Source: Department of Meteorology and Hydrology

MEASUREMENTS taken by the Department of Meteorology and Hydrology have revealed that rainwater in some areas of the country contains high levels of acid but still falls short of the amount required to be defined as acid rain.

Acidity and alkalinity levels in soil and water are measured on a pH scale ranging from 0 to 14, with a pH of 7.0 said to be neutral, pH below 7.0 acidic and pH above 7.0 alkaline.

Acid rain is defined as precipitation with a pH below 5.0.

“We have seen areas in Myanmar where the rain has a pH level as low as 5.2 and we are watching closely, but we still don’t have acid rain yet,” said U Htun Lwin, the director general of the department.

“The rain in eastern parts of Myanmar, especially in the Shan, Kayin, Kayah and Bago regions, has more acidity than the rest of the country,” he said.

According to data released by the department, the lowest pH levels (5.2) have been recorded in Myitkyina and Taunggyi, followed by Bago (5.3). Yangon’s rain has been measured at 5.9 and Mandalay’s at 6.8.

Acid rain is caused when oxides of carbon, nitrogen and sulphur – often released as pollutants from burning coal and other fuels, certain industrial processes and even volcanic eruptions – reach the atmosphere and react with hydrogen, transforming into acids.

These pollutants, when absorbed by water vapours, often fall back to the earth in the form of damaging acid precipitation.

“If the pH goes under 5.0, some aquatic animals cannot survive,” U Htun Lwin said. “Acid rain can also cause deforestation and damage to crops, and it can cause rapid weathering to statues and buildings.”

He said he sees the threat of acid rain as originating in areas outside of Myanmar because “we don’t have many factories that produce substantial amount of damaging gases and we don’t have volcanic eruptions”.

“For example, there is a volcano on Barren Island in Indian waters in the Andaman Sea that is throwing ash 10,000 feet into the air. Although it’s far from Myanmar we’re watching to see if the wind carries the ash into our country,” he said.

U Htun Lwin said the department is conducting quality tests on rain and river water in its labs.

“Since becoming a member of EANET (the Japan-based Acid Deposition Monitoring Network in East Asia) last year we have been able to be more active in conducting tests,” he said, adding that the department also plans to carry out air-quality tests in coming years.