Participant's baby was born prematurely and had underdeveloped lungs at birth. Most premature infants require mechanical ventilation after birth, which increases the risk of lung injury and may lead to varying degrees of bronchopulmonary dysplasia (BPD). Investigators believe that introducing an air purifier into your home environment after Participant's baby is discharged could help improve their lung development. This study aims to non-invasively measure baby's transcutaneous carbon dioxide (PtcCO₂) levels and blood oxygen saturation (SpO₂) at home, both with and without the use of an air purifier. In addition, investigators will collect data from Kaohsiung Medical University Hospital medical records regarding the number of visits, respiratory status, height, weight, head circumference, and developmental progress. Health questionnaires will also be administered to assess changes in health outcomes and provide recommendations on improving indoor air quality in Participant's home.