Xiwen Yeoh Articles

on 7 Oct, 11:10
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Xiwen Yeoh

Oxygen — Identification of Water Pollution

Oxygen — Identification of Water Pollution

“Do you know why do we need to measure the oxygen concentration in the water?”
“To test whether it is enough for the fish to breath?”

Ok that was a sample answer most probably will be given by normal people who are not into Chemistry or Water Science. The basic knowledge that we know about oxygen is, all living things need oxygen to breath and stay alive. From the perspective of Environmental Science, the oxygen concentration in the water means something more, and we call the oxygen ‘dissolved oxygen’ (DO). Oxygen is soluble in water, that’s why aquatic life can breath underwater!

(image taken from Michael Prescotts’s Blog)

Conditions Affecting DO Concentration in Water

At normal room temperature and pressure, oxygen, like any other gases, is the most stable in gaseous form. So they can easily escape from the water into the atmosphere if the water condition is not ‘favourable’ for it to remain in dissolved form. These are a few key conditions that affect the solubility of oxygen in water:


When we boil the water, DO absorbs heat and expands, making it much lighter than the water and thus leading to the ‘escape’ as it rises. This is the reason we don’t change the water in fish tank with boiled water, which is deprived of oxygen.

Atmospheric pressure

At a higher altitude such as on a mountain, we might not be able to breath as easy as when we are at sea level due to low atmospheric pressure up there. Because of the low oxygen concentration in the air under low atmospheric pressure, the DO concentration in water will be lowered as well.

Salinity (saltiness)

Salty water contains salt, which is ionic compound. These ionic compounds will attract and attach to water molecules, causing the water to hold less oxygen molecules, which are neutral. Thus, sea water can dissolve less oxygen compared to fresh water!
[if you are interested to know, the solubility of oxygen in fresh water (at 25°C & sea level) is 8.3 mg/L while in sea water, it is 6.7 mg/L]

(image taken from Stevens Water website)

Relating DO Concentration with Indication of Water Pollution

Sometimes, the fastest way to wipe out the entire aquatic life in a region is not through poisoning them with toxic pollutants, but through taking away the oxygen in the water which is vital for life. The only consequence of depleted oxygen in water towards the aquatic life is death. According to the National Water Quality Standards for Malaysia & Department of Environment Water Quality Index Classification, water belongs to Class I should have DO concentration more than 7 mg/L. What does it mean when the DO concentration is lower than that?

Accumulation of Organic Matter

Organic matter sounds like good stuff for the growth of plants, but when they accumulate in the water, it turns out to be not so good. Chemistry-cally speaking, organic matter is made of carbon chains which will be break down by microorganisms into simpler form so that it can be used as nutrients. The carbon will be converted into carbon dioxide which requires oxygen as shown in the equation below:

C  +  O2  à  CO2

If there is a lot of organic matter, there are a lot of carbons. So a lot of oxygen will be used, causing the oxygen in the water to run low. By doing some simple calculations, you will know how many grams of carbon will immediately consume 7 mg of oxygen in 1 L of water. These organic matter might come from the animal wastes of farms, discarded internal organs from slaughterhouses, dead animals carcases or plants etc.

Accumulation of  Nutrients

Accumulation of nutrients in water can be caused by the accumulation of organic matter, but it can be also resulted from the direct discharge of nutrients into the water, most probably due to the excessive chemical fertilizers used in farms that are washed into the water by rain. The nutrients can come from the detergent we use too (to be more specific, the nutrient mentioned isphosphate)! It is true that the aquatic plants will benefit from these excessive nutrients available for their growth, but there are some ‘bad guys’ who will feast on these nutrients as well and quickly multiply in number. These guys, again, are microorganisms. They are given more incentives to grow their population, thus raising the competition of grabbing any oxygen available with other aquatic life.

Infestation of Microorganisms

This one is obvious, to put it in a simpler way, the water will be too crowded with microorganisms gasping for air to breath. It can be indirectly caused by the two points I mentioned above, but same as nutrients, the direct discharge of microorganisms especially bacteria into the water happens too, where untreated sewage effluent is channeled into the water. Where does the sewage come from and what kind of microorganisms it contain? Er…it comes from your toilet…?

How about Phytoplankton that Produces Oxygen?

Phytoplankton behaves just like plants living on land or in the water. They carry out photosynthesis to produce oxygen, so they constantly supply the water with the goodness all aquatic life will be happy with. Like other aquatic plants, they react positively towards the excessive nutrients available in the water and all of the sudden they bloom, covering the water surface with a tint of green (usually). There comes the disaster. The aquatic plants at the bottom of the water will not get enough sunlight as the phytoplankon covers up the water surface. Eventually, those plants die and the story begins with accumulation of organic matter, moves on to the accumulation of nutrients, and then the infestation of microorganisms. There goes all the oxygen. This phenomenon is called eutrophication.

(image taken from Slide Player)

Differences between DO and Biochemical Oxygen Demand (BOD)

If you have not heard of DO, you might not have heard of BOD as well. DO is the current dissolved oxygen concentration of the water, while BOD is the rate of the dissolved oxygen being consumed by the microorganisms in the water. So, if DO goes up, BOD will go down. To perform this analysis, the water sample will be collected using BOD bottle, a glass bottle with a glass stopper which can make sure that no air goes into the water sample collected.

The legendary BOD bottle. There is another version which is in amber colour to avoid penetration of sunlight so that the microorganisms in the sample will not carry out photosynthesis which will influence DO reading. We should always hold the bottle by its neck if we are going to perform analysis related to the microorganisms in the water because our body temperature might cause changes to the results (microorganisms like warm environment).

Then we will take the initial reading of the DO concentration which will be performed immediately after collecting the water sample. The analysis can be done either with the traditional Winkler method, or with the modern technology – DO meter. Winkler method involves using a chemical which captures dissolved oxygen in the water so that we can proceed to analyse how much oxygen-capturing chemical has been used to calculate the concentration of dissolved oxygen. Ok that sounds like too much work. So it’s faster if we use the DO meter!

The DO meter, the most convenient invention ever compared to the traditional Winkler method! By just inserting the probe into the sample, the reading can be recorded when it becomes stable.
Thanks to the improvement on the instrument we are using now, this DO probe has a mini stirrer attached to it so that we don’t have to stir while taking the reading from the DO bottle.
DO meter probe in action! It fits so well into the BOD bottle that we don’t have to hold it and air in the surrounding won’t get into the bottle and affect the actual DO content in the sample!

Up to this point, we have just measure the DO, not the BOD. The BOD bottle containing the sample will be sealed and placed inside an incubator at 20°C for 5 days, giving the microorganisms some time to use the oxygen in the bottle so that we can measure the DO again to see how much oxygen has been used up in the 5-day time.


Now you know the reasons we shouldn’t throw food waste into the drain or wash the detergent into the river. Whatever input we give to the water, there will be an outcome which might not be desired to everyone.


1) Radojevic, M. & Bashkin, V. N. (1999). Practical Environmental Analysis. Cambridge, UK: The Royal Society of Chemistry.
2) Manahan, S. E. (2009). Environmental Chemistry (9th Ed). Florida, United States: CRC Press.


P/S: This post was taken from the Confessions of An Environmental Student blog.

on 4 Oct, 19:07
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Xiwen Yeoh

Haze – Air Pollutant Index (API)

Haze – Air Pollutant Index (API)
(screenshot taken from Air Pollutant Index of Malaysia)


The sun has been less scorching and the scenery has been blurry for almost a month. Holding an umbrella, I walked towards the faculty, trying my best to breath through nose despite of the burning smell, hopefully this amazing creation given by God can filter away the smoke suspending in the afternoon air during this hazy season. As a person with over 18 years of sinus experience, minimizing exposure towards the haze is a must to prevent triggering allergic condition but this trans-boundary man-made phenomenon has cornered many of us to the state that we have to stay in air-conditioned room whole day long, if it is available. Simply staying indoor to avoid the haze is no longer a temporary solution unless you shut off all the ventilation you have in the building. Haze has brought so much discomfort to our daily lives but how much do we actually know about the figure that we have been watching closely every day hoping for school closing to get information about the haze condition?

Development of Air Quality Guideline in Malaysia

1989 – Recommended Malaysian Air Quality Guidelines (RMG)
1993 – Malaysian Air Quality Index (MAQI)
1996 – Air Pollutant Index (API)
[API closely follows the system of Pollutant Standards Index (PSI) of United States, now known as Air Quality Index (AQI)]

Air Pollutant Index (API)

We have been using the API system since 1996 (just found that I am older than this system, hahaha) and I believe that most people only know that the higher the reading of API, the worse the air quality (don’t even border to remember the exact figure for each category, unless the lecturer is going to test us in the exam). As you can see in the image below, as soon as the API exceeds 100, the air is considered as unhealthy. Unlike what is usually displayed, API does not stop at the status hazardous (>300). If you refer to A Guide to Air Pollutant Index in Malaysia published by the Department of Environment in 2000, if API exceeds 500, it will be declared as emergency state and the public will have to follow the order of National Security Council. We have experienced school closing and many locations reached unhealthy state which is already bad enough (think about the sore throat you are having now!). Can you imagine thecondition in Indonesia where API is over 1000?

You might find that some colour coding for API you get on internet is different from this one. The one which starts the colour with green is actually AQI. So make sure that you don’t mixed up both similar systems.
(image taken from Google Play)

Calculation of API

This was a really tricky question to me because even thought I am an environmental student I had never thought of knowing about it at all (credits go to Dr. Tengku who made me feeling ashamed of not knowing)! API is not only a measurement for the severity of haze (it should be called suspended particulate matter), but also for the other 4 pollutants: ozone, carbon monoxide,nitrogen dioxide and sulphur dioxide. Data will be collected using 52 continuous air quality monitoring stations set up throughout Malaysia (yes, we have only 52, you can now imagine the cost needed for each equipment). Then, the sub-index of each pollutant will be determined respectively according to the standards given. From the 5 sub-indexes we get, the highest one will be the API figure (of course the pollutant responsible towards this reading will be stated.

What to do then?

There is no way we can fly over to Indonesia helping them putting out the fire. Besides doing self-protection (wearing mask, staying indoor etc.) and complaining regarding how bad the haze is on Facebook, we are just waiting and praying for this hazy season to come to an end. The effort of a single person (stop smoking, stop open burning, reduce driving etc.) might be too small to make a difference, but there are a few NGOs who are working hard on solving this problem by educating the public regarding haze and also encouraging the people to stand up for our rights of clean air who need our support.

Greenpeace Southeast Asia

World Wildlife Fund (WWF) Singapore & People’s Movement to Stop Haze (PM.Haze)

Well there are more to explore on this topic (what is haze, peatland fire, slash and burn agriculture etc.) and all the information is accessible on Google. Haze is a problem that has been haunting us every year. Turning a blind eye towards the already blurry vision is not a solution. Lets get started by educating ourselves, and then figure out the little things that we can do to contribute to this bigger fight towards haze.

Photo taken last year as I cycled to class. It seems that this problem has been on-going  for years but why do we forget about it easily after the hazy season ended and embrace the next one one year later?


1) Department of Environment. (2000). A guide to air pollutant index in Malaysia (API) (4th ed.). Kuala Lumpur, Malaysia: Department of Environment.

2) Department of Environment. Air pollutant index of Malaysia. Retrieved from http://apims.doe.gov.my/

P/S: This article was taken from the Confessions of An Environmental Student blog.

on 26 Sep, 13:51
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Xiwen Yeoh

BPA – Why Our Plastic Bottles Need to Be BPA free?

BPA – Why Our Plastic Bottles Need to Be BPA free?
(image taken from Clean Body Living website)

We often notice this sign saying ‘BPA free’ when we walk down the aisles of hypermarket displaying various types of plastic drinking bottles. It seems like a must for the prestigious plastic bottle manufacturers today to put the sign on their products so that customers will be like ‘oh ok, BPA must be something nasty, since it says it is free from this substance, it must be safe to use’, without actually knowing what BPA is.

Back to 1891…

BPA stands for bisphenol A, a chemical substances that is used in manufacturing ofpolycarbonate plastic (PC) derived from petroleum. It was first synthesized as early as 1891 by a Russian chemist named Aleksandr Dianin (but it was first mentioned in scientific paper in 1905 by Thomas Zincke from Germany, and of course it was written in German that I couldn’t understand the content). Only after over 60 years, in 1953, two scientists – Dr. Hermann Schnell and Dr. Daniel Fox – respectively discovered PC through the reaction between BPA and phosgene. Both of them were amazed by its durability and strength, and continued developing this polymer. At the beginning, this material was used in electrical and electronic appliances and then slowly moved into industries producing plastic bottle and lining of canned food.

So it was ‘safe’ to be used at that time?

During early 1960’s, United States Food and Drug Administration (FDA) approved the usage of PC in food packaging. In 2008, they released a statement saying that BPA was safe to be used in food packaging without posing an acute health risk to the general population until 2013,amendment on food additive regulations was made that the usage of BPA in baby bottles, sippy cups and baby formula packaging is no longer authorised. However, it is still considered as safe to use BPA in other normal food packaging in United States.

Actually in 1930’s, British chemist, Charles Edwards Dodds had his major scientific discovery in synthetic artificial oestrogen and he already recognised BPA as one of them. However, there was no evidence about its threat towards human’s health so it didn’t receive much public’s attention.

You might want to look at it the chemistry way. Estradiol is one of the estrogens produced in human body.
(image taken from My Wilde World blog)

How dangerous is BPA?

BPA is considered as one of the endocrine disruptors which obstructs the normal functioning of hormones in human body by mimicking estrogens, a type of female sex hormones. They interact with the estrogen receptors in human body, causing our body to misunderstand that we actually produces those estrogens, leading to various physiological effects and health problems. If the concentration of BPA is very high, it will inhibit the function of androgens, which is the male hormones (I believe you can imagine the consequences).

One study shows that BPA can be metabolised by human body and be eliminated through urine (therefore urine test is carried out to measure the exposure rate). So low level of BPA might not bring harm to human body as long as the metabolism rate of your body is good, this makes newborn babies more susceptible towards the impact from BPA, but not foetus in mother’s womb because mother will do the metabolism work before transferring the blood to the foetus. However, according to the Society for Endocrinology, there are a few journals relating BPA to cancers such as breast cancer and thyroid tumour.

Maybe before we know what is the negative effects brought by BPA to human body, we should look at how we are exposed to this chemical. Basically our exposure to BPA is though ingestion, where the chemical leaches from the container or packaging into the food we consume. A few laboratory studies have been done to investigate whether BPA will leach from the PC plastic under normal use or other conditions. It shows that high temperature, acidic or alkaline environment increase the rate of polymer degradation, resulting in the leaching of BPA with higher rate, which is quite logical, that’s why we don’t usually use plastic container for hot food. However, when the PC plastic container was simulated normal use (rinsing, washing, storing food simulating solvent, room temperature etc.), BPA was still found leaching from the plastic.

How about cold food? Maybe if we store only cold stuff using PC plastic, the leaching can be prevented? Well, a study was done in Harvard College where 77 students were asked to avoid using PC plastic container for food and drink consumption in one week, and then take cold bevarage from PC plastic bottle for another week. Their urine was collected during the end of the first week and the end of the second week for BPA analysis. The results showed that the urinary BPA concentration had risen for 69%! This certainly surprised me that this light-weighted and heat-resistant plastic is actually not as stable as claimed.

(image taken from Plastic Free Bottle website)

How do we know whether the plastic containers contain BPA?

It is clearly stated in the image above (maybe slightly blurry) on the types of plastics and their main components. PC plastic falls under the code 7, so you may now check on the bottom of the plastic bottle you are using now and start to feel worry. As I said earlier in this article, there are many plastic bottles sold out there displaying the proud sign of ‘BPA-free’. That doesn’t mean that ‘hooray the bottle is safe to be used’ because the BPA component of the bottle might be replaced by other chemical with unknown toxicity. So…… To be safe, use high quality stainless steel (no acidic liquid please!) or glass as your regular water bottle, if you don’t mind them being heavy. They are certainly the safe options!


Caliendo, H. (2012, June 28). History of BPA [Article]. Retrieved from Packaging Digest website: http://www.packagingdigest.com/

Hengstler, J. G., Foth, H., Gebel, T., Kramer, P. J., Lilienblum, W., Schweinfurth, H., Völkel, W., Wollin, K. M. & Gundert-Remy, U. (2011). Critical evaluation of key evidence on the human health hazards of exposure to bisphenol A. Critical Reviews in Toxicology, 41 (4), 263 – 291.

Miller, G. T. & Spoolman, S. E. (2012). Environmental hazards and human health. In Living in the environment (pp. 427 – 454). Canada: Yolanda Cossio

Carwile, J. L., Luu, H. T., Bassett, L. S., Driscoll, D. A., Yuan, C., Chang, J. Y., . . . Michels, K. B. (2009). Polycarbonate bottle use and urinary bisphenol A concentrations. Environmental Health Perspectives, 117 (9), 1368 – 1372.



P/S: This article was taken from the Confessions of An Environmental Student blog.

on 15 Sep, 21:51
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Xiwen Yeoh

International Greentech & Eco Products Exhibition & Conference Malaysia 2015 (IGEM 2015)

International Greentech & Eco Products Exhibition & Conference Malaysia 2015 (IGEM 2015)

The International Greentech & Eco Products Exhibition & Conference Malaysia (IGEM) is here again in Kuala Lumpur Convention Centre (KLCC) from 9th to 12nd September 2015! For IGEM since year 2011,  Expomal International Sdn Bhd had been the host until this year, when this annual event was taken over by the Ministry of Energy, Green Technology and Water Malaysia (KeTTHA) (The first IGEM was held in 2010 by Green Purchasing Network Malaysia). The theme for IGEM 2015 is Powering The Green Economy which covers the following 5 key areas:


Compared to the previous two years which I attended, the theme this year looks more interesting but the number of exhibitors are much more lesser (I believe it was due to the economic crisis we are facing now where many companies pulled out), in which a lot of the exhibitors are from the solar energy section. I would like to feature one company from each of the key areas above.


(photo taken from Solar NRJ website)

Green Energy

Installing solar panel on our rooftop sounds like a worthy investment but many of us do not know how does the whole thing actually work. Will it be expensive to get one? What if I need electricity when there is no sun light? So I talked to the sales engineer of Solar NRJ Sdn Bhd, and got some useful information. For the latest technology of solar panel, the efficiency achieved in harvesting sunlight is 16-17%, which is considered as ok and profitable (imagine if it reaches 100% in the future). However, we do not actually use the electricity produced from our solar panel. The electricity still comes from Tenaga Nasional Berhad (TNB) and the electricity generated from your solar panel will be sold to them directly, which means, you still have to pay your monthly electricity bill while TNB will pay you for the electricity you sell to them.

The starting cost to install a solar panel ranges from RM 30k to RM 100k (might be enough to get a car), depending on the types (on rooftop, integrated with building structure etc.) and also size of the solar panel. Despite of this difficulty in getting started, you will profit from your solar panel after 6 years of installation! Solar panel today requires low maintenance where you get 10 years of warranty for the frame and 25 years of warranty for the solar cell (the working part of the solar panel). After 25 years, the performance will drop to 80% of the original efficiency but it is still good to work.

Solar NRJ Sdn Bhd was actually promoting another type of renewable energy which is still under development – generating electricity using water! Rain water will be collected where it will be broken down into hydrogen gas and oxygen gas (rain water = water = H2O). The hydrogen gas will be used as the fuel to generate electricity. The whole mechanism is quite complicated that I am not sure how to explain, hahaha. It will be really cool if rain water can be utilised just like sun light!


(photo taken from Rapid KL website)

Green Transport

When people talk about green transport, usually it is about electric car or car running on natural gas. But to me, even though if the vehicles stay alive using ordinary petrol, it is green as long as many people share it at the same time – the public transport such as buses or railway transit (no point considering electric car as green if everyone drives one, the traffic will be horrible). Back to the main topic, cars running on natural gas is getting common in Malaysia that we even have buses running on natural gas because natural gas burns cleaner than petroleum, so there will be less emission. To make things better, electric bus is being introduced and operated now in Malaysia since June!

If you have ever been to Sunway, you might notice some fly-overs specially made for some kind of buses. It is the Bus Rapid Transit (BRT) – Sunway Line. Manufactured by BYD Company Limited from China while operated by Rapid KL, these electric buses have their own lane built over the roads in Sunway, which means no congestion and environmental friendly due to low emission. Well I was quite surprised when I saw this system being exhibited in IGEM but I have not heard of or seen it at all! I wish I get the chance to try it out.

As the cities are getting more and more congested with traffics and people coming to work, we definitely need more public transport which are reliable and frequent. We currently have Light Rail Transit (LRT-including Monorail), and Malaysian Railway (KTM) around Selangor area, Mass Rapid Transit (MRT) is in the progress of construction as well! Hopefully in a couple of years, by the time I need to work, the system is improved and less cars on road!


(image taken from Green Building Index website)

Green Building

Have not heard about green building? Yup it is not something common for the public but it is a growing trend as people opt for a more sustainable living. Green Building Index (GBI) is a tool that does the rating for buildings based on these 6 criteria: energy efficiency, indoor environmental quality, sustainable site planning & management, material and resources, water efficiency and innovation. To make it easier to understand, a green building needs to use less electricity (by utilising sunlight for lighting and good ventilation), has a comfortable surrounding, located at a strategic area with convenient public transportation, built by environmental friendly materials, uses less water (by harvesting rain water etc.) and…is designed innovatively.

The developer of the building will submit the application to be rated by GBI and they will be assessed twice – paperwork and on site. Those buildings will be assessed once every 3 years to make sure that they keep up to the standards. Till the end of December 2014, incentives such as tax exemption and stamp duty exemption will be given to the buildings that were granted the GBI certificate. For now no incentive is given but they are in the progress of setting things up.

During this IGEM 2015, GBI brought a good news! The surface area of buildings being certified as green buildings has reached 100 million square feet! I believe that buildings especially those commercial and industrial ones should follow the guidelines as they consume lots of energy and resources for a long period of time during the day (or even night!). This will certainly help in sustainable development of the country.


(image taken from DRB-HICOM Facebook page)

Solid Waste Technology & Management

Collection of solid waste has become a big business as more and more private companies involve themselves in this field. We might be familiar with companies that collect household wastes such as Alam Flora Sdn Bhd, e-Idaman, SWM, Trienekens and our local authorities, there are other companies that collect industrial and commercial wastes where the amount of solid wastes is enormous! DRB-HICOM Environmental Services (dhes) is a company managing solid wastes mainly for the industrial sector but they do collect recyclables from the public by setting up buy-back centres, in which they pay the people who ‘surrender’ their recyclables with respective pricing according to the types of the recyclables.

They collect recyclables in a quite specific way, unlike the ordinary 3-coloured bins we see everywhere. Besides newspapers, magazines, black and white papers, mixed papers, boxes, aluminium, tin and plastic (yes they are really specific), they also collect tetrapak (drinks carton), electronic wastes (old electrical appliances, handphones etc.) and also batteries. The thing that attracts me the most is, they collect used cooking oil as well!

Dhes works together with Uni10 Energy Sdn Bhd to run this waste cooking oil collection program in Putrajaya (6 locations) and Cyberjaya (1 location). These collected oil will processed into biodiesel instead of re-entering the the food chain or causing water pollution. The person in charge told me that the response is quite good especially from the hawkers (I do admit that the price offered is quite attractive compared to old news papers, hahaha). Recycling centres are very common in our neighbourhood, but they should be upgraded into more comprehensive ones so that we can truly reduce the solid wastes going into the landfill.


(photo taken from IHI Corporation website)

Clean water Technology & Management

Water is a very important resources which is involved in every part of your life and every thing that you use, including the electricity where the generator needs water to cool down (we call the indirect use of water ‘virtual water‘). Due to overuse and influence from climate change, our water supply is lesser and lesser. Even though we have plenty of water in Malaysia as a tropical country, but we still faced water crisis in Selangor a few times earlier this year. So, waste water treatment is a must to recover some of the water resources besides preventing contamination of other clean water.

IHI Enviro Corporation has a technology called IHI-IC Reactor which is used to process industrial waste water. The interesting thing is, the waste water is not only treated, but also fully utilised to harvest green energy in the form of biogas. It is a huge cylindrical-shaped structure where the waste water will enter from the bottom, go upwards passing though separator into a pipe (and some mechanisms that I don’t understand), reach the top to release the biogas. Then the treated water will be discharged from the top (killing two birds with one stone!) while the rest will circulate downwards through a pipe back to the bottom. (I should have spent more time at this booth to understand the whole mechanism ><)

on 10 Aug, 15:57
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Xiwen Yeoh

Solar Energy in Malaysia, Why Not?

Solar Energy in Malaysia, Why Not?

Most of the university students in Malaysia are having a two-month semester breaks now where we could have gone for a short trip at the beach or a vacation to some heritage places. However, I am still sitting at home watching the laptop screen playing computer games instead of hanging out with friends somewhere close to nature. I did go out, to shopping centres, or anywhere with air-condition. We have to admit that the scorching sun is a major turnoff for those who do want to go out (of course there are people who are willing to brave through the sunlight), but the photon particles emitted by the sun is something worth harvested especially in tropical country like Malaysia in order to reduce electricity generation using fossil fuels.

The estimated amount of electricity that can be generated in Malaysia. This result was calculated using the solar calculator of the National Renewable Energy Laboratory of  U.S. Department of Energy.


This is how a basic solar panel work: photons from sunlight hit and knock off the electrons from the solar panel, which moves through the wire to reach the battery or the appliance that it powers, and then return to the solar panel to displace the electrons that were lost previously. It is like a moving current being pushed by sunlight continuously as long as sunlight is available. The stronger the sunlight, the greater the electricity that can be produced, which depends on the efficiency and the surface area of the solar panel as well. For countries located at the equator like Malaysia, we are at the most strategic location to harvest energy from the sun. By using the solar calculator, it is estimated that 4 570 kWh of electricity can be generated by a solar panel with an area of 25 square metre and an efficiency of 16% (this efficiency might sound low, but it is actually the normal efficiency for a ordinary solar panel). This 4 570 kWh of electricity can light up 4 570 of 100W light bulb for 10 hours, to make it easier to understand, an average of 12.5 light bulbs can be powered for 10 hours per day per year. Well, this amount of energy might not be enough for a city dweller, but it can certainly displaced some of the energy we obtained from fossil fuels.

Rooftop solar panel. (photo taken from Green Solar Cafe website)

Recently, a new law has been established in France to require every new building constructed in a commercial zone should have rooftops partially covered by solar panels or plants. This is a good start to make solar energy into something common that we won’t go like ‘whoa you have a solar panel at your home?’ (France is a temperate country!). Since the rooftops are most likely to lie barren on our houses, why don’t we make good use of the spaces and harvest some sunlight?

on 30 Jul, 15:21
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Xiwen Yeoh

Climate Change and Health – A Malaysian Perspective

Climate Change and Health – A Malaysian Perspective

When we are talking about environmental issues (rising sea level in Bangladesh, river pollution in India, destruction of coral reef in Australia etc., just to name a few), we tend to just shrug it off because they have nothing to do with us there is nothing we can do about it. However, when it comes to health issues, people will be sharing information and tips how to prevent getting cancers, heart diseases and the list goes on never-endingly. We are so enthusiastic in protecting our body from harms by seeking medical or nutritional consultancy, but somehow we left out the whole chunk of ice berg that directly determines our health – the environment. Although there is no statistical evidence in our country that proves that climate change is bad for our health (at least not yet), I have highlighted some health issues which might be worsen by climate change.

Health issues impacted by climate change

1) Water-borne diseases

Prolonged rainy season due to climate change can cause flooding at low-lying ground. Malaysia experienced the worse flood in Kelantan last year which hit the level of 34.17 metres. Besides its direct threat towards human’s safety, flooding causes the spread of water-borne diseases such as leptospirosis and typhoid as flood victims spend a lot of time being close to or in contact with the contaminated flood water (flood water can’t be clean as it brings out water from the drains as well as the sewage system).

The flood in Kelantan last year. Flood makes you more susceptible to be infected by bacteria carried by the water. (photo taken from The Malay Mail Online)


2) Respiratory diseases

On the other side of the extreme weather caused by climate change, it’s the prolonged drought. Forest fires that are ignited by the dry spell bring lots of haze into the human-populated areas. The ‘seasonal’ haze in Malaysia comes mostly during drought and becomes worse with the lack of rain during the long period of time that can clean the air by bringing down the particulate matter. Particulate matter suspended in the air will choke our respiratory system, triggering breathing difficulties and asthma especially.

A blurry scenery of Kuala Lumpur city. How much haze can we handle each year? (photo taken from Medicine Malaysia)


3) Heat stroke

Malaysia is a tropical country where hot weather is considered as a daily phenomenon and not much concern is placed in the danger of the heat. Temperature on Earth worldwide is predicted to continue rising (it is rising now), even though tropical countries experience less impact on this, eventually heatwave will become common here. There were deaths caused by heatstroke happening here so it is something that we should pay attention to.

The sun that is beating down might kill you before you knowing. (photo taken in 2012 in Selangor Matriculation College)


4) Mosquito-borne diseases

Dengue fever has been endemic in Malaysia despite of the effort done by the Ministry of Health. It will only get worse if the Earth’s temperature continues rising as a higher temperature facilitates mosquitoes and also virus activity, which in turn facilitates the transmission of mosquito-borne diseases especially Dengue fever. This year, the number of Dengue cases has reached the highest point in the Malaysia’s history with more than 40 000 cases in the first six months.

The infamous Aedes mosquito. There is no vaccine for Dengue fever yet and there are a total of four strands of virus. (photo taken from The Star Online)


5) Paralytic shellfish poisoning (PSP)

Warmer sea water creates a favourable environment for algae bloom. Normal algae bloom might seem harmless to human health (but it is fatal for aquatic life), however red tide is a different story. Certain species of plankton in red tide will secrete toxins that will be taken up by shellfish and in turn poison the people who consume the contaminated shellfish. Red tide can be found in Malaysia, even though cases of PSP are rare, with increasing frequency of red tide happening, the risk of having toxic plankton rises too.

Red tide spotted at South China Sea in 2012. (photo taken from The Star Online)


Studies published by United States Environmental Protection Agency (USEPA) and National Institute of Environmental Health Sciences (NIH) have shown the relationship between climate change and health problems including cancers, cardiovascular diseases, neurological diseases, mental health and several more that are not covered in this article due to lack of data from Malaysia. For now, maybe we still don’t find that the effect of climate change very obvious yet, but it is always wise to prevent it from happening rather than trying to save ourselves when things already happen. Temperature is a critical element that can alter the environment and  also our body physiologically. We should look into the importance of climate change prevention to ensure that our health is guaranteed.


Read more here:

A Human Health Perspective on Climate Change – NIH

Climate Impacts on Human Health

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MESYM.com is a crowd-sourced platform and a living database for environmental movements in Malaysia. There are many good actions being done out there. Our goal is to bring them together. We connect the green dots.