Londoners are accustomed to fog, but not like the one that rolled in — and stayed — during the winter of 1952.

The impenetrable fog, seeded with soot and noxious smoke from perhaps a million coal heating fires, suffocated the city for five days. The death toll was astounding — an estimated 12,000 people.

Kate Winkler Dawson examines this environmental disaster in “Death in the Air: The True Story of a Serial Killer, the Great London Smog, and the Strangling of a City.” As the title emphasizes, she stirs another mass killer into the mix — John Reginald Christie, who went to the gallows after a killing spree that involved eight victims.

Don’t be fooled, though, into thinking that Christie used the cloak of the fog to commit his deeds. The link between the killer fog and the serial killer exists only in the author’s construct. Christie’s killing spree began nine years before the 1952 fog, and none of his victims was killed while the fog held its grip on London; his killing spree ended three months after the fog lifted.

Although the fog and the Christie killings remain two distinct, alternating strands, each story is compelling.

The fog resulted from a weather system that trapped a mass of air over the greater London area and its 8 million inhabitants. This peasouper was so thick, with visibility reduced to several feet, that it essentially halted normal life in the city.

Bus service and car traffic came to a halt. Sporting events were canceled. The haze seeped indoors, too, forcing cinemas to close because moviegoers couldn’t see the screens. Ambulances took hours to answer calls, because it was unsafe to drive any faster than a walking pace.

Quickly, the fog morphed from simply annoying to toxic. Only seven years removed from World War II, high-quality coal was still rationed, and the government encouraged people to burn “nutty slack,” a cheap, low-grade coal that spewed soot and pollutants. As tons of sulfur dioxide and carbon dioxide accumulated in the stagnant air, Londoners choked, hospitals ran out of beds, and funeral homes soon ran short of wreaths.

Dawson recounts the facts of the disaster clearly, but she falls short in capturing the human toll. She focuses mostly on one family in which the father died, describing their ordeal in great detail. This singular approach fails to convey the scope of the suffering and heartache as thousands succumbed.

Now, back to the other killer.

Christie, an undistinguished clerk, lived in an apartment in the low-rent part of London, the now-fashionable Notting Hill. He murdered what is believed to be seven women, including his wife, and the year-old daughter of one of his victims.

Adding to the tragedy is that the baby’s father was hanged for her death, although he was most likely innocent and was pardoned posthumously. Dawson is at her strongest here, as she details how Christie’s lies helped convict the innocent man.

Though written in a sometimes lurid style, as if the author had read too many penny dreadfuls, “Death in the Air” is an enlightening look at two lesser known but important events in British history, for both had far-reaching consequences.

Four years after the fog, the U.K. enacted the world’s first comprehensive air pollution law. And in 1965, with the innocent man’s execution as a key factor, Great Britain ended capital punishment.

Dennis J. McGrath is an editor at the Star Tribune.

Death in the Air
By: Kate Winkler Dawson.
Publisher: Hachette, 341 pages, $27.