1Materials and methods 1.1 Ultraviolet ray sterilizer (Shanghai Yuejin Medical Optical Instrument Factory) with a radiation intensity of 90μW/cm2; KTG2120 Dynamic Air Sterilizer (Jiangsu Juguang Optoelectronics Technology Co., Ltd.); Air Microbial Sampler (BioMérieux) Ordinary agar culture dish (diameter 9cm).

1.2 Methods Sterilize the blood donation room and the blood collection room using a dynamic air sterilizer (hereinafter referred to as the sterilizer method) and a UV lamp sterilizer (hereinafter referred to as the ultraviolet method). Air sterilizer turned off after 1h. Sampling before uncollected blood (hereinafter referred to as static environment). Under the working conditions of the blood donation room and the blood collection room (hereinafter referred to as the dynamic environment), the work is sampled after 1-3 hours of operation (the dynamic air sterilizer is continuously turned on while working).

1.3 Sampling The airborne microbial sampler is used to detect the total number of bacteria in the air. The principle is to collect bacteria in the air by inhaling a certain amount of air, separating the substances from the air stream and hitting the agar surface. Five points in the east, south, west, north, and middle of the blood collection room and general laboratory were set up. The east, south, west, and north points were all 1 m from the wall, and the sampling height was 120 cm. At each sampling point, the amount of air collected by the airborne microbiological sampler was 50L (0.05m3). The sample was collected on agar plates and incubated at 37°C for 48 hours. The number of colonies was counted and calculated by the following formula: Number of air colonies (cfu/ M3) = number of plateau colonies (m3)

1.4 The number of qualified air colonies is ≤500 cfu/m3.

1.5 Statistical analysis The data obtained were expressed as the mean ± standard deviation (x ± s), and the difference between the two methods was compared using the t-test.

2 results (1-3)

Comparison of the effects of two different disinfection methods on air disinfection of blood donation houses (x±s)n Number of bacterial colonies (cfu/m3) Bacterial killing rate after disinfection () Number of mold colonies (cfu/m3) Mould kill after disinfection Kill rate () Sterilizer method 20485 ± 9140 ± 3010.140 ± 225 ± 287.5 UV method 20501 ± 144197 ± 14457.940 ± 2025 ± 1037.5 Note: Bacteria (mold) kill rate = [(pre-sterilization number of colonies - number of colonies after disinfection) / Colonies before disinfection] × 100

2 Total number of air colonies and mold counts (x±s) n sampled after working for 1-3 h. Work 1 h (cfu/m 3) Number of colonies Fungal number Work 2 h (cfu/m 3) Number of colonies Fungal number Work 3 h (cfu/m 3) The number of colonies and mold dynamic air sterilization method 2050 ± 225 ± 375 ± 504 ± 2102 ± 8011 ± 2 ultraviolet disinfection 20131 ± 3020 ± 3272 ± 5040 ± 3512 ± 8059 ± 3 Note: 1 and 2h sterilizer method compared the number of colonies, t=1.

852, P>0.05; 2,3 h colony count comparison t=1.973, P>0.05; ultraviolet assay 1, 2 h colony count comparison, t=3.012, P<0.01; 2,3 h colony count comparison t=3.249, P<0.01.

3 Comparison of disinfection effects of sterilizer method on two different blood collection sites (x±s)n Work 1h (cfu/m3) Number of colonies Fungal number Work 2h (cfu/m3) Number of colonies Fungal number Work 3h (cfu/m3) Colonies The number of blood mold chambers 2040±205±242±22036±200 blood donation house 2050±225±365±254±270±305±2

3 Discussion UV disinfection and ozone disinfection is currently the most economical and practical method of air disinfection, but UV is susceptible to dust, objects blocking, and affect the disinfection effect, and the human body for a long time under ultraviolet irradiation, can easily cause skin erythema, conjunctival irritation Even adverse reactions such as skin cancer have occurred. The ozone disinfection method can cause human neurotoxicity, dizziness, headache, memory loss and so on. Therefore, UV and ozone methods are only suitable for static disinfection. The method of disinfecting the dynamic air sterilizer is through the combined action of low-ozone, high-intensity ultraviolet light, electrostatic adsorption, and air filtration system to kill bacteria in the air. No ultraviolet rays and ozone leak during disinfection, and no harm to the human body. Therefore, the instrument can truly coexist with humans, perform dynamic disinfection, and continuously ensure a good blood collection environment.

From our experimental results, it can be found that with the extension of working hours, the total number of bacteria in the air is increasing because the ultraviolet rays cannot be turned on at work; and using a dynamic air sterilizer, the air quality of the blood collection room can reach the national standard of 100. It is obviously higher than the reports of some domestic medical institutions. At the same time, the dynamic air sterilizer can preset the start-up time, complete the air disinfection before work, and save the donors waiting time. From the results, it can also be found that in the blood collection room in the blood station, the killing rate of mold by the dynamic air sterilizer after 2 hours is 100.

In blood donation houses with high traffic flow, molds are still present in the air after long-term disinfection. Attention should be paid to this, and the number of airborne bacteria (including mold) can be reduced by controlling the number of individuals entering the blood collection room and guiding blood donors to move in a reasonable direction.