|星期五, 4月 9|
对敏感人群不健康 105 美国 AQI
|星期六, 4月 10|
对敏感人群不健康 115 美国 AQI
|星期日, 4月 11|
对敏感人群不健康 130 美国 AQI
|星期一, 4月 12|
中等 99 美国 AQI
对敏感人群不健康 122 美国 AQI
|星期三, 4月 14|
对敏感人群不健康 125 美国 AQI
|星期四, 4月 15|
对敏感人群不健康 120 美国 AQI
|星期五, 4月 16|
对敏感人群不健康 113 美国 AQI
|星期六, 4月 17|
对敏感人群不健康 130 美国 AQI
|星期日, 4月 18|
对敏感人群不健康 125 美国 AQI
Ludhiana is a city located in the Indian state of Punjab, being one of the largest cities in the state and a heavily industrialized hub of northern India, often referred to as ‘the Manchester of India’ by the BBC, pertaining the massive industrialization that Manchester in the United Kingdom underwent during the previous century.
Looking at the pollution readings taken over the course of 2019, one can see that Ludhiana came in with a yearly PM2.5 average of 49.3 μg/m³, a somewhat high reading that put it into the ‘unhealthy for sensitive groups’ bracket, a grouping that requires a PM2.5 reading of anywhere between 35.5 to 55.4 μg/m³ to be classified as such. As the name implies, this level of air quality can cause a large amount of problems for certain demographics of the population, with groups such as young children, the elderly, the immunocompromised or any ill people with preexisting health conditions being most at risk. Pregnant women are also particularly vulnerable due to the effect that pollution can have on unborn babies.
Ludhiana's reading of 49.3 μg/m³ put it into 127th place out of all cities ranked worldwide in 2019, a poor placing showing that the air would be permeated with smog, haze and smoke for most of the year, with many months of the year showing even higher readings, and no periods of respite (as is seen in some polluted cities, often they will have a few months of cleaner air quality due to changes in human activity or the weather).
Ludhiana also came in at 44th place out of all cities ranked in India, and considering that India itself ranked 5th place out of all countries worldwide in 2019, is even further proof that Ludhiana is suffering from some pollution related issues and poor air quality.
Looking at the multiple sources of where pollution seems to arise from in the city, there are several that stand out as being the most prominent, whilst others are contributing factors that whilst not as pollutive, still contribute to the year round ambient pollution readings.
One of the main sources of pollution is that of vehicle emissions, and with some 1.6 million people living there (from a census taken in 2011, most likely not indicative of how much the population has grown since then) would be that of vehicle emissions, with hundreds of thousands of vehicles populating the roads, often running on poorer quality fuels, as well as diesel fuels, both of which put out far more pollution than their cleaner or non fossil fuel counterparts would.
Heavy duty vehicles such as lorries and trucks would be ferrying large amounts of industrial materials and goods in and out of the city, due to it being an industrial hub. Following on from this, large amounts of pollution, if not equal to or more than that of vehicle fumes, would be released into the atmosphere from the countless factories dotted around the city’s limits.
Many of these factories would lack the more stringent international pollution regulations that help to keep certain chemical outputs to a minimum. In closing, vehicles and factories are the main causes of pollution.
Other ones of note would be the open burning of trash and refuse material, both organic and synthetic, as well as the burning of charcoal and wood for cooking in poorer districts. Many construction sites and road repairs would also contribute heavily to the amounts of fine particulate matter in the air, bringing both the PM2.5 and PM10 levels up considerably.
Observing the data taken over the various months of 2019, there starts to emerge a clear time frame when the pollution levels are significantly elevated, although even the cleaner times of the year still held fairly poor levels of air quality.
The months that came in with the worst readings of pollution were towards the very end of the year, with the months of October through to December having the highest readings of PM2.5. PM2.5 refers to fine particulate matter that is 2.5 micrometers or less in diameter, sometimes going down to sizes as small as 0.001 microns across, and due to these properties, they are of great danger to human health when respired. As such they are used as a major component of air pollution calculation.
Looking back at the most polluted months, October through to December all came in with PM2.5 readings of 69.9 μg/m³, 78.8 μg/m³ and 62.4 μg/m³ respectively, before declining back to less hazardous (but still unsafe) levels of pollution in the earlier portions of the year.
These readings put all three months into the ‘unhealthy’ ratings bracket (55.5 to 150.4 μg/m³ required for classification), with November being the most polluted month of the year with a rather large reading of 78.8 μg/m³.
Following on directly from the previous question, whilst the end of the year had the worst readings of pollution, the times of the year that had the lowest levels of PM2.5 in the air were February, and then August to September.
These are somewhat sporadic and follow no particular pattern, especially with February being surrounded by other highly polluted months. Their PM2.5 readings in order were 23.1 μg/m³, 29.1 μg/m³ and 35.2 μg/m³, making February the cleanest month in 2019, and as mentioned an abnormality as all the months it was surrounded by came in with PM2.5 readings of double Februarys number.
With a large amount of pollution coming from industrial and vehicular sources, the pollutants would be associated largely with the combustion of fossil fuels, as well as a certain degree of industrial effluence. Toxic metals such as mercury, lead and cadmium can be found around many industrial areas, with other contaminants such as polycyclic aromatic hydrocarbons, black carbon (released from any combustion source) as well as volatile organic compounds (VOC's).
Some examples of VOC's would include benzene, methylene chloride, xylene and formaldehyde. These are particularly dangerous due to them being in a gaseous state at lower temperatures, due to their volatile nature.
Pollutants released from vehicles would be the ever present nitrogen dioxide (NO2) and sulfur dioxide (SO2), with nitrogen dioxide being the most prominent over areas that see high volumes of traffic. Finely ground gravel, soil and silica dust would also make up a large amount of additional particulate matters, with silica dust being a known carcinogen, along with the aforementioned black carbon. These are but a few of the pollutants that would be found in the air in Ludhiana.