The global temperature records show the fluctuation of temperature from ocean to landraces and varying extremes. These have existed since the 1850 period when measured from the Pleistocene ice age by the use of various tools and techniques like the weather balloon radioscopy.
Tree ring and ice core data have shown a measuring record from 1000 to 2000 years of data, based on lake sediments, cave deposits and fossils records. The global mean surface temperatures have ranged for over 25 years of span with periods of little ice age and medieval warm periods.
I would say it would be true because even though you are visiting for 3 months you will still be breathing the polluted air for the 3 months thus it would affect a person in a negative way and it is true.
