SHAH ALAM – The striking red sunsets that have recently captivated Malaysians on social media are a natural atmospheric phenomenon influenced by sunlight, clouds, and air quality.
Universiti Malaya meteorologist Prof Datuk Dr Azizan Abu Samah said the vivid colours are caused by a process known as Rayleigh scattering, which changes the way sunlight travels through the Earth's atmosphere.
"The scattering is a function of the size of the molecules and also the length of travel of sunlight through the atmosphere.
“In the early morning or late evening the sunlight will travel through a longer path of atmosphere compared to noon," he told Sinar Daily.
He said the blue sky seen during the day and the reddish hues at sunrise and sunset are both caused by the same scattering process, with different wavelengths of light reaching the observer at different times of the day.
"Molecules such as nitrogen in the air scatter more bluish light so that is why the sky appears blue.
"So during sunset and also sunrise most of the blueish colour is scattered out leaving the reddish colours. The role of the clouds is to reflect these colours to make it more spectacular," he said.
Azizan said atmospheric conditions also determine how vibrant a sunset appears.
"If the atmosphere is less polluted and has tall cumulus clouds the sunset colours will be more spectacular.
"In a polluted atmosphere the sunset will be less spectacular except maybe the sun will look more red but will not produce the colour play that you usually see by the beach," he said.
He noted that this is one reason why some of Malaysia's most breathtaking sunsets are often seen outside urban centres.
"Only those in KL miss some spectacular sunsets that occur in various regions, especially at beaches and padi fields.
"This is due to many factors like the presence of cloudy skies or a more polluted atmosphere that give a reddish tint to the sun," he said.
He added that aerosols in the atmosphere can also affect how sunlight is scattered.
"If aerosol is present in the atmosphere it will also be able to scatter longer wavelengths like the reddish spectrum and not only the blueish colour.
"So even at noon the sun appears yellowish or reddish," he said.
Azizan stressed that the colourful sunsets do not pose any health risks and should instead be appreciated as one of nature's most beautiful displays.
"No health risk. But a good feeling,” he said.
In recent days, social media platforms have been flooded with photos and videos of unusually red sunsets captured across several parts of Malaysia, prompting many users to wonder whether the phenomenon was linked to changing weather conditions or air pollution.