Air quality in Hanoi during the week ended November 23 at many automatic monitoring stations significantly improved thanks to the existence of rain and wind, according to the Agency of Environmental Protection (EAP).

Air quality index (AQI) at the monitoring stations. Data: AEP

The agency said that Hanoi’s air quality index (AQI) measured at 10 monitoring stations in the city ranged from 36 to 199 during the week.

At monitoring stations such as Trung Yen 3, Kim Lien, Tan Mai, My Dinh and Tay Mo, in the past week, the AQI was better than the previous week. In particular, there was one day (November 19), the AQI the five stations was at the good level (green) and at the average level (yellow), accounting for 14.3%.

Kim Lien station had the best AQI that had no day hitting at the bad level, with reading in 28.6% of the week days at the average.

Meanwhile, at two stations of Tan Mai and Tay Mo, although there was no day at the very bad level, 42.9% of the days were at the bad level, the rest were at the average level.

Percentage of days with air quality at different levels. Data: AEP

At two traffic monitoring points in Minh Khai and Pham Van Dong wards, which usually see heavy traffic, the AQI in the week also saw improvements, with three days at the average level.

However, Pham Van Dong station also had 42.9% of the days with the AQI at the very bad level, the remaining were at the bad level while Minh Khai station recorded 57.1% and 0%, respectively.

The highest readings at Minh Khai and Pham Van Dong stations were 199 and 192, respectively.

At monitoring stations such as Hoan Kiem, Hang Dau and Thanh Cong, this week's AQI was better. For instances, Hoan Kiem station had four days at the average level (57.1%), two days at the very bad level (28.6%) and one day at the very bad level (14.3%).

It can be seen that air quality and weather conditions during the week are closely correlated. The large difference in day and night temperature was detrimental to the diffusion of pollutants in the air, leading to the AQI hitting the bad level at some locations, which adversely affected local residents’ health.

The EAP recommended that Hanoi’s residents should follow air quality information where they are living and working before going out to prevent diseases.