Assessment of occupational aerosol exposure for laboratory technicians: A quantitative study using ΦX174 phage as a substitute virus

This study aimed to clarify aerosol exposure risks throughout the workflow of a Biosafety Level 2 (BSL-2) polymerase chain reaction (PCR) laboratory, validate the suitability of the ΦX174 bacteriophage as an indicator virus, and provide evidence for biosafety control measures. The ΦX174 bacteriophage was used to simulate viral samples, and a concentration–bacteriophage plaque standard curve was constructed ( R ²=0.998). Five operational steps in a simulated PCR laboratory were quantitatively monitored for aerosol concentration using double-layer agar plates, with blank controls used to eliminate interference. Statistical analysis was employed to identify risk differences. Sample homogenization ((5.67 ± 1.23) × 10⁴ plaque-forming units (PFU)/m³) and nucleic acid extraction ((3.45 ± 0.89) × 10⁴ PFU/m³) were identified as high-/very high-risk steps. The viral load in the samples was strongly positively correlated with the aerosol concentration (r = 0.926, P <0.001), with aerosol levels linearly decreasing with increasing distance in high-risk steps. The ΦX174 bacteriophage demonstrated high detection sensitivity (10¹ PFU/ml) and demonstrated safety compatibility with BSL-2 laboratories. Aerosol risks in PCR laboratories exhibit step-specific differentiation, and ΦX174 serves as an ideal indicator virus. Proposed strategies such as equipment upgrades and personal protective equipment (PPE) grading can reduce exposure risks.