Air quality in Selangor

Air quality index (AQI) and PM2.5 air pollution in Selangor

LAST UPDATE (local time)


Real-time Selangor
Most polluted city ranking

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#cityUS AQI
1 Petaling Jaya


2 Klang


3 Kuala Selangor


4 Shah Alam


5 Banting


6 Kuala Langat


(local time)


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Real-time Selangor
Cleanest city ranking

Tooltip icon
#cityUS AQI
1 Kuala Langat


2 Banting


3 Shah Alam


4 Kuala Selangor


5 Klang


6 Petaling Jaya


(local time)

Unhealthy for sensitive groups
Very unhealthy
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How to best protect from air pollution?

Reduce your air pollution exposure in Selangor

Is Selangor a polluted state?

Selangor is one of the 13 states of peninsular Malaysia, located on the west coast, finding itself close to the capital city of Kuala Lumpur. It has the largest economy out of all states in Malaysia, as well as the largest population with a highly developed infrastructure. Whilst these factors go a long way in improving the quality of life for its citizens, they can also be contributing factors to pollution levels, as with a high population and road infrastructure often comes a large amount of vehicle usage.

Looking at the different cities located in the state, the readings taken over 2019 can have telling signs as to the levels of Selangor's overall pollution levels. The city of Klang, Selangor's most polluted city in 2019 came in with a PM2.5 reading of 20.7 μg/m³, placing it into the ‘moderate’ pollution bracket, which requires a PM2.5 reading of anywhere between 12.1 to 35.4 μg/m³ to be placed in this group.

This reading placed Klang into 845th place out of all cities ranked worldwide, not a particularly terrible rating when compared to some highly polluted cities such as Ghaziabad in India, which came in at 1st place out of all cities worldwide with a PM2.5 reading of 110.2 μg/m³.

Whilst this is somewhat of a drastic contrast, it does highlight that Klang and therefore Selangor is not suffering from overly polluted atmosphere, however not a single month out of the year of 2019 fell below the moderate rating in Klang. This remains true for the other cities in Selangor, with none of them falling below a moderate rating save for two months in the city of Kuala Selangor, which saw November and December fall into the ‘good’ ratings bracket with readings of 11.1 μg/m³ and 10.9 μg/m³ respectively.

Whilst all the cities suffered from the usual late year spike in pollution due to the forest fires from Sumatra, there was a distinct lack of cleaner months that are usually seen in peninsular Malaysia due to the heavy rain that occurs during monsoon season. As such it can be said that Selangor has an ambient pollution level that could certainly be improved upon.

What are the main causes of lower air quality in Selangor?

Due to a somewhat large statewide population of some 6.5 million inhabitants, there would also be a massive usage of automobiles, with cars and motorbikes finding themselves in large numbers on the road. This is an issue on a country wide level, with many Malaysian citizens being over reliant on their personal cars due to heavy amounts of money and development put into road infrastructure, along with large amounts of government subsidies on fuel, making commuting by car a very desirable way to get around in Malaysia.

Besides the vehicles on the road contributing to the year-round levels of PM2.5 and PM10 (with spikes of pollution seen in certain times of the day, particularly rush hour periods), there are also other pollution sources such as the factories and the industrial sector (with construction areas helping to contribute to pollution levels through fine particles escaping from poorly maintained sites).

Numerous factories can be seen in the city’s limits, with paper manufacturers, garment production lines as well as paint and plastic industries all being fairly prevalent. Many of these would rely on fossil fuels for energy, and as such the burning of coal would take place to provide their power, releasing even more pollutants into the air alongside other fumes released through the industrial process (with plastic factories releasing molten plastic fumes as well as microplastic particles into the atmosphere).

On a final and most prominent note, the forest and farmland fires that occur in Indonesia, in particular the island region of Sumatra, take the largest toll on the air quality of not only Malaysia but also southern Thailand and Singapore. These farmers in Sumatra continue to use ‘slash and burn’ farming practices, which despite being highly illegal, continue to occur ritually year after year. The smog and haze that comes from these often make their way directly over to Malaysia, with disastrous consequences on the health of all of its citizens.

When is pollution at its worst in Selangor?

As touched on briefly previously, Selangor is subject to fairly consistent levels of ‘moderately’ rated pollution year-round, with both Klang and Shah Alam coming in with PM2.5 readings between 15 to 20 μg/m³ throughout the various months of the year. PM2.5 refers to particulate matter that is 2.5 micrometers in diameter, or of lesser size, and is roughly 3% of the width of a human hair, making it incredibly small and therefore harmful. Due to its potency as an air pollutant, it figures largely when calculating the overall levels of air quality.

The month that came in with the worst readings across all 5 cities ranked in Selangor was September, due of course to the aforementioned forest and farmland fires occurring in Indonesia, with their vast swathes of smoke and haze being pushed over by winds to create this trans-border pollution problem.

Klang came in with a September reading of 43.7 μg/m³, whilst Shah Alam came in with 45.5 μg/m³. Petaling Jaya and Banting both came in with readings of 45.1 and 42.1 μg/m³ respectively, with the cleanest city in Selangor state, Kuala Selangor, coming in at 38.6 μg/m³. These readings all show that the pollution spikes were fairly consistent with each other, with Shah Alam coming in with the worst reading, although by only a small margin. Due to these heightened readings of PM2.5 and PM10, it would be of great concern for citizens and travelers alike to take preventative measures, such as staying indoors and avoiding outdoor activity during the month of September. Other initiatives include staying up to date on daily pollution forecasts via air quality maps as available on the IQAir website, as well as the AirVisual app.

What are some health problems associated with pollution in Selangor?

Whilst many months do not present significant health issues to those exposed to them, with readings such as 14.4 μg/m³ or 16 μg/m³ perhaps being able to aggravate symptoms of asthma in those who suffer from it or cause mild skin and throat irritation to those who are sensitive to such chemicals, the month of chief importance is of course September, with incidences of vast clouds of smoke and haze covering the sky and blocking out distant buildings being warning enough that the quality of air is extremely poor. As such, the related health issues that are mentioned may still occur during the rest of the year, but have a highly elevated chance of occurring in September.

To mention a few of these conditions, they would include ailments to the respiratory, cardiovascular and circulatory systems, with incidences of lung cancer being increased, as well as chances of developing chronic obstructive pulmonary disease (COPD), an umbrella term which includes within it a variety of respiratory related diseases such as bronchitis, emphysema, asthma as well as a reduction in full lung function. With fine pollutants such as black carbon, due to its small size it can make its way deep into the tissue of the lungs and penetrate into the alveoli, the tiny air sacs that are responsible for moving oxygen into our bloodstream. This tiny particulate matter can accumulate here, reducing the lungs ability to fully take in oxygen thus exacerbating breathing difficulties. These accumulations can also cause lung cancer to take hold if exposed for long enough periods of time, as well as chest infections over shorter periods of time.

To move out of the pulmonary disorders spectrum, PM2.5 also has the ability to enter the bloodstream via the lungs, and makes its way round the body via the circulatory system. This has a number of problems associated with it (due to the obvious nature of having dangerous materials in your blood) which can cause damage to the blood vessels, heart diseases, arrythmias as well as increased chances of heart attacks.

Damage can also occur to the hepatic and renal (liver and kidney) systems, due to their role as filtration units in the body. Reproductive health can also be affected severely if exposed for long enough periods of time. For at risk people such as mothers carrying unborn babies, there is the chance of miscarriages to occur, as well as birth defects, low birth weight and early delivery, all of which can increase the chance of infant mortality.

Breathing fumes from burning plastic (as one may find in the air near a plastic recycling or production plant) can cause severe headaches as well as damage to the nervous system. These are but a few of the wide variety of symptoms that may occur to those exposed to high pollution levels (such as the ones that occur in September), with exposure amounts and lengths correlating directly with the chance of such illnesses occurring, and their severity.

What is Selangor doing to improve its air quality?

As with neighboring Kuala Lumpur, initiatives towards improving public transport have become more apparent and necessary in recent times, with more money and resources being put into improving the public transport sector, in an attempt to get people to stop relying on their personal vehicles so much and thus reduce the levels of year-round pollution that Selangor and other states see. In regards to the fire problems stemming from Indonesia, cooperation on an international level continues to take place, but an actual definitive method to bring these practices to an end and thus stop the September haze from occurring has yet to be fully put into place.

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