To evaluate the environmental impact of E10 gasoline, the Ministry of Industry and Trade requested air quality monitoring data from environmental agencies under the Ministry of Agriculture and Environment.

During the initial phase, the ministry received monitoring data from Hanoi and Ho Chi Minh City.

Dao Duy Anh said measurements were collected from three monitoring stations in each city at two points in time - late May and late June 2026 - to compare air quality before and after the nationwide rollout of E10 gasoline, which began on June 1, 2026.

Preliminary results indicate that concentrations of several pollutants, including carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC), showed a downward trend.

However, the results differed between the two cities.

More evidence needed

Dao Duy Anh noted that air quality measurements at any given time are influenced by many factors, including traffic density, weather conditions, surrounding environmental conditions and wind speed.

As a result, although the initial findings suggest declining pollutant concentrations, they do not provide sufficient evidence to conclude that the improvement is directly attributable to the use of E10 gasoline.

He said longer-term monitoring with more frequent measurements is needed before scientists can make a comprehensive assessment of E10's impact on air quality.

The ministry has therefore instructed relevant agencies to strengthen environmental monitoring and continue tracking key air quality indicators, including PM2.5, PM10, CO, NO₂, NOx, SO₂ and O₃, in Hanoi, Ho Chi Minh City and other major urban areas.

Authorities also plan to expand the number of monitoring stations with complete datasets.

The ministry said future assessments will combine air quality data with information on E10 fuel consumption, traffic volumes, meteorological conditions and localized emission sources to provide a more objective and scientifically robust evaluation of the environmental effectiveness of Vietnam's biofuel policy.

Initial report showed mixed but positive signs

Earlier, a government task force responsible for implementing Circular No. 50 submitted a report to Deputy Minister of Industry and Trade Nguyen Sinh Nhat Tan on the progress of Vietnam's E10 gasoline rollout through July 1.

The report analyzed air quality data collected in Hanoi and Ho Chi Minh City at three different periods: early May, late May and late June 2026.

According to the task force, the data indicates an initial improvement in air quality, although the results were not consistent across locations or pollutant categories.

In Hanoi, compared with late May, concentrations of fine particulate matter had declined significantly by late June, with PM2.5 falling by 31% and PM10 by 29.6%.

In Ho Chi Minh City, improvements were broader and more pronounced. Compared with late May, monitoring data collected at the end of June showed PM2.5 declining by 15.7%, PM10 by 14.3%, CO by 65.2%, NO₂ by 68.6%, NOx by 57.6%, SO₂ by 38.5%, and O₃ by 14.4%.

The report concluded that both particulate matter and gaseous pollutants showed an overall downward trend following the introduction of E10 gasoline, although further observation will be needed to determine whether the fuel was the primary cause.

Tam An