First, they collected 850,000 tweets that used e-cigarette-related keywords from January 2012 through December 2014.
ຫນ້າທໍາອິດ, ພວກເຂົາໄດ້ລວບລວມ 850,000 tweets ທີ່ໃຊ້ຄໍາໂຄສະນາກ່ຽວກັບຢາສູບອີເລັກໂທຣນິກຈາກເດືອນມັງກອນ 2012 ເຖິງເດືອນທັນວາ 2014.