Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Unhealthy Levels of Smog Choke Thai Capital for Over Week Associated Press BANGKOK - Unhealthy levels of smog have choked Bangkok for more than a week, as the Thai capital's residents fume over the ineffectiveness of government measures to combat the problem. As thick haze blanketed the city Monday, pollution levels soared to 95 micrograms per cubic meter of PM 2.5 particle at noon in some areas, according to the government's Pollution Control Department, which described that level as very unhealthy. The maximum level considered safe by the government is 50. PM 2.5 particles are small enough to penetrate deeply into the lungs, which can cause both short-term bronchial problems as well as serious long-term health issues. Bangkok's smog crisis results from still air and an excessive amount of ultrafine dust from vehicle emissions and other activities, Pollution Control Department Director-General Pralong Damrongthai explained in a Monday press release. He said smog is being trapped close to the ground by a blanket of warm air in what meteorologists call an inversion. .