In March, although the PM 2.5 dust concentration continued to go up in Hanoi it decreased more than in January and February. In other cities, the air quality in March maintained quite well.
The General Department of Environment (Ministry of Resources and Environment) identified seasonal fluctuations in the weather along with a reduction in the amount of transportation, several production and services activities due to the impact of the COVID – 19 pandemic that has significantly improved air quality.
Air quality has improved since March 2020
The level of pollution has decreased
Last March due to the stage of the changing season, the average day temperature rises higher than the previous months, but there is still cold air in the North. However, this is accompanied by moist rainy days changing from the previous dry weather.
“There are weather elements combined with the minimizing of production activities, and transportation… due to the influence of COVID – 19 pandemic that has made the air quality in Hanoi and other cities of VietNam fluctuate,” the general Department of Environment said.
Although the concentration of PM 2.5 dust continues getting higher in Hanoi, the level of pollution has decreased more than in January and February. For other cities, the air quality in March is maintained quite well with all parameters characteristic for the ambient air that is under the government’s standard.
Air observation results for March 2020 show that most cities across the country had an average 24 hours concentration of PM 2.5 dust under the standard of VietNam’s ambient air quality (05:2013/BTNMT)
Average 24-hour performance of PM 2.5 in some cities of Vietnam in March, 2020
Hanoi still has bad air quality days
In Hanoi, according to the General Department of Environment, there are still days when the 24 hours value of the PM 2.5 parameter exceeded the limit, concentrated mainly in the 2nd week of March. This is also the period showing the most fluctuation. March 07 – 09,from the early morning to the afternoon, the temperature rose quite high. On March, 09, temperatures were up to 32 Celsius degrees. On March 16 due to the influence of cold air and cloudy weather there was also a day of a 24h average of the highest PM 2.5 in 3 months, which exceeded 2 times over the allowable limit of QCVN.
Evaluation of air quality according to the AQI index showed that in Hanoi, 13/31 days the air quality was poor (AQI from 101-150), especially between March 6 and March 17.
Monitoring the air quality variation in the inner city areas of Hanoi, the results of the monitoring show that there areas with an average of 24h value of PM 2.5 exceeding the limits of the standard, focusing mainly in period from March 06 – March 17. However, pollution levels are less than January and February
From the Lunar New Year to now, due to the COVID – 19 pandemic there were complex variables including the fact that all universities and, secondary schools were closed. The amount of vehicles in the city was reduced so pollution due to traffic activity also decreased. From March 20 to the end of March, the 24 hours value of PM 2.5 continued to decrease.
Air quality is mainly as per the average but continues to improve
The current AQI index shows results in Hanoi’s stations in the past 3 months, there are still 02/31 days (March 09 and March 16) with poor air quality (AQI from 151 – 200), 09/31 days on poor air quality (AQI from 100 – 150). At the end of 3 months (from 24 – 31/3), air quality is mainly as per the average but continues to improve.
Monitoring the day’s performance for the high-level air pollution (March 15 and 16), the results of the monitoring show that its peak of the PM 2.5focused on night and early morning time, this is also the moment of the heaviest fog of the day. During this time dust particles can not be diffused into the air.
The General Environmental Department noted they should continue to monitor the air quality movement, especially the period beginning on March 28 (after the Prime Minister issued Directive No.15, which requires the suspension of the operation of the service business establishments, limiting the transport between Hanoi, Ho Chi Minh City, thereby reducing the public transport activities…) and from April (after the prime Minister continues to release Directive No. 16 on social isolation; minimize the production activities, service, suspension of public transport activities, such as buses, taxis, passenger car services…). Thereafter there may be more specific reviews of the impact of production activities, transportation to the air quality of urban areas
Source: Báo Tài nguyên và Môi trường