Air quality in Shah Alam

How bad is the air quality in Shah Alam?

Shah Alam is a city located in Malaysia, being the state capital of Selangor and found within the Petaling district. It has the distinction of being one of the first planned cities to be constructed after independence from Britain in 1957. The city was once famous for its natural resources such as rubber and palm oil, with the exports of such materials leading to further development and urbanization within more recent times. Manufacturing of goods also plays a large role in the economic security of the city, and with these activities coupled with Shah Alam’s population of more than 740 thousand inhabitants, there are bound to be pollution related issues occurring.

In 2019, Shah Alam came in with a PM2.5 reading of 20.4 μg/m³, placing it into the ‘moderate’ ratings bracket, a grouping that requires a PM2.5 reading of anywhere between 12.1 to 35.4 μg/m³ to be classified as such.

PM2.5 refers to particulate matter that is 2.5 micrometers or less in diameter, making it approximately 3% the width of a human hair, sometimes going even smaller down to sizes such as 0.001 microns. Due to its incredibly small size, it has a whole host of negative health effects when respired, and as such is used as a major component in the calculation of the overall air quality, or air quality index (AQI).

Shah Alam’s reading of 20.4 μg/m³ placed it in 866^th place out of all cities ranked worldwide, as well as 4^th place out of all cities ranked in Malaysia. This shows that Shah Alam does indeed have issues with its pollution levels, with certain months being of more danger than others, which will be discussed in short.

What are the main causes of pollution in Shah Alam?

As a city that has undergone rapid urbanization, and still continues to do so till this day in a similar manner to many other cities in Malaysia, subsequently there would be large amounts of pollution related to this growth, as well as the influx of people and their day to day movements.

With its close proximity to the capital city of Kuala lumpur, Shah Alam helps to absorb a large amount of people that would otherwise continue to cause the population to rise in the capital. Commutes between the cities would be common place, and due to this movement large amounts of personal vehicles would be used. On a modern cultural level, Malaysians are attached to their vehicles and despite the government pouring a huge amount of investment into public transport, the number of personal vehicle owners continues to rise, with heavy fuel subsidies further compounding this issue.

As such, fumes from vehicles would be a major source of pollution, with massive amounts of cars and motorbikes inhabiting the road, alongside heavy duty vehicles such as lorries, trucks and buses, many of which have outdated engines running on lower quality or diesel fuels, putting out far larger quantities of pollution than cleaner counterparts would.

Other sources of pollution would be from factory emissions, and smoke and fumes arising from similar industrial areas. Construction sites can also contribute heavily to pollution levels, giving off large amount of fine particulate matter and in some cases dangerous metals such as mercury or lead. Open burn sources would be a minor issue, but of note is that vehicular pollution coupled with industrial fumes would be the main causes of pollution in Shah Alam.

When is the air quality at its worst in Shah Alam?

Observing the data taken over 2019, the months that came in with the highest levels of pollution followed a very similar trend to the rest of Malaysia, due to the ever pertinent issue of forest and farmland fires in Indonesia taking place. The huge plumes of smoke can be blown over the sea and afflict not only Shah Alam but also Singapore and southern Thailand, as well as the rest of the Malaysian peninsula.

These fires take place during September, and as such the corresponding pollution levels often match that time. The months of May through to July remain fairly decent in their numbers (although still elevated enough to cause health issues), before they rise suddenly in August to 23.3 μg/m³ and then a jump in PM2.5 that is nearly double that of the previous month, with a reading of 45.5 μg/m³ in September.

This places it into the ‘unhealthy for sensitive groups’ bracket, a rating that requires 35.5 to 55.4 μg/m³ to be classed as such. It is the only month of the year to reach up into this grouping, and as such would present a large amount of negative health impacts on vulnerable demographics of the population.

When is the air at its cleanest in Shah Alam?

In contrast to the previous question, the months that had the best readings of air quality in Shah Alam seemed to be lacking any distinct pattern, save for the jump in PM2.5 during September. However, when these high pollution levels at the end of the year abated, the numbers were seen to drop somewhat down to more reasonable numbers (although unfortunately never breaking out of the ‘moderate’ ratings bracket).

The months that came in with the best air quality readings were at the very end of the year, November and December, as well as June coming in with a similar rating of relatively cleaner air. In order of months, the readings were 15.8 μg/m³ for June, 15.8 μg/m³ for November and 15.7 μg/m³ for December. This displays that December was the cleanest month of the year in Shah Alam, but only by a very fine margin.

What are some of the main pollutants found in the air in Shah Alam?

With a large amount of its pollution coming from sources such as vehicle emissions, as well as the use of fossil fuels such as diesel as well as coal, subsequently the air would be full of related pollutants. These would include ones such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂), with nitrogen dioxide often being found in high quantities over areas that see higher volumes of traffic.

Others would include particulate matter such as black carbon and silica dust, released from the combustion of fossil fuels, biomass as well as silica finding its source in construction sites. Both are known carcinogens, which would drive up rates of lung and throat cancer as well as causing damage to the environment and climate.

A few other chemicals permeating the air would be ozone (O₃), carbon monoxide (CO₂), polynuclear aromatic hydrocarbons, and volatile organic compounds (VOC's) such as benzene, xylene, toluene, methylene chloride and formaldehyde.

These are but a few of the pollutants that would be found in the air in Shah Alam, with many more being present, with quantities varying from area to area and all with a plethora of harmful effects on human health.