Hanoi: Polluted winter air is higher than summer

This statement of Professor Pham Duy Hien, former Director of Da Lat Nuclear Institute also affirmed: the highest level of air pollution is in December, January, the lowest is July and August.

According to the author, the reason for this situation, because the winter usually has a northeast monsoon coming in, the air pressure increases, the temperature drops, causing the air to be confined, pollutants are difficult to spread and fly away. This makes pollutants close to the ground for a long time.

Air pollution in Hanoi is even heavier in winter.(Photo: Pham Yen)

Mr. Hien warned, because of the radiation, so in the winter, there was a phenomenon of inversing heat to the ground at night. Therefore, the Center for Hydro-meteorological Forecasting should study and forecast air quality at the time of inversion. By rising 100 meters, the temperature dropped by 0.6 degrees.

But when the heat-up occurs, the temperature increases with altitude, causing pollutants to not spread high but accumulate within 150-200 meters close to the ground.

This causes a spike in suspended particles of less than 1% millimeter (PM10). This type of dust easily penetrates into the respiratory tract of people, affecting health, especially those with age.

According to the observation results of Lang meteorological station (Northern Hydrometeorological Center Center), currently, every cubic meter of air in Hanoi has 80 mg of gas dust of PM10, 45 mg SO ₂ , 30 mg NO ₂ , 30 mg CO ₂ , 30 mg 03 and 1000 mg CO.

When heat inversion occurs, most of these pollutants are elevated, in which gas dust increases the most.