What was the primary cause of the london fog of 1952? a. global warming trapped hot air from blast furnaces in the lower regions of the atmosphere. b. cold air led to heavy use of coal, and the smoke from the coal fires was trapped close to the ground by a temperature inversion. c. effluents from steel factories raised the temperature of the thames river, producing increased water vapor that condensed as soon as it contacted the air. d. unusually strong winds pushed air up the slopes of nearby mountains, where it condensed into fog and was pushed back to the ground by a temperature inversion.