Light Pollution on streets

I searched “Night” + “Singapore” on Google images, and what came out were photos that look like this — dazzling with lights. I guess these image are almost like a symbol of modernity and progress,  a 24-hour global city. For instance, in recent years we see the Singapore Tourism Board promoting events such as F1 Night Race in Singapore. I hope that this will be a starting point for this blog post.

Few of my previous blog posts have mostly touched on air pollution, and I thought I would focus on something different this time round.

In this ABC Online article, “darkness” was described as an “endangered resource” — we are cutting ourselves away from the night sky, which is a “source of inspiration, meditation and reflection”. Not only are we disrupting ecosystems and wildlife, scientists have found that artificial light at night contributes to sleep disorders, which are in turn tied to many different diseases.

Light pollution, it seems, includes not just monetary costs (inefficient energy usage) but also environmental and health costs.

Some solutions proposed includes smart lighting technology (by Amsterdam-based company Tvilight), which aims to create lighting systems that responds to the amount of traffic and pedestrians in the area so as to reduce light pollution. In order words, providing what that is needed without wasting excess and necessary lights.

Is this something that we should consider? Or are we too fearful of the dark (after all, darkness is often associated with danger too) or that we will lose the vibrancy of the city?

To end off, here is a video of Earth from the International Space Station (just for fun! and for us to get a sense of how much light are we emitting from Earth).


Funnel, A. (2015). The Dark Side of Light. ABC Online. [Online]. Retrieved from: [Last accessed: 11 March 2015]


Under the Dome [Documentary]

Recently (28th Feb 2015), former Chinese journalist Chai Jing released an anti-pollution documentary, “Under the Dome”, which talks about China’s horrendous air pollution and is critical of the Chinese government’s policies which she blames for the country’s pollution crisis. She brings the audience through the issue with charts and diagrams through a presentation in a manner similar to Al Gore’s “An Inconvenient Truth”.

With the documentary going viral over just a few days, the Chinese government has imposed a ban and links to the documentary were pulled off from Chinese major video sites. The government has yet to comment on this to date.

Even though this documentary is not solely about street pollution (and is more about pollution specifically in China), I thought that this will be something interesting and definitely relevant to what we are studying in school right now. For a start, here are some issues that we should consider:

  • Why did China impose a ban on this documentary? Does that mean that what the documentary says is false or that the government is refusing to acknowledge the truth? Do they have something to hide?
  • Pollution is not simply about the physical effects of the pollutants on the environment; it is implicate in political decisions and has profound effects on both the social and economic spheres. This should prompt us to consider various factors contributing to pollution problems when assessing them.
  • Beyond the environmental effects of pollution, the internet is an interesting medium too — is it a whistle-blower? Can it prompt governments to take action? Raise awareness amongst the internet population? How can activists make use of the internet medium to bring their messages across to the wider public?
  • Of course, we should not forget that every documentary has its own biases. As such, we should not be taking in facts from documentaries (not just this one) mindlessly and should verify them before taking them as “justified beliefs”. We should also be cognisant that statistics (charts, data) can be manipulated to serve a particular purpose.

Meanwhile, here’s the Youtube link to the documentary. It is rather long (about 1hr 40mins) but it is worth the watch. I have included the version with English subtitles! Do have a look!


Chen, T. (2015). Pollution Documentary Pulled from Chinese websites. Wall Street Journal — China News. [Online] Retrieved from: [Last accessed: 7 March 2015]

Pittsburgh’s Air Pollution (1940s vs Today)

I saw this BuzzFeed article contrasting the difference in air pollution (through photographs) in Pittsburgh’s streets almost 70 years ago. (Do take a look!) The contrast is quite startling; seeing photographs of the hazy air (the outlines of buildings nearby are obscured) gives a better picture of just how severe pollution issues are in the past too.

While looking through the pictures, I felt quite happy that there is much progress for the better, and this made me wonder if it is possible for many highly polluted streets and regions to improve their air quality too. What is important to note is that measures take time — perhaps, we cannot expect air quality to improve overnight. But we can be hopeful that many decades later, there is a possibility of cleaner air.

Indeed, the Atlantic had used these pictures to tell netizens who are criticising Beijing’s air quality that it takes time, and Pittsburgh took close to a century to reduce the amount of smoke and soot particles in the air to the level it is at today. Contrast Pittsburgh’s development in the 19th century as the city, powered by coal, emerged as one of the main metalworks industries in the country with Beijing’s excessive coal powered power plants today.

This is Pittsburgh back in the 1940s. Source: [Last accessed: 1 March 2015]

After looking at these pictures, I have some thoughts (these are not necessarily referring to Pittsburgh and Beijing; I am thinking about many cities around the world in general):

1. The political will of the city/country’s authorities

After looking through the pictures, it might be tempting to say that severe air pollution around the world is acceptable for developing cities, and that they just need to be given a longer time to solve their air pollution issues because they are inevitable with industrial development. I think that it is unacceptable to say that just because other countries were able to pollute the air without much dire consequences (laws were not as strict as those today), one should be permitted to pollute the air as much as they would want to. It may be unfair for countries who are at the other end of the developmental ladder, but I feel that there is a responsibility towards not just a country’s own citizens, but citizens of the world once there is ample evidence and knowledge on tackling these issues.

That said, we should be aware of the unequal power relations on the world stage — would developed countries push the developmental ladder away from developing countries? Ideally, developed countries with the expertise and experience should provide their technological known-how for other countries to tackle the same problem they faced many years ago, but which country is entirely selfless to do that without any reservations or motives (settling a deal, etc)? I think not.

2. The situation may not have improved as much as we thought it had

For instance, back to Pittsburgh: it is reported in 2014 that the air quality is still bad despite improvements, due to shifts towards natural gas from coal-powered plants, with increases in unhealthy ground-level ozone. Soot and smoke particles may have declined, but many cities around the world are facing a new set of pollution problems which are less visible. PM2.5, carbon dioxide and nitrogen dioxide are just a few examples.


Hopey, D. (2014). Pittsburgh region still gets poor marks for air pollution. Pittsburgh Post-Gazette. [Online] Retrieved from: [Last accessed: 1 March 2015]

Madrigal, A. (2013). Aghast over Beijing’s Air Pollution? This was Pittsburgh not that long ago. The Atlantic. [Online] Retrieved from: [Last accessed: 1 March 2015]

Diesel traffic — respiratory effects on asthmatic persons

After posting about a research on diesel pollution exposure on school buses previously, I thought it will be good to look deeper into the effects of such exposure. The journal article that I looked at did not provide any particularly surprising information to me, since I already had a rough idea about how polluted diesel exhaust is, and how they pose various problems to our respiratory tracts. What this article taught me more about is some specific respiratory effects (it is from a health journal, the New England Journal of Medicine!) and some considerations when it comes to possible experimental design.

Close up picture of diesel exhaust fumes. Source: [Last accessed: 26 February 2015]

McCreanor et al (2007) did a research on the short-term respiratory effects of exposure to diesel traffic in asthmatic persons in an urban, roadside environment. What this research aims to do is to build on research from previous studies that were conducted under laboratory conditions — previous studies have not been entirely consistent and exposure to those pollutants may not reflect that of real conditions. McCreanor et al (2007) suggests that these discrepancies may be due to interactions between different pollutants, or that pollutants under laboratory conditions may have removed. Instead of conducting the research indoors, they got participants to expose themselves to diesel traffic by the streets.

They got 60 adults with mild or moderate asthma to walk for 2 hours along Oxford Street, London, and Hyde Park on a separate occasion (I briefly mentioned in my first post that Oxford Street was raised in the spotlight just recently in 2015 for extremely high nitrogen dioxide levels!). The study was limited to winter months to avoid other variables such as exposure to pollen. As expected, participants had significantly higher exposure to fine particles, in particular, PM2.5 when walking along Oxford Street. There were also higher exposure to other ultrafine particles, elemental carbon, and nitrogen dioxide. As a result, participants with prolonged exposure to air pollution by the streets recorded consistent respiratory effects such as a reduction in the forced expiratory volume in 1 second and forced vital capacity. Respiratory tracts were also inflamed after prolonged exposure, and these effects are more severe for those with moderate asthma.

Of course, having an experimental design as such will lead to a lot more confounding variables — the authors mentioned that the respondents produced symptomatic responses, but other variables such as traffic noise may have played a part in increasing stress levels, which may trigger the onset of asthmatic symptoms too.

Diesel exhaust is also cancerous — according to NHS Choices, WHO’s International Agency for Research on Cancer (IARC) decided to classify diesel exhaust as carcinogenic instead of “probably carcinogenic” in 2012 after there is sufficient evidence that diesel exhaust is a cause of lung cancer.

How bad are diesel exhaust fumes? As a reference, The Daily Mail quoted Kurt Straif, director of the IARC department that evaluates cancer risks, who mentioned that the effects of breathing diesel exhaust is of the same magnitude as that of passive smoking. (So, try not to stay indoors too when there are people smoking in the room!)

Picture of a cigarette. Source: [Last accessed: 26 February 2015]

(And since there are 2 pictures showing a lot of smoke, Diesel Exhaust + Cigarette smoke = Smoky Streets indeed! Can’t resist not mentioning the blog name, haha. Even though the contents of this blog should be much more than just this two topics!)


McCreanor, J., Cullinan, P. Nieuwenhuijsen, M.J., Stewart-Evans, J., Malliarou, E., Jarup, L. Harrington, R. Svartengren, M., Han, I., Ohman-Strickland, P., Chung, K.F., Zhang, J. (2007). ‘Respiratory Effects of Exposure to Diesel Traffic in Persons with Asthma’. The New England Journal of Medicine 357: 2348-2358.

NHS Choices (2012). ‘WHO: ‘Diesel Exhaust Fumes Cancerous”. [Online] Retrieved from: [Last Accessed: 25 February 2015]

The Daily Mail (2012). ‘Diesel exhaust fumes are ‘major cancer risk’ and as deadly as asbestos and mustard gas, says World Health Organisation’. [Online] Retrieved from: [Last Accessed: 26 February 2015]

Some updates on pollution by firecrackers

I posted 3 days ago about the likelihood of air pollution due to fireworks in Beijing during the upcoming Chinese New Year celebrations. Over the next few days, I managed to read some news updates regarding the situation. Indeed, what authorities predicted came true: real time air-quality data from Beijing recorded a sharp jump in PM2.5 levels immediately after midnight. The article on IBT Pulse tells you the whole story with a few pictures that helps illustrate the point, do take a look at the article here!

The South China Morning Post also reports that “the air quality index rose from around 50 to 456 within a few hours, with average PM2.5 levels hitting 413 micrograms per cubic metre – more than five times the national safe standard – at about 1am” (As a comparison, at 20th Feb, 9pm, Singapore’s hourly PM2.5 level is at 57 at the central area, and about the 25 to 40 range for other areas (north, south, east west); the bigger numbers are the overall PSI readings, not the PM2.5 readings. The PM2.5 readings are in a smaller print.)

Source: Screenshot by me!

Source: Screenshot by me!

Hopefully, these updates will provide you with a better picture of the pollution caused by firecrackers!


FlorCruz, M. and Poladian, C. (2015). Chinese New Year 2015 Fireworks: Lunar New Year Celebrations Spur Air Pollution Debate. International Buisness Times. Pulse. [Online] Retrieved from: [Last accessed: 20 February 2015]

Li, J. (2015). Beijing Welcomes Auspicious Snowfall amid heavy pollution over Lunar New Year. South China Morning Post — China. [Online] Retrieved from: [Last accessed: 20 February 2015]

Happy Chinese New Year! (And let’s not forget about pollution)

It’s Chinese New Year soon, and I thought I could have a post about firecrackers. In particular, firecrackers causing pollution (after all, this is a pollution blog!)

Firecrackers are banned in Singapore, but they are still rampant in cities such as Beijing. According to the International Business Times, Beijing’s city government has attempting to cut down firecrackers in the city. While this may not be such a big deal in Singapore (Firecrackers were completely banned since 1 August 1972 when the Dangerous Fireworks Act came into operation), in many other places firecrackers are still seen as part of the Chinese New Year tradition — the loud sounds and lights are believed to ward away evil spirits.

For Beijing’s case now, other than firecrackers being a fire hazard, it is a major source of street pollution with red confetti expected to be scattered across the streets, and with the weather this coming Friday (the 2nd day of the Chinese New Year) expected to be windless, city authorities have anticipated that smoke from firecrackers are likely to persist in the air for a long period of time. These smoke, a result from combustion, contains pollutants such as PM2.5, which is harmful to health. As cited by Wang et al (2007), these fine aerosols which consist of sulfur dioxide, carbon dioxide, suspended particles, and traces of heavy metal poses threats to human health. This study also highlights the problem of air pollution due to these fireworks, by drawing on the chemistry of these fireworks, and found ions, metals and black carbon in aerosol samples. Pollutants were also found to be much higher during the festive season than from other days.

Results from this report tallied with observations over other years; for instance, Channel News Asia reported that on Lunar New Year’s Eve, 2013, the concentration of PM2.5 grew from 150 micrograms per cubic metre to 346 micrograms per cubic metre within an hour due to the fireworks.

While some residents are grateful for the authorities’ decision to cut down on firecrackers, some remained disgruntled. One resident said

“If the authorities are serious about tackling pollution, they should tackle industrial pollution. Setting off fireworks is just a once-a-year event. It is not as bad as industrial pollution.” (Source: CNA)

I felt that this line of reasoning, is unfortunately, problematic. If we have to tackle pollution issues, it takes more than just managing large pollution sources, and it definitely takes more than the authorities to do their job. As citizens, we do have responsibility towards our environment — small actions such as cleaning up after our trash, using environmentally friendly cars if we can afford them, minimising our use of plastic goods, and in this case, reducing the number of firecrackers may not seem to matter, but the effects add up over the long run. Admittedly, cultural practices may be hard to change…

In any case, happy Chinese new year to all and may you all have an auspicious year ahead! 🙂

Happy Chinese New Year!


Channel News Asia (2015). Beijing Air Quality set to worsen as Lunar New Year Approaches. [Online] Retrieved from: [Last accessed: 17 February 2015]

Sim, S. (2015). Beijing Chinese New Year Fireworks spark crackdown over air pollution concerns. International Business Times. [Online] Retrieved from: [Last accessed: 17 February 2015]

Singapore Infopedia (2013).Regulating the use of Fireworks. [Online] Retrieved from: [Last accessed: 17 February 2015]

Wang, Y., Zhuang, G., Xu, C., and An, Z. (2007) The air pollution caused by the burning of fireworks during the lantern festival in Beijing. Atmospheric Environments. 41(2). pp. 417- 431.

BreezoMeter (EDIT: Not available in SG!)

I came across an article today which introduces a relatively new app (just released in January 2015) that not only allows users to know the quality of the air that they are breathing in, but also where can they find cleaner air in the city. It’s called BreezoMeter and is available on Google Play!

Apparently, it does offer suggestions of cleaner routes around the city, which will be great for people who are planning to jog or cycle around — it will be rather ironic if one tries to exercise to keep fit, but ended up subjecting him or herself to higher exposure of polluted air instead.

I thought the idea was really great as not only does it propose suggested routes, it also provides a set of advice for the user based on the current air quality. From what i observed from the pictures, air quality is represented through qualitative means (good, moderate, etc), which eliminates excessive numbers; this makes it a good app for the general public as the information that it provides can be easily understood.

NOTE: Wanted to give this app a try since ratings and reviews look good, but it does not work in Singapore, unfortunately 😦 (only available in the US). Wanted to take a look at the GooglePlay store to see if there are other apps available, and I found that the National Environment Agency (NEA) has an app, myENV, that provides data on air quality readings too (together with various different readings such as Wind, UV Index, Dengue Clusters, and so on). I still find BreezoMeter more attractive based on the description and looks/supposed functionality of the app alone. Perhaps such apps will attract more users and even achieve its goal better (users being aware of the air quality around them) if they offer additional functionality (such as suggesting exercise routes) instead of solely presenting data because there will be a greater impetus to use the app.