尼泊尔的空气质量

How polluted is Nepal?

Nepal is a landlocked country located in south Asia. It has a wide array of different geographical terrain within it, with large amounts of beautiful and pristine mountain ranges and valleys. Whilst these areas lend themselves to creating a wonderful image of Nepal, its geographical features also assist in the elevation of its already high pollution readings. It finds itself situated directly in between India and China, two economic giants in their own right as well as being the world’s top contributors to air pollution.

Bangladesh is also located within 30km from its southeastern region, another country that suffers from heightened pollution levels. additionally, the numerous mountain ranges and valleys create pollution sinks for cities such as Kathmandu, the capital city and economic heart of Nepal. Within these pollution sinks are areas where large amounts of dust, vehicular fumes and other smoke sources can gather, and due to them coalescing within the city limits which are surrounded by valleys and mountain ranges, they often accumulate over long periods of time due to lack of strong winds and other meteorological effects that would assist in the removal of built up pollution in the air.

In terms of its PM2.5 levels, Nepal came in over 2019 with a reading of 44.46 μg/m³. This number puts it into the ‘unhealthy for sensitive groups’ bracket, which as the name implies, the air has potential health issues for those that are sensitive to pollution, including young children, the elderly, those with respiratory conditions as well as pregnant mothers.

The unhealthy for sensitive groups rating requires a PM2.5 reading of anywhere between 35.5 to 55.4 μg/m³ to be classed as such. This puts Nepal's reading right into the middle of this group, as well as making it the 8^th most polluted country worldwide in 2019, coming in just behind other countries such as Bahrain (46.80 μg/m³) and Indonesia (51.71 μg/m³).

This 8^th place position is not an ideal spot for Nepal to find itself in, in regards to the quality of its air and the safety of its citizens, as well as the plethora of tourists that make their way into Nepal each year, although of note that during the year of 2020, due to covid-19 these tourist numbers were drastically reduced, having some negative effects of Nepal's overall economy.

Kathmandu also came in with a similar number over the year of 2019, with a PM2.5 reading of 48 μg/m³. This means it was also placed into the unhealthy for sensitive groups bracket, with some of its months seeing huge spikes in pollution levels, subject to high levels of smoke, haze, dust and other noxious fumes.

So, in finishing, whilst Nepal has many areas that would see crystal clear air quality, particular in the numerous mountain towns and villages across the country, it stands to reason that the more populated areas are indeed suffering from some high levels of pollution.

What are the main causes of pollution in Nepal?

There are numerous causes of pollution across the country, many of which stem from a lack of regulations regarding operations such as factories and construction sites, open burning as well as the fuels used in the many vehicles found in Kathmandu and other cities. To address the issue of vehicles first, it can be seen that many of the numerous motorbikes, cars and buses are quite aged and deteriorated, yet due to an ingrained ingenuity to keep old things alive and running, many of them are still moving up and down the country despite having engines that put of vast amounts of black soot and other toxic pollutants that arise from poorly combusted fossil fuels, in particular diesel. This finds no regulation amongst its use, or indeed in Nepal's particular case, massive overuse.

Another element that has contributed to the levels of polluted was the catastrophic 7.8 magnitude earthquake that occurred in 2015, levelling many historic areas and domiciles across the capital city, leading to a massive spike in dust pollution, much of which still remains till this day due to the lack of proper cleanup conducted by the country. Many of the affected areas still lie in ruins due to Nepal not having the infrastructure needed to repair such massive amounts of damage.

As a result, the previously mentioned dust finds itself in every corner of the capital, permeating the roads where it is ground up into even more fine particulate matter and sent billowing into the atmosphere. This creates larger readings of PM2.5 and PM10 in the air, which can have highly damaging effects when respired, as well as mixing with other chemicals from exhaust fumes and factory emissions to create even more harmful compounds and other forms of material.

Open burning of refuse and waste is another highly pertinent issue, with the country of Nepal acknowledging that cracking down on this could occur quite easily with little resources or time being put into it, but as it stands it has yet to be enforced. Due to a lack of proper garbage collection and disposal infrastructure, large amounts of the population, both in the capital and in other cities as well as rural areas, take to lighting their refuse on fire in order to get rid of it.

These piles contain everything from wood or other similar dead organic materials, to highly toxic manmade materials such as rubber, plastics and even metals. These contribute massively to pollution levels across the country, with burning also becoming an even more salient point during the winter months, when large amounts of wood and coal are burnt for the warming of homes, as well as being burnt year-round for cooking and other such small-scale local practices. However much of a small scale they are though, they eventually add up to disastrous levels when practiced by large amounts of the population, causing far worse readings of US AQI as well as heightened PM2.5 and PM10 levels, the effects of which will be discussed in short.

What are the health effects of breathing polluted air in Nepal?

When observing some of the more polluted months caught on record in Nepal, certain ones such as January 2019 in Kathmandu stand out. This month came in with a PM2.5 reading of 102.7 μg/m³, putting it into the higher end of the ‘unhealthy’ ratings bracket, which requires a reading of anywhere from 55.5 to 150.4 μg/m³ to be classed as such. This is an extremely high rating of pollution, and when health effects are concerned on the general population, the higher the levels of pollution that are present, the more likely that these health effects will occur.

When examining PM2.5, it is described as particulate matter that is 2.5 micrometers or less in diameter. Due to its incredibly small size, it has a whole host of highly negative effects when inhaled (which is why it is used as such an important component in calculating the overall levels of pollution levels, or air quality index).

When inhaled, these small particulate matters such as black carbon or finely ground gravel or silica dust, can cause scarring to the lung tissues that lead to an overall reduction in full lung function. Material with carcinogenic properties can penetrate deep into the lungs and accumulate, leading to heightened instances of cancer. These tiny particles can also cross over into the bloodstream via the air sacs in the lungs, wreaking havoc on an individual’s health by causing damage to blood vessels as well as organs such as the liver and kidneys (along with affecting reproductive health).

Further conditions can include ones such as ischemic heart disease, arising from when inadequate amounts of oxygen reach the heart tissues, leading to a deterioration in function. Further heart complications can include arrythmias, increased instances of heart attacks and problems related to blood pressure regulation.

These are to name but a few of the health issues of being exposed to high levels of smoke and haze-based pollution. The plastic and other synthetic materials being burnt in the open fires can cause irritation to the nose, eyes, mouth and airways, as well as causing irreversible changes to the nervous system that can lead to chronic fatigue, cognitive impairments and headaches, all of which have a salient effect on a young and growing population.

Babies that are exposed whilst in the womb have an increased chance of miscarriage, or being born prematurely or with a low birth weight, thus heightened pollution levels lead directly to higher rates of infant mortality, as well as large amounts of the population having their lives cut short due to health problems stemming from air pollution.

When is pollution at its worst In Nepal?

The levels of pollution in Nepal correlate heavily with changes in weather, with the colder and drier months seeing the absolute worst levels of pollution across all the registered cities, whilst the monsoon season brings with it some respite in terms of pollutants found in the air, due to the rains highly prominent effect of washing chemicals and dust out of the air, as well as washing away accumulations that have gathered on the ground across the city.

Observing the data taking over 2019 across all cities, it is apparent that pollution levels start to rise just as the monsoon season comes to an end, which happens to fall on October. A marked increase in PM2.5 readings are seen across the four cities, whilst in contrast September’s readings often come in remarkably cleaner. To look at some of these statistics, Kathmandu came in with a reading of 11.8 μg/m³ in August, its cleanest reading out of the entire year. This was followed in September by a reading of 13.1 μg/m³, a slight increase that was enough to put it up by a ranking, but at the absolute lowest end of the ‘unhealthy for sensitive groups’ bracket.

Patan, the second most polluted city in Nepal, came in with a PM2.5 reading of 7.1 μg/m³ in September 2019, making it fall nicely within the World Health Organizations (WHO’s) target goal for great air quality of 0 to 10 μg/m³, demonstrating that Patan had an extremely good quality of air over September. Other cities with similar readings were Kirtipur with a reading of 6 μg/m³ in August and 6.4 μg/m³ in September.

Now in contrast to the next month, Kathmandu's October reading came in at 30.6 μg/m³, a number nearly three times that of the previous month. The same occurred in Patan, with its 7.1 μg/m³ jumping up to 22.3 μg/m³ in October, and once again a similar story in kirtipur, with its reading of 6.4 jumping to 12.4 μg/m³, almost double of the previous month. This is statistical proof that Nepal begins its AQI decline towards the end of the year, with peaks in pollution levels occurring in December through to January. To summarize, the months that are the cleanest in regards to air quality in Nepal are July through to September, and the dirtiest months are November, December and January, times when preventative measures such as wearing of particle filtering masks and avoiding outdoor activities if possible, become of increased importance.

Of note is that Kathmandu, due to being the capital city, saw elevated readings of PM2.5 well into May, before dropping rapidly in June. For those wishing to travel to Nepal, as well as its inhabitants already living there, these are all important factors to take into consideration, although due to the monsoon season, large increases in waterborne illnesses also become prominent, something of note for people that have Nepal as a destination.

Is the quality of air in Nepal improving?

Looking at the air quality data over the last few years, it appears that Nepal made a marked improvement from 2018 to 2019, with a PM2.5 reading of 54.15 μg/m³ being recorded as an average over 2018 as compared to 44.46 μg/m³ in 2019. Whilst this shows an improvement over the course of one year, when observing data taken from the capital city, Kathmandu, it also shows a similar trend of worse air quality in 2018 being improved upon in more recent times. However, when the data from 2017 in Kathmandu is observed, a reading of 45.9 μg/m³ was recorded, which is a better number than the one that was taken in 2019.

This gives a level of uncertainty as to whether pollution levels in Nepal are improving, or just fluctuating between similar levels of pollution. It will take many improved initiatives in the coming years, such as the cracking down on open burning fires, as well as the gradual removal and phasing out of diesel fuels and the ancient vehicles populating the roads. Facing massive economic growth, Nepal will be in a position where its pollution levels may have a long way to go before improving, so as it stands for now, the differences between numbers of PM2.5 are hard to differentiate between being actual improvements or just the aforementioned fluctuations in numbers. With the implantation of the cleanup initiatives, Nepal may yet see improved levels of US AQI as well as lower PM2.5 readings in a hopeful future.