VietNamNet Bridge - Acid deposition and photochemical smog have appeared in recent years, mostly in summer months when the weather is dry and hot, especially in large urban areas such as Hanoi and HCMC.

According to Nguyen Van Thuy, director of the Environment Monitoring Center, besides domestic polluting sources, Vietnam is facing cross-border pollution as it is located next to countries with strong production such as China.

Thuy said Vietnam also bears influences from territories relatively far away from Vietnam. In winter, when the northeast monsoon comes down to the north, the pollutants from China are brought to Vietnam.

Though scientists still have not found clear signs of acid deposition, photochemical smog and cross-border pollution, there have been some certain signs. 

The acid deposition monitoring has detected contaminants from other countries. 

Mercury pollution is one of the most serious problems, according to Thuy, which is now a big concern for many countries.

On the map of mercury emissions in the world's atmosphere, scientists mark the entire east coast of China as dense with mercury emissions. Mercury from China spreads to neighboring countries such as Japan and Korea.

On the map of mercury emissions in the world's atmosphere, scientists mark the entire east coast of China as dense with mercury emissions. Mercury from China spreads to neighboring countries such as Japan and Korea.

There has been no official figure about the influences to Vietnam, but the influences are inevitable, because of the geographical position and favorable conditions for the spread (the northeast monsoon).

The Minamata Convention on Mercury, the global treaty to protect human health and environment from the adverse effects of mercury, created after an accident where thousands of people died of mercury infection on Miamanta Bay, has been ratified by 38 countries. 

The treaty will take effects when the number of ratified countries reaches 50. If so, a global monitoring network will be built to keep watch over the spread of mercury in the atmosphere.

Also according to Thuy, Vietnam has begun joining acid deposition, mercury spreading and cross-border pollutant monitoring network, and therefore, figures will be available soon.

Truong Manh Tien, chair of the Environmental Economics Association, also said that once mercury pollution from China spreads to Japan, South Korea and the US, Vietnam also suffers.

He said Vietnam needs to sign  international treaties to build up commitments between the two countries on cross-border pollution problems.

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