Another key aspect in the conversion of sulfur dioxide to sulfate is that it produces acidic particles, which subsequently inhibits this process. Our results showed that this process was facilitated by nitrogen dioxide, another co-product of coal burning, and occurred initially on natural fog. “But how sulfur dioxide was turned into sulfuric acid was unclear. “People have known that sulfate was a big contributor to the fog, and sulfuric acid particles were formed from sulfur dioxide released by coal burning for residential use and power plants, and other means,” Zhang says. Through laboratory experiments and atmospheric measurements in China, the team has come up with the answers. The 1952 killer fog led to the passage of the Clean Air Act in 1956 by the British Parliament and is still considered the worst air pollution event in the European history. It has long been known that many of those deaths were likely caused by emissions from coal burning, but the exact chemical processes that led to the deadly mix of fog and pollution have not been fully understood over the past 60 years. Recent British studies now say that the death count was likely far higher – more than 12,000 people of all ages died from the killer fog. Thousands of animals in the area were also killed. 9, at least 4,000 people had died and more than 150,000 had been hospitalized.

Visibility was reduced to only three feet in many parts of the city, all transportation was shut down and tens of thousands of people had trouble breathing. In December of 1952, the fog enveloped all of London and residents at first gave it little notice because it appeared to be no different from the familiar natural fogs that have swept over Great Britain for thousands of years.īut over the next few days, conditions deteriorated, and the sky literally became dark. Haynes Chair of Atmospheric Sciences and Professor of Chemistry, along with graduate students Yun Lin, Wilmarie Marrero-Ortiz, Jeremiah Secrest, Yixin Li, Jiaxi Hu and Bowen Pan and researchers from China, Florida, California Israel and the UK have had their work published in the current issue of Proceedings of the National Academy of Sciences (PNAS). Texas A&M researcher Renyi Zhang, University Distinguished Professor and the Harold J. The exact cause and nature of the fog has remained mostly unknown for decades, but an international team of scientists that includes several Texas A&M University-affiliated researchers believes that the mystery has been solved and that the same air chemistry also happens in China and other locales.

Few Americans may be aware of it, but in 1952 a killer fog that contained pollutants covered London for five days, causing breathing problems and killing thousands of residents.

London fog 1952