Coordinating LED Night Illumination in our National Infrastructure

ADJOURNMENT MOTION

The Leader of the House (Ms Grace Fu Hai Yien): Mr Deputy Speaker, Sir, I beg to move, "That Parliament do now adjourn."

Question proposed.

Coordinating LED Night Illumination in our National Infrastructure

7.20 pm

Dr Tan Wu Meng (Jurong):Mr Deputy Speaker, as the sun sets outside this House, it seems timely that we consider the night, the colour of the night and how we light up the night.

Over the past 10 years, we have seen improvements in lighting technology. Light-emitting diodes (LEDs) have become more prevalent on the commercial market and have transformed the market for lighting. The lifespan of an LED is longer than that of a traditional incandescent light bulb. LEDs give out less heat, important in a tropical country like Singapore. LEDs, generally, are more energy-efficient than other types of light bulbs or even fluorescent lamps, and their energy efficiency is getting better year-by-year. They are an example of how science and technology are improving people's lives − new solutions to old problems.

Today, there are many different types of LED lights, each with slightly different shades of colour, even different shades of white. To describe the shades of white, the experts use the phrase "colour temperature". This is not the temperature of the light bulb, but if I may use the language of scientists, it is the temperature of an ideal black-body radiator giving out light of comparable colour to the light source. What does that mean? You might call it the colour of "red-hot", "yellow-hot" or "white-hot", even if the LED light itself does not give out much heat. So, we have some LEDs which give out a yellowish, warmer, more natural-looking white, or colour temperature of around 3,000 Kelvin. Some have a harsher white colour, with a little bit of blue light as well, or a colour temperature closer to 4,500 Kelvin or more.

Over the years, it has become easier for us to light up the night, but this has also brought to light new challenges as well. For example, Mr Deputy Speaker, exposure to light has been reported to suppress the production of melatonin. Melatonin is a hormone produced by the body that influences the body's own biological rhythms, what we call the circadian rhythms that tell our bodies when we feel sleepy and when we feel awake.

While any kind of visible light can suppress the production of melatonin, we know from research at Harvard University that blue light, in particular, has a stronger effect than other kinds of light. For example, blue light suppresses the production of melatonin for about twice as long as green light of comparable brightness. It shifts the circadian rhythm − the sleeping, waking rhythm − by three hours instead of just one-and-a-half hours. Some researchers have even raised concerns about whether shifting this circadian rhythm can affect eating habits and, in turn, the risk of obesity and diabetes. The research is ongoing but questions like these are being talked about. We also know that modern fluorescent lights and LEDs produce more blue light than traditional light bulbs. So, this is a growing issue.

Mr Deputy Speaker, what have other countries and other jurisdictions tried to do about these questions? If we look at the US and Europe, increasingly, there are policy suggestions proposing that the colour of light is important, especially at night. In Switzerland, the Federal Office of Public Health recommends that LED lamps should have less blue light component. The American Medical Association has also called for a reduction in the amount of blue light component in LED lights. The Harvard Medical School, in their Harvard Health Letter, has pointed out that having too much blue light at night may not be optimal for health. I am grateful to experts, such as Prof Michael Chee from the Duke-NUS Medical School, for highlighting some of these pointers.

Even in the commercial sector, even among the companies that build your portable devices, such as the Apple iPhone, has a "night mode", where the colour of the display shifts to a more yellow shade of white, with less blue light emitted.

So, why is this important to Singapore? This is because in our built-up housing estates, the colour of night is shaded by what kind of lighting we choose. Corridor light in our housing estates and in our void decks can shine into living rooms and bedrooms. It is not a short exposure. At the same time, it is also important that our housing estates are energy efficient. And our housing estates must also, at the same time, be brightly lit enough so that all residents, especially our vulnerable and elderly, are able to move about safely at night.

Mr Deputy Speaker, I am told by Housing and Development Board (HDB) colleagues that, for health and safety of lights, HDB relies upon the International Electrotechnical Commission (IEC) standard called IEC 62471. Currently, both the pure white light and warmer yellow-white light LEDs would satisfy this IEC criteria. But, at the same time, given the discussions going on in the US and Europe, it is quite possible that the consensus may be shifting in favour of warm yellow-white LED lights, lights which are less pure white but have a warmer yellow-white colour.

Mr Deputy Speaker, even if the consensus does not shift for a few more years, it would be prudent of us to consider possible future developments in the industry and future shifts in the consensus because an LED lamp, once installed, is an investment that will be around for many years, long enough to possibly become obsolete if international safety standards shift. And even if we leave aside the discussion about health implications, there is something to be said for having the night-time lighting look just that little bit more natural − a more yellow shade of white, a city at night that looks warmer and more natural.

So, Mr Deputy Speaker, I call upon the Ministry of National Development (MND) and HDB to look at this issue to consider standardising and moving towards LEDs which give out less blue light. We can do this by choosing LED lights with a bit more of a natural yellow colour, or a "warm white" colour. To ensure that our living environment is still bright enough for the elderly, HDB could also study the perceived brightness of different types of LEDs. What kind of power output is needed for a pure white LED to look as bright as a warm yellow LED, how to calibrate this, how to have these standards? And once these standards have been studied by HDB, they could be shared with other agencies as well as the private sector. And I wonder if HDB's Building and Research Institute could help look into this.

We should also encourage the Land Transport Authority (LTA) to think about having less blue light when illuminating our roads at night. Safety on the road is important. It is important that road users can see one another, can see pedestrians, and can stay out of danger. But within these limitations, we should look at how to reduce the amount of blue light given out by LED lights. With LTA's plans to replace all streetlamps with LED lights by 2022, we are at an inflection point in our national lighting infrastructure. It is not too early for us to be thinking about these questions. And in our Ministry of Education (MOE) schools as well, there may be a role for looking at warm yellow-white LEDs when replacing the older fluorescent light tubes.

And Deputy Speaker, all these could be part of a shared design language that shapes the aesthetics of our housing estates and our shared spaces throughout our little red dot. Deputy Speaker, as a little red dot on the Equator, we have 12 hours of daylight each day. The rest is night; one half of our existence. So, it matters how we light the night. The colour of night matters, and there is emerging evidence that by choosing a better way to colour the night, we can reduce the risk of casting a shadow on our sleep and our health. May we always choose well and always seek the right kind of illumination.

Mr Deputy Speaker: Senior Minister of State Mr Desmond Lee.

7.30 pm

The Senior Minister of State for National Development (Mr Desmond Lee): Deputy Speaker, I agree with Dr Tan Wu Meng that night lighting has an impact on the everyday lives of Singaporeans. Our lighting must, first, be functional, for drivers on our expressways to passers-by along our HDB estate corridors, night lighting must be calibrated to suit their different needs. Second, it must be aesthetically pleasing. It should positively shape how we perceive and interact with our estates and public spaces. And third, it has to be safe. This is important, given how pervasive night lighting is in a dense built-up city like Singapore.

To achieve this, one of the specifications we take into account is the light colour. And those of you who have bought fluorescent or LED lights will know that they generally come in three colours, as Dr Tan had described − warm white, pure white and cool white. Warm white has the least amount of blue light, giving it a yellow hue and a colour temperature of about 3,000 Kelvin; pure white has a more balanced mix of blue light, giving it a natural daylight feel and a colour temperature of around 4,000 Kelvin; while cool white has the highest amount of blue light, resulting in a harsh white colour and a colour temperature of around 6,000 Kelvin.

Light colour is important for both functionality and aesthetics. For our street lighting, LTA is moving towards pure white because it offers drivers a high colour contrast, allowing them to see better at night.

In our new HDB developments, light fittings at common areas, such as corridors, also use pure white, but for a different reason. The previous feedback garnered from residents indicated that warm white was too dim for HDB estates. Light colour can affect safety, too, as Dr Tan rightly pointed out. I have explained how LTA uses light colour to improve road safety at night, for drivers and pedestrians.

Dr Tan has cited several reports which advise minimising the amount of blue light for health reasons. Based on these reports, he has suggested we use warm white in our HDB common areas and LTA street lighting. These reports make two broad points. First, they state that long-term or high intensity exposure to blue light can damage the retina of the human eye. Second, they highlight that exposure to any light at night, especially blue light, can affect our sleep cycles by suppressing the production of a hormone called melatonin and affect our circadian rhythm or body clock. This has been linked to impaired daytime functioning and obesity.

I would like to clarify that care has been taken by agencies to ensure that the lighting installed in public places do not cause harm to the human eye. So, the first point about potential damage to the retina of the human eye is not a significant concern in Singapore, given our regulations.

Lighting in our HDB common areas and LTA street lighting follow the globally-recognised IEC standards, which Dr Tan had articulated earlier. These spell out technical and safety requirements for lighting, including the safety limits for exposure to white light. Indeed, the same report by the Swiss Federal Office of Public Health states that "commercial LED lamps represent no health risk when used correctly, in terms of the risk to human retina.

On the second point on the impact of blue light on melatonin and our sleep cycles, as Dr Tan pointed out, there is no medical consensus on the issue as yet. The reports do not rule out the use of pure white lighting in street lighting or in public spaces like HDB common areas.

And the specific implications of the reports' findings on our HDB common areas and LTA street lighting are as yet unclear. For example, the Harvard Medical School's Harvard Health Letter is based on studies which exposed people to blue light for six-and-a-half hours or longer, while the exposure of most Singaporeans to HDB corridors and street lighting by LTA is much shorter.

Apart from changing the colour of all our lighting, there may be other ways to address this issue. Indeed, one of the possible solutions mentioned by the American Medical Association is dimming LED lighting during off-peak periods. We have, in fact, already installed LED lighting with motion sensors along staircases for all Build-To-Order (BTO) projects launched since 2014, and we are testing out sensor-controlled smart lighting in the common areas of Punggol Northshore estate. Not only will this make our HDB estates more energy-efficient, but it would also minimise ambient blue-light at night.

Ultimately, we must ensure that our lighting remains functional, aesthetically pleasing and safe. The light colours of HDB common areas and LTA streetlamps are carefully selected to meet the functional, safety and aesthetic needs of Singaporeans. We should only decide how best to enhance our lighting after further study on the appropriate length and intensity of blue-light exposure at night has been done.

This, notwithstanding, I agree with Dr Tan that it is not too early for us to be thinking about the long-term implications of these reports on the health and safety of Singaporeans. We will, therefore, continue to keep a close watch on the evolving research in this area.

HDB will also take up Dr Tan's suggestion to study how to vary lighting levels or luminescence based on different colours of LED lights. This will allow us to better decide on the appropriate light colours in different settings − be it for functional or aesthetic reasons.

On its part, LTA will continue to use pure white lighting for expressways and major arterial roads for road safety reasons, because of the greater colour contrast. In the meantime, because streetlamps use high intensity lighting, LTA will study whether it is feasible to use warm white lighting for streetlamps on minor roads, especially those located in residential estates.

Deputy Speaker, the scientific research into lighting is evolving and new lighting solutions will come on the market. We will continue to take steps to find better ways to colour the night, to keep our city vibrant and safe.

Question put, and agreed to.

Resolved, "That Parliament do now adjourn."

Adjourned accordingly at 7.38 pm.