according to the sources of NASA in their records that go from 1884 to 2018
the earth presents imbalance from 1920 (it can be presumed due to wars, migration and nuclear tests).after the second world war (1939-1945) from 1950 apparently the world calms down again.but as a consequence of the industrial revolution during the 20th century, it is when air pollution reaches its most critical points until today.