|星期二, 1月 19|
非常不健康 259 美国 AQI
|星期三, 1月 20|
非常不健康 287 美国 AQI
|星期四, 1月 21|
非常不健康 238 美国 AQI
不健康 191 美国 AQI
|星期六, 1月 23|
不健康 168 美国 AQI
|星期日, 1月 24|
不健康 174 美国 AQI
|星期一, 1月 25|
不健康 183 美国 AQI
|星期二, 1月 26|
不健康 185 美国 AQI
|星期三, 1月 27|
不健康 181 美国 AQI
Patna is the capital city of Bihar and is situated on the banks of the river Ganges in Eastern India. It is also very close to three other large river systems which not only make it make it unique but also the largest riverine city in the world. Towards the end of 2020 Patna experienced some extremely poor air quality with some days returning readings from the hazardous zone. The average PM2.5 measurement for 2019 was 82.1 µg/m³. Which was an improvement on the 2018 and 2017 figures which were 119.7 µg/m³ and 118.5 µg/m³ respectively. For just 2 months in 2019 Patna experienced “Moderate “air quality with figures in the low 30s. Four of the remaining months put it in the “Unhealthy” category with figures between 55.5 and 150 µg/m³. During November, December and January the air quality was recorded as being in the “Very unhealthy” bracket with figures of between 150.5 to 250.4 µg/m³. The remaining three months recorded levels put Patna in the “Unhealthy for sensitive groups” category. These quoted figures are a direct indication of the air quality index with figures recommended by the World Health Organisation (WHO).
In November 2019, Patna was declared to be the most polluted city in Bihar with PM2.5 levels reaching a staggering 428 µg/m³. The reason behind this sharp unexpected rise is that, due to floods, straw from Paddy fields is being burnt in nearby areas which adds particles to the fog that is already present there which formed because of the governments’ construction works being carried out in the city. The State Pollution Control Board has complained to the local authorities about the burning of garbage and stubble in the fields. Their answer was that this trend needs to be suspended immediately with the cooperation of the Department of Agriculture, otherwise the situation will worsen.
One of the more unusual reasons for the poor air quality is due to the river Ganges changing its course over the past two decades. Over this time, it has moved 4 kilometres away from the city, leaving large areas of dry sand which was once the river bed. This dry sand is picked up by the strong winds blowing in from the Himalayas and depositing it across the city.
This situation is compounded by a large amount of traffic on the roads which churn up the dust after it has settled and send it airborne once more. The mining of sand has been stopped but the transportation of it on open lorries continues unchecked.
The construction industry needs to be encouraged to shield the spread of dust into the environment and spray the ground with water to stop the dust rising up. These regulations are seldom adhered to for any notable length of time.
People still burn wood, coal and dried dung cakes as fuel both for cooking and for heating purposes in the cooler months. Dried leaves and other organic matter are often disposed of in this way. According to the website operated by the Bihar State Pollution Control Board (BSPCB) the AQI in Patna was 430 at noon on 27th November 2019 falling slightly to 427 at 3 pm and 425 at 4 pm. It had been 419 on 26th November and 404 on the day before. All of these figures classify it as “severe”. It fell slightly over the next 2 consecutive days to 395 and 398, but these figures are still classed as “Very Poor”. The board added that the figures were not as accurate as was thought because they all came from just one monitoring station. Four new ambient stations were added during the following month.
The local authorities intend to plant trees on the dried-up river bed to create a green zone. The land will be very fertile and trees should soon establish themselves as a green belt and stop the sand from blowing away. The board intend to plant up to 117 varieties of local trees from between 3 to 20 metres high, to help combat climate change. Unfortunately, due to the lack of funds, this project has yet to start.
The Central Pollution Control Board considers PM2.5 levels in the air to be a normal range from 60 to 90 µg/m³, but according to the World Health Organization (WHO) standard, the annual average of PM2.5 should not exceed 40 µg/m³ (micrograms per cubic meter). During the last year, for not a single day has the air of Patna and Muzaffarpur been recorded at the standard level of the World Health Organization.
Towards the end of 2020, measurements were taken from the monitoring stations which indicated that Patna was experiencing pollution levels classed as “Hazardous”. The figures are in excess of US AQI 300, getting as high as 369 on some days.
With pollution at these levels, the general advice is to stay at home and close all doors and windows to prevent the dirty air from entering and avoid any outdoor activity, if possible. If a trip outside is unavoidable then it is advisable to wear a good quality mask and limit the time spent away from home.
Even people who are healthy can suffer health effects from exposure to polluted air. This will vary from person to person and it depends on many factors such as the type of pollutant and its concentration level, your current state of health and the length of time exposed to the dirty air.
High levels of pollution cause respiratory illnesses and put extra stress on the heart and lungs. Cells can become irreparably damaged, too. The ageing of the lungs accelerates as they must work harder to get the level of oxygen that the body needs. Diseases such as asthma, bronchitis, emphysema and even cancer can be attributed to exposure to polluted air.
The most susceptible groups of people are those with existing medical problems, pregnant women, children under the age of 14 years and senior citizens.