Air quality in Siem Reap

How bad are pollution levels in Siem Reap?

Siem Reap is a city located in the northwestern region of Cambodia, and is the capital of the Siem Reap province, the tenth largest in Cambodia, being home to approximately 1 million inhabitants, with 139 thousand of them within Siem Reap city. It is world renowned as being the home of the famous Angkor Wat temple site, a series of ancient Hindu, and later Buddhist temples that are spread out through the vast complex that houses them. They are a major touristic draw, besides being one of the wonders of the ancient world, and subsequently due to the massive influx of tourists coming to see the temple, there has been a significant rise in air pollution over the last few decades, with numbers and related issues climbing each year.

Whilst on an economic level the large scale growth of tourist visitors each year is very much beneficial (with many of the inhabitants of Siem Reap basing their livelihood around the business that tourists bring with them), in order to support this growing number, more hotels are built, more motor vehicles are needed along with the fuel and industry to keep up with the demand. Looking at some of the numbers taken in the early period of 2021, Siem Reap was seen with readings as high as 101.3 μg/m³ μg/m³, a very sizeable reading that presents a significant danger to those who respire air with such poor quality. Whilst there were lower readings also present going all the way down to 23.1 μg/m³, it stands to reason that pollution levels in Siem Reap are far below optimal, and even in the covid-19 era that has decimated tourism, the pollution numbers are still remaining high in the city.

What are the main causes of pollution in Siem Reap?

As mentioned before, one of the main causes of rising pollution levels in Siem Reap in the pre covid-19 era was vehicular fumes and emissions, with thousands of buses, cars, motorbikes and tuk tuks all ferrying people in and out of the city on a daily basis. Many of these vehicles use ancient engines and heavily outdated motorbike models, particularly in the larger tuk tuks that are used to transport bigger groups of tourists around. These older engines can leak far more oil vapors, as well as give out considerably more noxious pollutants than a newer counterpart would.

Other main sources of pollution would be construction sites and road repairs, with the city being subject to even more finely ground dust particles when areas are dug up and left exposed. Dust was an existing issue due to the topography of much of the city, with many months of dry heat causing large dust storms to build up and accumulate. When combined with the soil disruption as well as novel particulate matters that construction and repairs introduce, the issue is compounded even further.

Other problems include the open burning of waste and refuse, as well as fields or crops for the purpose of farming, more common on the outer city limits. In closing, the two main causes of pollution are vehicular emissions and dust accumulations, with the latter being more prominent in the years following 2020 and the subsequent worldwide travel lockdowns.

What are some health issues associated with breathing polluted air in Siem Reap?

With large amounts of choking dust and vehicle exhaust in the air, there is a whole host of respiratory and general health ailments that can afflict those who are subject to breathing the air over long periods of time, and even more acute symptoms making themselves present in people who are only passing through, such as higher chances of developing dry coughs, chest infections, as well as irritation to the mucous membranes and skin, with the eyes, nose and mouth all susceptible to aggravation.

Other ill side effects include the scarring or rapid aging of lung tissue due to particle inhalation. This can lead to a reduction in full lung function, which in turn can reduce the quality of life of those affected, as well as make them more vulnerable to further respiratory problems such as pneumonia, bronchitis and even aggravated forms of asthma attacks. Instances of lung cancer can make themselves more prominent, as well as damage to many different organ systems due to the ability of particulate matter such as black carbon, or soot, making its way deep into the lung tissue and entering the bloodstream, whereby it can cause damage to the liver, kidneys and even disrupt reproductive health.

What are the main types of pollutants found in the air in Siem Reap?

Even with the mass lockdowns imposed post 2020, Siem Reap still remains a popular place to visit amongst Cambodians, as well as expatriates living and working in the country. As such, there would still be a fair amount of vehicular emissions found in the atmosphere, although not to the same massive degree that full tourist season would bring.

The main pollutants coming from vehicles would be ones such as the aforementioned black carbon, which is also produced from factories, open burn sites and anywhere that has some form of combustion taking place. Other chemical contaminants include ones such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂), both of which are released in large volumes from engines, with nitrogen dioxide being the most prominent offender, as well as the sulfur dioxide adding to the occurrences of acid rain, which can have disastrous effects on the ecosystem as well as destroying the ancient bas reliefs and stone walls of Angkor Wat.

Other types of pollution would be the finely ground gravel, dirt and silica dust, with silica being a known carcinogen when inhaled. Construction sites also release other dangerous materials such as mercury, lead and microplastics.

Is it safe to visit Siem Reap because of air pollution?

Whilst there are certainly days, or months that see less than appreciable readings of PM2.5 in the air, it can be concluded that with preventative measures in hand, it would certainly be safe to visit the city. With much of its pollution being dust based, sufficient quality respirator masks would aid greatly in reducing harm from the ill effects of pollution. Using up to date air quality maps as available on the IQAir website, or on the AirVisual app, would go a long way in helping individuals to make informed decisions as to when the air on any given day is at its cleanest.