The Hanoitimes - At the air monitoring points in Hanoi`s urban areas, the air quality index is mainly poor and unhealthy.
Hanoi's ten areas have suffered bad air quality index (AQI) for the past week, according to the Environmental Protection Division under Hanoi Department of Natural Resources and Environment.
Hanoi’s AQI from January 20 to January 26 showed that air quality declined markedly, mainly at poor and unhealthy levels. The area around Minh Khai Street had the poorest air quality in the week.
Hanoi’s AQI last week ranged from 56 to 285.
Hanoi's air quality is close to the danger level. Photo: Kinhtedothi.vn
At the air monitoring points in urban areas, the air quality index is mainly poor and unhealthy. Only 14.3% of the days when the air is measured as fair in Trung Yen and Tay Mo areas; while in 28.6% of the time, the air quality in Tan Mai and My Dinh is fair. Trung Yen 3 has the highest AQI with 57.1%, Kim Lien has the lowest one with 14.3%, the remaining is at low level.
According to the AQI value conversion table, the AQI is good (0-50) and has no negative effect on health. The average level (51-100) means that sensitive groups (children, the elderly and those with respiratory diseases) should limit their outdoor activities. At the unhealthy level (101-200), sensitive groups are recommended to stay indoors. At the very unhealthy level (201-300), sensitive groups should avoid going out, others should limit outdoor activities. At the hazardous level (over 300), people are recommended to stay indoor.
Air quality observed at traffic monitoring stations in Minh Khai and Pham Van Dong streets also sees bad quality due to emissions from large number of vehicles. The worst AQI at these two stations is 276 and 263, respectively.
It can be seen that during this week, the weather is still dry and cold, the temperature and humidity are low, without sunny days, and there is mist in the early morning, less rain and light wind. It is the adverse meteorological conditions that make the pollutant not diffuses but accumulates in the gas layer near the ground.
Another cause is that the end of January is also on the end of the lunar year, the demand for traveling is high, so the number of vehicles on the roads tends to increase, the speed of transport means decreases, resulting in long time traffic jams.
Besides, construction works are also urgently completed, partly increasing the concentration of substances in the air, causing air quality to drop markedly.
The three above-mentioned factors make Hanoi’s AQI near the dangerous levels.