Reduced air circulation and cold winter temperatures have combined to create what is one of the most intense pollution events in history over China. Unhealthy polluted air blankets three fourths of a country the size of Europe. It’s as if the entire United States east of the Mississippi was choking under a cloud of pollution at a level considered "extremely hazardous" in Western countries. It is the worst pollution event ever recorded in China, and could be the worst pollution event ever caused strictly by manmade emissions.
Ironically, a decline in air circulation due to an evening out of temperatures between northern and mid latitudes is one of the most serious hazards predicted by global warming models. What has happened in China is that the jet stream has dropped far to the south, preventing air circulation over the entire country. Unlike the west, China has little effective pollution control. Additionally, the government is hesitant to release data that it considers embarrassing, so the true extent of the problem the country is experiencing may not be known.
On Saturday, January 12, the US Embassy in Beijing reported an air quality index of 755, based on measurements taken from its own instruments. This was the highest reading recorded since records began being kept at the embassy, and is far above what was considered the "maximum" limit of the scale, which was 500. Air pollution this extreme is hazardous to all human beings and animals, not just the very young, the very old and those with impaired lung function.
It is anticipated that pollution levels in China will slowly drop over the next few weeks. The cloud of pollutants will reach the American west coast by the end of January, and will cause pollution levels to rise from Los Angeles to Vancouver, but not to extreme levels.