Qualité de l’air à Dhankuta

What is the level of air pollution in Dhankuta now?

Dhankuta is a hill town and the headquarters of the Koshi Zone located in the Dhankuta District of Eastern Nepal. According to a 2011 Nepal census, the population was estimated to be approximately 26,500 inhabitants.

Towards the middle of 2021, Dhankuta was going through a period of “Moderate” quality air with a US AQI reading of 82. This United States Air Quality Index number is recognised worldwide and is endorsed by the World Health Organisation (WHO). It is extensively used when comparing cities’ air quality in different parts of the world because they use the same metrics.

Normally, up to six of the most commonly found pollutants are used in the calculation, but if six are not available, then it can still be ascertained by using what information was available. The figure here is based on just two readings which were as follows: PM2.5 - 26.8 µg/m³ and PM10 - 33.6 µg/m³. With high levels such as these, it is strongly recommended to stay indoors and close all doors and windows to prevent more polluted air from entering the room.

Those with a sensitive disposition should refrain from venturing outside until the air quality improves. The table at the top of this page may help with that decision.

Is the level of air pollution in Dhankuta the same all year round?

Because air pollution is so volatile, it is easily altered by many variables, such as wind speed and direction and the strength and amount of sunshine hours.

Looking back at the figures which are available on the IQAir.com website it can clearly be seen that the best quality air was available during the month of August when the recorded figure classified it as being “Good” with a figure between 10 and 12 µg/m³. With the exception of this month, the next best quality was to be had from May until the end of November with figures between 12.1 and 35.4 µg/m³ which classed it as being “Moderate”. January, March and April saw a decline in quality as it slipped into the “Unhealthy for sensitive groups” classification with figures between 35.5 and 55.4 µg/m³. The remaining two months of the year of February and December saw the worst quality when it was “Unhealthy” with figures between 55.5 and 150.4 µg/m³.

There were no records kept before 2020 when the average annual recording was 33.1 µg/m³. This figure could be artificially lower due to the restrictions put into place because of the COVID-19 pandemic. At this time, many staff were furloughed and permitted to work from home meaning they no longer needed to commute into the city on a daily basis. Factories had also been instructed to stop production. The closure of the factories also meant they were no longer polluting the air, albeit on a temporary basis.

What are the sources of Dhankuta’s polluted air?

The main source of air pollution in Dhankuta is an accumulation of smoke and dust particles. Other reasons are linked to the behaviour of burning garbage in public, not servicing vehicles regularly, uncovering construction work and running businesses with unregulated technology.

Forest fires have been set up in a controlled manner in many places in the belief that good grass will come afterwards.

Another major source is that of motor vehicles which are growing at an annual rate of 135 per cent, more than three times the population growth rate.

Nearly all commodities used in Nepal are imported from other countries so it all has to be transported from its Nepalese source to its ultimate destination.

The air quality is often worse during the colder winter months when temperature inversion traps the dirty air at ground-level. At this time of year, a lot of pollution is blown in from over the border from India due to their crop residue burning.

What can be done to lower the level of pollution in Dhankuta?

There are five main suggestions put forward to reduce pollution caused by traffic.

• Shifting to low carbon public transport is an important means to improve air quality.
• Enforcement of emissions standards that address sulphur content in gasoline and diesel can reduce particulate matter emissions.
• Converting three-wheel transit from gasoline to electric power is a useful strategy to reduce exhaust fumes from vehicles.
• Improving passenger comfort on public transport encourages its use.

In Nepal, a Cabinet decision last year adopted the Department of Environment’s guidelines for air pollution to declare a health emergency if AQI exceeded 300 – meaning the government can ban open burning, close factories, and take measures to reduce vehicles on the roads.

What are the effects of this polluted air on the human body?

The main cause of air pollution in Nepal is the fine particles in the air. Once these particles enter the human body through the respiratory system, they can damage various sensitive organs and systems, including the lungs and heart. Moreover, due to the carcinogenic elements in diesel vehicle smoke, they can even cause cancer. Pollutants from diesel usually contain finer particles than PM2.5, so these particles can float in the air for a long time and reach the human body. With the construction of physical infrastructure including roads, the dust has also increased in the last few years and its amount is more than PM10, which has caused many problems in human health. Not being aware of this issue now not only endangers human life, it can be fatal.

Long-term exposure to air pollution can cause many of the health conditions associated with increased vulnerability to Covid-19, such as diabetes and chronic heart and lung diseases. The air pollution emergency in Kathmandu puts the elderly, those with asthma and other respiratory ailments at high risk, and would be especially dangerous to those with Covid-19.

A report says that 100 per cent of the population in India lives in areas where PM2.5 levels are higher than the WHO Air Quality Guideline. Nepal is not far behind with 98 per cent of its people living in such areas. Exposure to air pollution has been shown to affect the human body’s immune defence, making an individual more susceptible to respiratory infections such as pneumonia and COVID-19.