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(ECNS)-- An international team recently claimed that they have busted the mystery behind a fatal fog that shrouded London for five days and killed some 12,000 people in the winter of 1952, and discovered the difference between it and smog in China. The 1952 London fog is widely known as a result of excessive coal burning, but why the combination of pollutants and humid weather was catastrophic was just fully revealed by a team of scientists from the U.S., China, Israel and UK. Through lab experiments and atmospheric measurement conducted in China, the team found that the 1952 London fog and smogs in China have similar chemical reaction processes, according to Beijing-based Science and Technology Daily. Scientists determined that sulfuric acid particles were the main culprit in 1952. But different from the London fog, smog in China involves much smaller nanometer-level particles, which are also neutralized by ammonia that comes mainly from car emissions and fertilizer use. The London fog was highly acidic, while smog in China is basically neutral, the scientists say. The study revealed how sulfur dioxide was turned into sulfur acid. The team said the process was facilitated by nitrogen dioxide, another co-product of coal burning, which also occurs in natural fog. The team added that natural fog contain larger particles of several tens of micrometers in size, and that the acid formed was sufficiently diluted. When the fog particles evaporated, the smaller acidic haze particles were left to blanket the city. The same chemistry also affects China's smoggy weather, said Zhang Renyi, a distinguished professor at Texas A&M University and member of the research team. As China is making attempts to combat air pollution, the study may provide some helpful insights, Zhang added. |
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