How did the London tragedy happen?

1 London Haze Event 1952 12 In February, the traffic in London was almost paralyzed. On the fourth day of smog, a double-decker bus can only drive slowly in the city with fog lights. 1958+0952, the police in London used burning torches so that they could see others clearly in the smoke and be seen. It is called "Fog Capital" in the world. It is often shrouded in dense fog, like a mysterious veil. According to statistics, foggy days in London can be as high as seventy or eighty times a year, and there is a "foggy day" on average for five days. Whenever the fog comes, it not only affects traffic and causes accidents, but also directly harms people's health and even threatens people's lives. Compared with the situation of 1952, London today is a clean city. There are many factories not far from the city center. Most residents burn coal to keep warm. A steam locomotive powered by coal is pulling the train into the capital. There is little control over the exhaust gas produced by cars and trucks. On February 4th, 2005, at 65438 and 65438, the world's worst "smog" event occurred in London: the dense fog lasted for nearly a week, and a lot of smog and gas emitted by factories and residents were at low altitude. After the fog cleared, more than 8000 people died. This is the "fog disaster" that shocked the world. On the morning of February 3, the London Meteorological Observatory reported that there was a gas peak at night, and the temperature at noon could reach 5.6℃ and the relative humidity was about 70%. For the local people, this is a rare good day-a beautiful day. Clouds of dense fog from the chimneys of factories and urban families in central England were blown away from the clouds, so the air became very fresh and pleasant. However, no one would have thought that disaster was coming quietly. At night, London is on the southeast edge of a huge high-pressure cyclone, and the stronger north wind is blowing clockwise around the anticyclone. The next day, 65438+February 4, the cyclone center has reached hundreds of kilometers west of London. Move southeast along the usual path. The wind speed decreases in the morning, and clouds almost cover the whole sky. At noon, dark clouds covered all the sun, and the sky over London was overcast. The thermometer of the meteorological station read 3.3℃, and the relative humidity rose to 82%. 65438+February 5, an abnormal situation occurred. The anemometer at the London Meteorological Observatory detected a very strange measurement result-the wind speed reading was completely static. According to experts' estimation at that time, the wind speed did not exceed 3 kilometers per hour. London is in a dead wind, and a lot of smoke and dust have accumulated in the air for a long time. The wind is too weak to take away all kinds of harmful smoke and dust emitted by factories and families. As a result, a lot of soot fell from the air, and the beautiful Thames valley was blackened by smoke. Smoke enters Greenwich residents' homes through doors, which makes people miserable ... Fog clouds have been suspended over the city for five days and gradually become dirtier and more poisonous. The amount of smog in the air in central London has increased by nearly 65,438+00 times. Smoke makes thousands of victims suffer from bronchitis, asthma and other diseases that affect the lungs. Finally, it is the smog of 65438+February 10. It is estimated that 4000 people have died, most of them are elderly people. Today, the main cause of smog is the exhaust pollution from motor vehicles. In big cities such as Los Angeles and Mexico City, smog has been suspended in the air. Using unleaded gasoline and installing catalytic converter for locomotive exhaust gas will help reduce the health damage caused by this pollution. However, this is still an urgent problem.