Photochemical smog is caused by the interaction of solar ultraviolet radiation, engine exhaust emissions and industrial emissions.

It has become a frequent phenomenon in recent years, especially during the hot and dry summer months. Photochemical smog is widespread in large cities such as Hà Nội and HCM City, posing increasingly serious risks to public health.

The Centre for Environmental and Natural Resources Monitoring in HCM City has warned people, especially children, pregnant women and elderly, against going out. The department has recommended the use of masks and glasses to cover the face, especially eyes.

The phenomenon of photochemical smog is said to be cyclical, directly affecting health and quality of life. It is attributed to high urban density and traffic congestion. To make matter worse, HCM City residents have been inhaling polluted air from industrial parks located in the two neighbouring  provinces of Đồng Nai and Bình Dương.

Photochemical smog is a common phenomenon in traffic hot spots in HCM City where the level of air pollution exceeds the permissible limit.

According to a report of the centre, the concentration of air pollution has exceeded the permitted level in major traffic points in HCM City in recent days, such as Cát Lái Port, An Sương intersection, Gò Vấp area, Đinh Tiên Hoàng and Điện Biên Phủ streets.

The most polluted area is An Sương where dust concentration has exceeded 97 per cent and noise levels have exceeded 100 per cent against the permissible level. Smoke from cars and motorcycles caught in traffic is one of the major causes of air pollution.

Last year, HCM City had some 10 million kinds of transport vehicles, and approximately two million vehicles were used for commuting from provinces to cities. Non-maintenance of many old vehicles is also one of the causes of excessive air pollution.

Hồ Quốc Bằng, head of air pollution and climate change office at the Việt Nam National University-HCM City’s Institute for Environment and Natural Resources, said air pollution was a problem in the city all through the year.

The levels of air pollution exceeded regulations on synthetic dust by 1.5-2.2 times. This was affecting millions of people, but they were not aware.

The City People’s Committee has approved investment for expanding the network of air monitoring stations from 20 to 34 and for building more such automated stations.

A leader of the city Department of Natural Resources and Environment said to control air pollution in the city, the department was examining the sources of exhaust gases in industrial parks. They also proposed to the city authorities to invest in increasing the green cover of the city. — VNS