|星期二, 1月 12|
对敏感人群不健康 101 美国 AQI
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对敏感人群不健康 105 美国 AQI
|星期一, 1月 18|
对敏感人群不健康 131 美国 AQI
不健康 154 美国 AQI
|星期三, 1月 20|
对敏感人群不健康 111 美国 AQI
|星期四, 1月 21|
对敏感人群不健康 131 美国 AQI
|星期五, 1月 22|
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对敏感人群不健康 139 美国 AQI
|星期日, 1月 24|
不健康 168 美国 AQI
Peshawar is a city located in Pakistan, being the 6th largest in the country as well as having a settlement history dating back to 539 BCE or earlier. It also borders on Afghanistan, another country that has issues with its air quality and pollution levels in a similar manner to that of Pakistan.
Regarding the air quality levels in more modern times, Peshawar was observed coming in with a PM2.5 reading of 63.9 μg/m³, putting it directly into the ‘unhealthy’ ratings bracket, a grouping that as the name suggests is detrimental to those who breathe air of this quality.
To be classified as unhealthy requires a PM2.5 reading of anywhere between 55.5 to 150.4 μg/m³, and with its reading of 63.9 μg/m³ Peshawar was also placed into 6th place out of all cities ranked in Pakistan in 2019, coming in just behind Muridke and Lahore. It also ranked in at 37th place out of all cities worldwide.
This is an indicator that whilst Peshawar does not have the same catastrophic pollution levels that other cities in Pakistan do (with Gujranwala and Faisalabad coming in with yearly averages of 105.3 μg/m³ and 104.6 μg/m³ respectively), it still has a pertinent pollution issue that would be of major importance to its citizens, particularly demographics that are the most at risk, such as young children, expectant mothers, the elderly as well as the sick or the immunocompromised.
Observing the data taken over the course of 2019, the months that stood out with the highest readings of PM2.5 were present at the very end of the year, as well as seeing some elevated levels at the start of the year, although not as prominent as other cities in Pakistan, which often see their highest pollution numbers coming in at January (for example both Gujranwala and Lahore both saw their highest readings in January at 220.4 μg/m³ and 199.1 μg/m³ respectively.
PM2.5 refers to fine particulate matter that is 2.5 micrometers or less in diameter, making it approximately 3% the size of a human hair, and due to this size, of particular danger to respire, hence why it is used as a major component of calculating the overall levels of air quality.
Regarding its readings, as is common to Pakistan, the air quality started to decline in September, with August coming in at 41.4 μg/m³ and then jumping up fairly rapidly in September to 60.9 μg/m³, continuing upwards until December when its peak was reached at 113.5 μg/m³, making it the most polluted month of the year by far.
January also presented with some high readings, coming in at 81.2 μg/m³ before declining back down by nearly half to 44.3 μg/m³ in February. This is an indicator that inhabitants of Peshawar should take preventative measures towards the end of the year, with the wearing of particle filtering masks as well as avoiding outdoor activities during particularly bad spells of pollution being all the more important for those that wish to avoid the negative impacts that polluted air brings with it.
Peshawar sees numerous contributing sources of pollution, all of which can be compounded by factors such as geography and meteorological conditions, with the colder months of the year often having impacts on pollution levels due to the increased burning of materials for heat generation as well as the cold air trapping pollution within a city’s limits.
Main causes of air pollution in Peshawar would include emissions and fumes from vehicles, with numerous cars, motorbikes and rickshaws populating the roads, along with heavy duty vehicles such as trucks and lorries, many of which run on diesel fuels, or fuels of considerably lower quality than is seen on an international level, therefore putting out far more noxious chemicals.
Others include emissions from factories and other industrial sites, as well as from brick kilns, a pervasive problem the whole country sees, with unclean materials often used to fire these kilns, thus giving off large amounts of smoke and fine particulate matter. Other pertinent sources include the burning of crops, as well as other open burn sites focused on the disposal of garbage and other refuse. Poorly maintained roads and construction sites are also sources of large amounts of fine particulate matter. These would all be the compounding sources of pollution seen in Peshawar.
With sources of pollution such as vehicle and factory emissions being prominent contributors, the main types of pollutants arising from these would be ones such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), both of which are emitted in high volume by cars, with nitrogen dioxide being the most present in the atmosphere in any area that sees a high volume of traffic, often correlating directly to the point that nitrogen dioxide levels can be used to calculate how much pollution is actually being caused by pollution alone.
Other pollutants that arise from the burning of unclean fuel sources such as those seen in factories would be black carbon and volatile organic compounds (VOC’s), some examples of which would be benzene, formaldehyde, methylene chloride, tetrachloroethylene and toluene. They are known as being volatile due to their property of becoming a gas at low temperatures, hence easier to respire and of greater threat to human health.
When materials such as wood or synthetic items such as plastic or rubber are burnt at these open burn sites or rubbish heaps, they can release chemical compounds such as dioxins, furans, polychlorinated biphenyls as well as dangerous metals such as lead, mercury and cadmium. Brick kilns will also release the aforementioned black carbon, along with carbon monoxide (CO) and oxides of nitrogen (NOx), which can lead to the formation of nitrogen dioxide as well as ozone (O3).
Once again looking at the data from 2019, the months that displayed the cleanest levels of pollution were in the earlier portion of the year, excluding January, which came in with a very high reading. After that the PM2.5 readings dropped considerably, with the cleanest reading of the year being taken in March, with a PM2.5 reading of 28.6 μg/m³, making it the only month of the year to fall into the ‘moderate’ pollution bracket and a time when the air would be of less danger to its inhabitants, although of note is that any reading over the World Health Organizations target goal of 10 μg/m³ or less may have detrimental effects on health.