IMPORTANCE: Controversy remains regarding the transmission routes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).OBJECTIVE: To review current evidence on air contamination with SARS-CoV-2 in hospital settings and the factors associated with contamination, including viral load and particle size. EVIDENCE REVIEW: The MEDLINE, Embase, and Web of Science databases were systematically queried for original English-language articles detailing SARS-CoV-2 air contamination in hospital settings between December 1, 2019, and October 27, 2020. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for ScopingReviews (PRISMA-ScR) guidelines. The positivity rate of SARS-CoV-2 viral RNA and culture were described and compared according to the setting, clinical context, air ventilation system, and distance from patient. The SARS-CoV-2 RNA concentrations in copies per meter cubed of air were pooled, and their distribution was described by hospital areas. Particle sizes and SARS-CoV-2 RNA concentrations in copies or median tissue culture infectious dose per meter cubed were analyzed after categorization as less than 1 μm, from 1 to 4 μm, and greater than 4 μm. FINDINGS: Among 2284 records identified, 24 cross-sectional observational studies were included in the review. Overall, 82 of 471 air samples from close patients’ environment (17.4%) were positive for SARS-CoV-2 RNA, without difference according to the setting (intensive care unit, 27 of 107[25.2%]; non–intensive care unit, 39 of 364 [10.7%];P< .01), the distance from patients (<1 m, 3 of118 [2.5%]; 1-5 m, 13 of 236 [5.5%];P= .20). The positivity rate was 5 of 21 air samples (23.8%) in toilets, 20 of 242 (8.3%) in clinical areas, 15 of 122 (12.3%) in staff areas, and 14 of 42 (33.3%) in public areas. A total of 81 viral cultures were performed across 5 studies, and 7 (8.6%) were positive, all from close patient environments. The median (interquartile range) SARS-CoV-2 RNA concentrations varied from 1 × 103copies/m3(0.4×103-3.1×103) in clinical areas to 9.7 × 103(5.1×103-14.3×103)in the air of toilets or bathrooms. Protective equipment removal and patient rooms had high concentrations per titer of SARS-CoV-2, with aerosol size distributions that showed peaks in the lessthan1 μm particle size region and staff offices in the greater than 4 μm particle size region. CONCLUSIONS AND RELEVANCE: In this systematic review, the air close to and distant from patients with coronavirus disease 2019 was frequently contaminated with SARS-CoV-2 RNA; however, few of these samples contained viable viruses. High viral loads found in toilets and bathrooms, staff areas, and public hallways suggest that these areas should be carefully considered.