Lapse rateIt is defined as the rate at which atmospheric temperature decreases with increase in altitude.
Lifetime (in the atmosphere)The approximate amount of time it would take for the anthropogenic increment to an atmospheric pollutant concentration to return to its natural level (assuming emissions cease) as a result of either being converted to another chemical compound or being taken out of the atmosphere via a sink.
London SmogA contraction of fog and smoke that characterized air pollution episodes in London. Fog, with chemical and physical pollutants, remained there for four days in 1952 and 5 days in 1962. In 1952, 4000 people died while in 1962 about 700 died.