|优秀|| 12 美国 AQI||PM2.5|
|PM2.5|| 3 µg/m³|
|pm10|| 6 µg/m³|
|Open your windows to bring clean, fresh air indoors|
|Enjoy outdoor activities|
|星期四, 4月 8|
优秀 20 美国 AQI
|星期五, 4月 9|
优秀 25 美国 AQI
|星期日, 4月 11|
优秀 8 美国 AQI
优秀 8 美国 AQI
|星期二, 4月 13|
优秀 20 美国 AQI
|星期三, 4月 14|
优秀 25 美国 AQI
|星期四, 4月 15|
优秀 20 美国 AQI
|星期五, 4月 16|
优秀 14 美国 AQI
|星期六, 4月 17|
优秀 17 美国 AQI
|星期日, 4月 18|
优秀 17 美国 AQI
Bern is a city in Switzerland, holding the title of the de facto capital, or as it is known locally, the ‘federal city’, a title that is common in countries such as Russia, the United States and Germany. It is the 5th most populous city in Switzerland, being home to some 144 thousand inhabitants. It is a city with a high employment rate, with a multitude of industries ranging from construction to manufacturing, as well as a relatively large concentration of distinguished fields such as technicians or scientists. With these factors in mind, there would be a large amount of air pollution coming from the mass movement of people in their daily commutes to work, with vehicles being one of the more problematic causes of air quality reduction in Bern, as well as Switzerland as a whole.
In 2019, Bern came in with a PM2.5 reading of 10.9 μg/m³, putting it in the ‘good’ ratings bracket, a respectable group to be in which requires a PM2.5 number of anywhere between 10 to 12 μg/m³ to be classified as such. Of note is that it is only 0.9 units away from being moved down into the best air quality group, that of the World Health Organizations (WHO's) target goal of 10 μg/m³ or less, with the closer to 0 being of course the most optimal to achieve.
This reading of 10.9 μg/m³ placed Bern in 7th place out of all cities ranked in Switzerland and 2235th place out of all cities ranked worldwide. This is indicative that Bern does indeed have a good quality of air, albeit with several months that rise in their pollution levels, meaning that there is some room for improvement.
As mentioned before, whilst Bern has a good overall quality of air, with many months coming in with respectable readings (which will be covered in greater detail in short), there are several months where the air quality drops to less than appreciable levels, indicating that certain portions of the population may be at risk, with the elderly, young children as well as the immunocompromised or those with preexisting conditions being the most vulnerable.
Some health issues may include irritation to the mucous membranes, particularly the eyes, nose, throat as well as the skin, with people who live in high pollution areas such as near rush hour traffic jams or busy road intersections being at particular risk (with chemical pollutants such as nitrogen dioxide (NO2) having the ability to cause aggravated asthma attacks as well as rapid aging and damage to the lung tissue).
Other conditions may include a host of respiratory ailments, with pneumonia, bronchitis and emphysema all being on the list of both chronic and acute pulmonary conditions. Increased rates of cancer also correlate with higher pollution, and as such it has become of the utmost importance for people to protect themselves from pollution exposure.
Observing the data taken over the course of 2019 as a good indicator of average pollution readings, it becomes apparent that there is a consistent pattern as to when the air quality levels start to drop and when they improve. According to the monthly data, it is the winter period that sees the worst levels of pollution, due to a large increase in heating use from both homes and businesses, as well as an increase in the burning of wood and charcoal in more traditional homes that still utilize such heating methods, despite them being somewhat cracked down on.
Looking at the numbers, the air quality shows a distinct decline in November, with a PM2.5 reading of 11.6 μg/m³ following on from the previous months reading of 8.2 μg/m³. This then continues upwards to 14.7 μg/m³ in January, and then onto a yearly high of 18 μg/m³ in February, making it the most polluted month out of the entire year.
Of note is that in Bern, and indeed every other city in Switzerland, there is a sudden drop in pollution in the month of March, with a reading of 9.6 μg/m³ being taken at that time. This is followed by one final spike of PM2.5 (across all cities), with a reading of 13.8 μg/m³ taken in April, after which the air quality levels return to more respectable numbers as the warmer months start to take effect.
In closing, the months of November through to April of the following year are when pollution levels are at their very worst, with months of January, February and April all having the highest readings, coming in with ‘moderate’ air quality readings, which requires a PM2.5 number of anywhere between 12.1 to 35.4 μg/m³ to be classified as such.
With much of its pollution coming from the use of vehicles, and with other sources such as factories and industrial areas putting out their own forms of pollution (although with significantly more stringent emission caps on them when compared to other countries), it stands to reason that much of the contaminants and chemicals, as well as the fine particulate matter in the air would be related to these sources.
As mentioned before, cars put out large amount nitrogen dioxide, as well as sulfur dioxide (SO2) into the atmosphere, and personal vehicles as well as heavy duty ones such as trucks, lorries and buses will occasionally be running on diesel, a fossil fuel that releases its own novel pollutants when subject to use in motors.
These pollutants would include black carbon, mainly in the form of soot, as well as volatile organic compounds (VOC's), both of which are produced from the incomplete combustion of fossil fuels as well as organic matter, and as such would find their creation from both vehicles as well as the previously mentioned burning of wood and charcoal in certain homes during the winter months. Some examples of VOC's are chemicals such as benzene, toluene, xylene, methylene chloride and formaldehyde.
In contrast to the prior question, the times of the year when Bern sees its best levels of pollution begin in May, and run all the way through to October, before the air quality starts to see its decline again in September. This means that for six months, or half of the year, Bern has air quality that successively falls within the WHO's target goal, with September being the cleanest month out of the entire year of 2019 with a PM2.5 reading of 7.9 μg/m³.