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Published December 13, 2019 4:37am

Photochemical smog: Dangerous pollution phenomenon

According to the Ministry of Environmental Resources, photochemical smog is a form of air pollution caused by the interaction between the sun's ultraviolet radiation and an atmosphere polluted by exhaust gases from motorbike engines. Industrial emissions.

In Viet Nam this phenomenon have begun to appear more frequently in recent years, especially during the hot, dry summer months. This phenomenon is especially evident in large cities such as Hanoi and Ho Chi Minh City due to the combination of many sources of air pollution.


The national environmental status report for the period 2011-2015 also shows that dust pollution tends to maintain high thresholds, especially in Hanoi and localities with strong industrial activities.

Specifically, PM10 dust concentration at Nguyen Van Cu station (Hanoi) in 5 years exceeded the standard by 1-1.2 times, in 2014 this index was 1.4 times higher.

The air quality index (AQI) has also increased, many large cities are at 201-300, and some days the quality declines to bad and dangerous levels. According to the human health impact assessment scale, if the AQI index is at 51-200, the group is sensitive to environmental pollution and should be limited outside; With an AQI above 300 people should stay home.

The NO2 index measured in urban areas is exceeding the limit. The annual average NO2 concentration in Hanoi increased 1-1.3 times. The monitoring station in Quach Thi Trang commercial area (Ho Chi Minh City) recorded it exceeding 2 times.

A representative of the General Department of Environment said that dust and emissions from urban traffic activities are still the main sources of pollution.

In addition, the report also assessed that part of the cause of photochemical smog pollution is due to cross-border pollution. Vietnam is an area affected by China's air pollution as well as forest fires in Indonesia.


Viet An Enviro is the unit with the number 1 market share in Vietnam in the field of consulting and manufacturing Continuous Automatic Environmental Monitoring Systems. With 08 general solutions: Waste water, River water, Ground water, Clean water, Sea water, Chimney emissions, Ambient air, Meteorology.

By Admin Viet An Group

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