Qualité de l’air à Patan

Does Patan have a high level of air pollution?

Patan is a city located in the south-central side of Kathmandu valley, being counted as one of the new metropolitan cities of Nepal (although having already existed for thousands of years). It also goes by the name of Lalitpur, having been known as Patan more historically but with interchangeable references. It is the third largest city in the country after Kathmandu and Pokhara, and besides being well known for its high amount of culture, historical sites and arts and crafts, is also unfortunately subject to some rather poor levels of air quality, in the same vein as many of its neighboring cities.

Due to the earthquake that occurred in 2015, the city was among many to have extensive damage caused, and this still lingers today due to lack of proper clean-up protocols. This has led to huge accumulations of dust, finely ground sand and other materials that fall under the fine (PM2.5) or coarse (PM10) matter bracket. PM2.5 refers to particulate matter that is 2.5 micrometers or less in diameter, making it roughly 30% the size of a human hair. It also has the capacity to go down to sizes many microns smaller, and due to the large variety of materials it is comprised of (some of which have carcinogenic or other harmful properties), is of great detriment to the health of people who are subject to breathing it. It can also be released from a number of other sources that will be discussed in short, and along with US AQI, is used as an accurate measure of the air pollution within Patan, particularly when discussing yearly averages.

Looking at the level of US AQI on record in May of 2021, Patan came in with a reading of 112, placing it in the ‘unhealthy for sensitive groups’ rating bracket. As the name suggests, this would have some consequences for those that are in poor health, as well as other at-risk groups. These include people such as young children and babies, as well as the elderly. The first two are at risk due to them undergoing their formative years, and any disruption to the various organ systems of the body (respiratory or nervous system related) can cause many debilitating effects that may stay with them for the rest of their lives. The elderly, too, are very much susceptible to the ill effects that respiratory trauma may cause, with simple infections sometimes resulting in severe consequences.

Looking at the levels of US AQI on record in Patan, it can be seen that it consistently came in with readings ranging from 93 (higher end of the ‘moderate’ pollution ratings bracket) all the way up to 122. This would indicate that the air quality in Patan may cause issues for many people, and as such preventative measures such as the wearing of fine particle filtering masks or avoiding outdoor activity during spells of high pollution may become of greater importance. These pollution updates can be followed via the air quality map as available above on the IQAir website or via the AirVisual app.

Can breathing the air in Patan make you sick?

As mentioned in the previous question, with its levels of US AQI on record, it is shown that the air in Patan can indeed have some negative health consequences. Some further ailments or symptoms that may show up when individuals are exposed to higher levels of pollution are ones such as dry coughs, irritation to the skin and mucous membranes, as well as higher risk of chest infections and other respiratory related diseases.

Repeated inhalation of fine particulate matter (along with many chemical compounds typically released from combustion sources such as vehicle engines or the burning of waste and other material) can cause inflammation or scarring to the lung tissue. This can not only lead to reduced lung function and a lower quality of life, but can make one more susceptible to further conditions down the line. Many of these would fall under the chronic obstructive pulmonary disease (COPD) bracket, and include ailments such as pneumonia, bronchitis, emphysema and various aggravated forms of asthma.

At what time of the year is the air in Patan at its most polluted?

Observing the PM2.5 levels collected over the course of 2020 as an accurate measure of when the air quality levels were at their worst, it can be seen that there were very distinct periods of time in which the pollution levels shot up and showed some rather dangerous readings, indicating that not only would vulnerable groups of people be at risk, but even healthy young adults may succumb to some form of illness or disease as a result.

As can be seen on the 2020 readings, the air quality started to take a turn for the worst between September and October, with the last two months of the year having some of the highest levels of pollution. As well as this, the first two months of the year also had elevated readings of PM2.5.

Their respective readings from January and February, as well as November and December came in at 58.1 μg/m³, 63.5 μg/m³, 53.2 μg/m³ and 65 μg/m³. This made December the most polluted month of the year with its reading of 65 μg/m³, followed closely by February.

What are some of the main pollutants found in the air in Patan?

The main pollutants found within Patan would be ones such as finely ground gravel, sand and silica dust, coming from many sources such as construction sites, poorly paved roads and other activities that disturb large amounts of earth (with even cars contributing to this).

Other pollutants include ones such as black carbon and volatile organic compounds (VOCs), along with nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃). Some examples of these VOCs would be chemicals such as benzene, styrene, toluene and formaldehyde.

When does the pollution level see improvements in Patan?

Whilst there are some very high readings of air pollution present within Patan, there are also several months that came in with very good levels of air quality. The months of June through to August possessed these best readings, coming in with very appreciable numbers of 11.1 μg/m³, 9.5 μg/m³ and 4.5 μg/m³.

This placed June in the ‘good’ air quality ratings bracket (10 to 12 μg/m³ required), and the other two in the World Health Organizations (WHO's) target goal of 10 μg/m³ or less for the best quality of air. August had an exceptionally good quality of air with its monthly average of 4.5 μg/m³, indicating that the air would be at its freest from clouds of hazardous particles, smoke, fumes and other noxious air contaminants.