塔什干的空气质量

Is Tashkent a city with good air quality?

Tashkent is the capital city of Uzbekistan, also holding the title of the largest city in the country. It has a long recorded history of many different cultural influences, ranging from Turkic through to the ancient Persians, and in more modern times that of Russian influence, although not as prominent as it once was due to the collapse of the Soviet Union, and Tashkent’s subsequent return to sovereignty. It has over 2,200 years of recorded history, counting it as one of the more ancient cities to still be in existence, having been a prominent city that benefited from trade taking place across the silk road in times past.

Nowadays, it is a city that is going through a steady economic growth, with industrial facilities cropping up alongside a growing population (which is currently sitting at 2.57 million people as of 2020). In regards to its air quality, as with many cities in the region, it suffers from some pollutive issues due to overuse of fossil fuels as well as maintenance of poor environmental practices such as using poor or lower quality fuels as well as burning large amounts of both organic and synthetic materials, combined with the heavy dust storms that occur across that particular part of the world.

In 2019, Tashkent came in with a yearly PM2.5 average reading of 41.2 μg/m³, a high reading that placed it into the ‘unhealthy for sensitive groups’ bracket, which requires a PM2.5 reading of anywhere between 35.5 to 55.4 μg/m³ to be classed as such. This reading also placed it into 219^th place out of all cities ranked worldwide, an extremely high ranking that is indicative of fairly severe pollution problems.

What are some of the main causes of pollution in Tashkent?

With such a high reading of PM2.5 taken over the year of 2019, there would be many different sources of pollution coming together to get the heavily compounded numbers that were recorded, with the country having its own unique source of pollution adding to the already high levels seen (located far from Tashkent, to the far northwest near the Aral Sea).

Massive overuse of automobiles amongst the city’s population contributes significantly to the pollution levels, with many of these vehicles being aged and some even being leftovers from the Soviet Union, running on ancient motors that put out far more oil vapors, particulate matter and noxious chemical fumes into the air than a more modern cleaner counterpart would.

Other causes of pollution in Tashkent would be fumes from factories, power plants and other industrial areas. The burning of coal and other materials is responsible for the large output of smoke, haze and other hazardous materials that can be found in the air throughout Tashkent, as well as the rest of the country. These chemical pollutants will be discussed at greater length in following.

What are some negative health issues associated with pollution in Tashkent?

With PM2.5 readings going as high as 75.5 μg/m³ during certain months of the year, there would be a significant amount of health issues associated with breathing the air during such a time, and indeed throughout much of the year, with any PM2.5 reading over the World Health Organizations (WHO's) target goal of 10 μg/m³ or less having the ability to cause a whole host of negative health ailments.

Some of these would include short term or acute issues such as irritation to the mucous membranes, with the eyes, nose, ears and mouth all being affected, as well as the skin being prone to breakouts, especially amongst those with sensitivity to chemical pollutants. Long term and chronic issues would be ones such as elevated risks of cancer, particularly regarding the lungs but also of the throat, stomach and other organs of the body, due to the pervasive nature of particulate matter and its ability to enter the blood stream via the lungs. Others would be respiratory ailments such as pneumonia, bronchitis, emphysema and aggravated asthma attacks, as well as scarring of the lung tissue and a subsequent reduction in its full function.

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

Some of the main pollutants found in the air in Tashkent would be ones such as black carbon and volatile organic compounds (VOC's), both of which are released from the incomplete combustion of fossil fuels, as well as from organic material such as wood. Black carbon is the main component in soot, and is released from all combustion sources, emanating from vehicles, factories as well as the burning of wood for heating or cooking in certain homes (more common during the winter months as well as in lower income districts where traditional practices are still used).

Some examples of VOC's would include chemicals such as benzene, toluene, xylene, methylene chloride and formaldehyde. Other pollutants released from sources such as vehicles would be ones such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂), with nitrogen dioxide being one of the main pollutants emitted from vehicles, as well as sulfur dioxide being a contributor to incidences of acid rain. Other pollutants released from combustion sites would be carbon monoxide (CO) as well as ozone (O₃).

When are the pollution levels at their worst in Tashkent?

Observing the pollution levels recorded over the course of 2019, Tashkent showed a distinct period of the year when the PM2.5 readings were significantly higher than other time periods. It appears that from the month of June through till December at years end, the pollution levels are at their worst, with some readings coming in many times higher than the lowest readings earlier in the year. April came in with a PM2.5 reading of 19.9 μg/m³, making it the cleanest month of the year. Although data is missing from the month of May, June showed a prominent leap in pollution levels, with a PM2.5 reading of 36 μg/m³.

From this month onwards, the readings continued to stay high, with increments also being shown. July through to December came in with readings of 48.7 μg/m³, 47.3 μg/m³, 44.8 μg/m³, 40.7 μg/m³, 75.5 μg/m³ and 39.1 μg/m³ respectively.

This made November the most polluted month of the entire year, falling into the ‘unhealthy’ ratings category, which requires a PM2.5 reading of anywhere between 55.5 to 150.4 μg/m³ for classification. As the name indicates, the air during this time period is extremely detrimental to those exposed, and in closing, the months of June through to December are when the levels of smoke, haze and pollution in the air would be at their worst.