass over reliance on vehicles, with countless cars and motorbikes inhabiting the roads, giving out large amounts of chemical pollutants as well as fine particulate matter.

Other significant causes include emissions from factories, industrial zones and power plants, with a majority of their energy coming from coal, which along with diesel fuels found in cars (and in particular heavy duty vehicles such as lorries and trucks) contribute heavily to the pollution level in Alor Setar. In closing, the forest fires that happen in Indonesia towards years end are also a major contributor to poorer air quality, with this period often causing dangerous spikes in pollution when the fires occur, and although this period is short lived, it is still prominent enough to cause damage to people who are exposed to the smoke and haze clouds.

When is pollution at its highest in Alor Setar?

In following from the previous question, the time period in which Alor Setar was at its most polluted was not as clearly defined as many cities around the world, mostly due to the climate of the city, which differs little in temperature throughout the year, only having a rainy season and dry season (which still has a large amount of rain occurring anyhow). In cities that see colder winter months, there is usually a correlated period of higher pollution, with colder temperatures often coinciding with subsequent anthropogenic activities that lead to more pollution being produced (such as increased electricity usage for heating, as well as the burning of firewood and other similar materials).

In Alor Setar, the months that saw the highest levels of pollution were March and April in the beginning of the year, and then June through to September (with the month of May having a sudden dip down to 9.1 μg/m³ and then jumping back up to 12.4 μg/m³ the following month). September was the most polluted month of the entire year with its reading of 21.5 μg/m³, due to the already polluted air being compounded by the aforementioned trans-border smoke clouds.

Who is most at risk to pollution in Alor Setar?

Whilst all members of the population are at risk from elevations in the air pollution level, there are certain demographics who would be more at risk, for a varying amount of reasons. These would include among them young children, who are susceptible to developing allergies that can turn into life long problems, as well as stunting of physical or mental development due to over exposure.

Others include the elderly, those with compromised immune systems as well as preexisting health conditions, and pregnant mothers. The last group are particularly at risk during this vital period of time whilst they are carrying their unborn child, with excessive exposure to pollution leading to serious cases such as miscarriage, babies being born with a low birth weight or prematurely, as well as with physical or cognitive defects (similar to that of young children who are exposed).

What are some of the main types of pollutants found in Alor Setar?

Some of the more prominent types of pollution found in Alor Setar would be ones that typically find their source from combustion sites, such as in vehicle engines or factories, as well as the forest fires that occur. They would include chemical compounds such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂), both of which are released in high quantities from vehicles, and are the leading contributors towards incidences of acid rain, as well as both having the ability to cause irritation and damage to the lining of the lungs. Other pollutants would be ones such as black carbon and volatile organic compounds (VOC's), both of which find their origin in the incomplete combustion of fossil fuels as well as organic material. Some examples of VOC's include benzene, toluene, xylene, methylene chloride, tetrachloroethylene and formaldehyde. These are a number of some of the main pollutants found in the air in Alor Setar.