
From around 2:15am to 9:00am on February 2morning, the thick fog and low cloud cover limited visibility for pilots makingit unsafe for aircraft operations. Many flights were affected, forcing the NoiBai International Airport to activate a safety protocol.
To ensure safety, some flights had to divert their landings toother airports or postpone, flying in holding patterns to wait for betterweather.
There were about 37 flights unable to land at the Noi BaiInternational Airport, with 12 flights diverted to nearby airports. Also,during this time frame, to ensure flight safety, 54 flights scheduled to departfrom Noi Bai had to delay take-off to wait for better weather.
The phenomenon of dense fog typically occurs in Hanoi and northernprovinces of Vietnam around February and March. Units in the aviation industryare always ready with contingency plans under conditions of limited visibilityto ensure safe flight operations.
"The Noi Bai International Airport hopes for passengers'understanding and compliance with the operational instructions of aviationpersonnel to ensure security and order and flight safety for passengers,"emphasised the airport's leadership.
Due to the impact of dense fog and bad weather in the areas of theNoi Bai Airport, Tho Xuan Airport (Thanh Hoa), Vinh Airport (Nghe An), and PhuBai Airport (Hue), to ensure safe operations, Vietnam Airlines had to adjustthe departure times, delaying from two to six hours for flights to and fromthese airports in the early morning on February 2.
Specifically, the affected flights include 8 flights from Ho ChiMinh City to Vinh with flight numbers VN7000, VN7004, VN7006, VN7008, VN7012,VN7014, VN7016, and VN7264. Flight VN7278 from Ho Chi Minh City to Thanh Hoa,VN7540 from Ho Chi Minh City to Hue also experienced delayed departure times.
At the Noi Bai Airport, many domestic and international flightslanding here had to circle or land at alternative airports in Hai Phong or Da Nang,waiting for better weather conditions to meet operational requirements.Departing flights from Noi Bai also had to delay their operational times toensure safety.
"Nearly 30 other domestic and international flights wereaffected in the queue, changing their schedules," said a representative ofVietnam Airlines.
Earlier on the night and early morning of Thursday, also due tothe impact of dense fog at the Tho Xuan and Vinh airports, four flights from HoChi Minh City to these locations were also delayed, from one to nearly fivehours.
"Rainy and foggy weather conditions may occur at airports inthe northern and central regions in the coming days. Passengers with travelneeds to provinces and cities in the northern region during this period shouldregularly monitor schedule information and weather conditions," advisedVietnam Airlines.
Fog hinders daily life
The fog in Hanoi also accompanied bad PM2.5 levels throughout thecity. Central districts such as Dong Da and Ba Dinh registered figures ofaround 260, while suburbs such as Nam Tu Liem and Cau Giay are around 230, allof which are at "very unhealthy" levels.
People commuting on February 2 morning also faced difficulties, asthe strange fog restricted vision.
In winter, Hanoi and the northern provinces experience reducedground heat from the sun, causing rapid cooling of the ground during the nightand early morning. This cooling phenomenon leads to temperature inversion,where the air near the ground becomes colder than the air above, creatingstable stratification that restricts the upward movement of heavier air.
Fog occurs when water vapour condenses into tiny droplets in theair near the ground, reducing horizontal visibility to less than 1km. Typicallyappearing white, fog can sometimes have a yellow or greyish colour. It oftenoccurs in early morning or late afternoon during winter, and traps smoke, dustand pollutants in the air.
The Environmental Health Management Department (Ministry ofHealth) has issued guidance to Provincial Departments of Health and CentralSubordinate Cities on health protection measures against the impact of airpollution. When the air quality index is very poor (201 - 300), ordinaryindividuals are advised to limit outdoor activities, exercise caution duringphysical activities, and favour indoor activities.
Avoiding high air pollution risk areas is recommended, and ifnecessary, using masks to prevent fine dust exposure. Public transportation isencouraged over motorcycles or bicycles, and opening windows and doors shouldbe limited during periods of heavy air pollution. Rinsing the nose, throat andeyes with saline can help ease irritation.
Sensitive individuals are recommended to completely avoid outdooractivities during heavy air pollution periods. If leaving the house isnecessary, minimise time spent outdoors and use masks that prevent fine dustexposure. If acute symptoms such as difficulty breathing, coughing, or feverarise, seeking immediate medical attention for examination, consultation andtreatment./.
VNA