Editing James Lovelock (section)

=== CFCs ===
{{Main|Free-radical halogenation}}
[[File:AYool CFC-11 history.png|thumb|upright=1.2|Reconstructed time-series of atmospheric concentrations of CFC-11<ref>{{Cite journal |last=Walker |first=S. J. |last2=Weiss |first2=R. F. |last3=Salameh |first3=P. K. |name-list-style=vanc |year=2000 |title=Reconstructed histories of the annual mean atmospheric mole fractions for the halocarbons CFC-11 CFC-12, CFC-113, and carbon tetrachloride |journal=[[Journal of Geophysical Research]] |volume=105 |issue=C6 |pages=14285–14296 |bibcode=2000JGR...10514285W |doi=10.1029/1999JC900273 |doi-access=free}}</ref>]]
After developing his electron capture detector, in the late 1960s, Lovelock was the first to detect the widespread presence of [[CFCs]] in the atmosphere.<ref name="Lovelock-1971" /> He found a concentration of 60 [[parts per trillion]] of [[CFC-11]] over Ireland and, in a partially self-funded research expedition in 1972, went on to measure the concentration of CFC-11 from the northern hemisphere to the Antarctic aboard the [[research vessel]] {{RRS|Shackleton}}.<ref name="Lovelock-1973" />{{sfn|Lovelock|1988|p=164}} He found the gas in each of the 50 air samples that he collected but, not realising that the breakdown of CFCs in the stratosphere would release [[chlorine]] that posed a threat to the [[ozone layer]], concluded that the level of CFCs constituted "no conceivable hazard".{{sfn|Lovelock|1988|p=164}} He later stated that he meant "no conceivable toxic hazard".{{sfn|Lovelock|2000|p=216}}

However, the experiment did provide the first useful data on the ubiquitous presence of CFCs in the atmosphere. The damage caused to the ozone layer by the [[photolysis]] of CFCs was later discovered by [[Sherwood Rowland]] and [[Mario Molina]]. After hearing a lecture on the subject of Lovelock's results,<ref>{{Cite web |last=Rowland |first=F. Sherwood |last2=Molina |first2=Mario J. |name-list-style=vanc |date=7 December 2000 |title=CFC-Ozone Puzzle: Lecture |url=http://www.eoearth.org/article/CFC-Ozone_Puzzle:_Lecture |url-status=dead |archive-url=https://web.archive.org/web/20090216160905/http://www.eoearth.org/article/CFC-Ozone_Puzzle%3A_Lecture |archive-date=16 February 2009 |access-date=10 December 2007 |website=[[Encyclopedia of Earth]]}}</ref> they embarked on research that resulted in the first published paper that suggested a link between stratospheric CFCs and ozone depletion in 1974 (for which Sherwood and Molina later shared the 1995 [[Nobel Prize in Chemistry]] with [[Paul Crutzen]]).<ref>{{Cite web |title=The Nobel Prize in Chemistry 1995 |url=https://www.nobelprize.org/prizes/chemistry/1995/summary/ |url-status=live |archive-url=https://web.archive.org/web/20200522181342/https://www.nobelprize.org/prizes/chemistry/1995/summary/ |archive-date=22 May 2020 |access-date=30 July 2022 |publisher=[[Nobel Foundation]] |quote=...{{nbsp}}for{{nbsp}}... work in atmospheric chemistry, particularly concerning the formation and decomposition of ozone.}}</ref> Lovelock was sceptical of the CFC–ozone depletion hypothesis for several years, calling the US ban of CFCs as [[aerosol propellant]]s in the late 1970s arbitrary overkill.<ref>{{Cite book |last=Lovelock |first=James E. |title=Stratospheric Ozone and Man |publisher=CRC Press |year=1982 |isbn=978-1-351-07693-7 |editor-last=Bower |editor-first=Frank A. |volume=1 |location=Boca Raton, Florida |pages=195–201 |chapter=Epilogue |editor-last2=Ward |editor-first2=Richard B. |name-list-style=vanc}}</ref>