哪个UVC源是最好的？222 nm vs. 265 nm for Disinfection of Air, Surface, and Water

Traditionally, efforts around disinfection methods were motivated by reducing infections resulting from pathogenic organisms. With the COVID-19 pandemic, there has been higher demand for documented and controlled disinfection methods to treat air and surfaces responsible for virus transmission. UVC light is proven to effectively inactivate most pathogens including drug-resistant bacteria and most strains of viruses. Conventional UV disinfection based on mercury (Hg) lamps have been used for such applications but safety concerns and regulations around banning the use of mercury have driven the development of alternative UV sources for disinfection.

新万博客户端are seen as the natural replacement for mercury lamps for several reasons: they are mercury-free, offer advantageous operating features (e.g. instantaneous on/off, ability to cycle without impacting lifetime, extraction of heat in the opposite direction of UVC light, high performance reliability control), and low costs of maintenance. These benefits have enabled the integration of UVC LEDs into a variety of disinfection applications in water and high-touch surfaces, increasing the quality of products and features to the end-users and reducing costs to OEMs.

However, recent studies have investigated the use of krypton-chlorine (Kr-Cl) excimer lamps as an alternative method to disinfect. The shorter wavelengths of these lamps are thought to limit human health hazard due to the strong absorbance in biological material, meaning the light does not penetrate far enough into multi-cell organisms (such as humans) to create long-term damage. However, the shorter wavelengths also lead to a different disinfection process. Here we review both technologies and their usefulness in a variety of applications.

紫外波长和消毒光谱敏感性

UV光谱区域范围为100nm至400nm，通常基于大气中的吸收和辐射的生物作用分为三个子区域：

• 乌瓦: 315 nm to 400 nm
• uvb.: 280 nm to 315 nm
• UVC: 200 nm to 280 nm

UVA和UVB通过地球的大气传播并具有有限的杀菌作用。On the other hand, UVC is completely absorbed by the earth’s atmosphere and is highly disruptive for live organisms because it is strongly absorbed by proteins (principally 210 nm to 230 nm) and the nucleic acids of DNA and RNA (principally 250 nm to 280 nm). The latter wavelength range is commonly referred to as the “germicidal UVC range。“

Thespectral sensitivityof a microbe is the relative ability of the microbe to absorb a photon as a function of wavelength over a range of wavelengths. Pathogens have a unique radiation absorption “fingerprint,” which means that they absorb photons differently at varying wavelengths. While different, each pathogen shows a peak absorption near 265 nm and diminishes rapidly above 280 nm in the UVB range. For the most pathogens, there is a steep drop in sensitivity below 250 nm.

Comparing the Impact of Far UVC and Germicidal UVC on Disinfection

Within the germicidal UVC range, 260 nm to 270 nm is seen as an ideal wavelength, with only a small drop in efficacy in damage to the nucleic acid across that wavelength range (peak DNA/RNA absorption is observed between 263 nm to 265 nm) while, outside that range, the efficacy of longer or shorter wavelengths starts to fall drastically.

The primary process of disinfection in the germicidal range is by the generation of cyclobutane pyrimidine dimers (CPD), the dominant form of UV-induced genomic damage. These dimers interrupt the replication of DNA/RNA and lead to bacterial cell death and viral inactivation.

最近，科学家研究了Krypton-溴和Krypton-氯准分子灯的应用，分别在207nm和222nm处产生初级光子发射峰。UVC在207nm至222nm范围内通常被称为远UVC。虽然在该范围内发射的光子被DNA / RNA的核酸吸收到一定程度上，但是据认为，减少感染性的主要因素导致蛋白质的吸收和所得到的损伤。这显着上表现出腺病毒，耐甲氧西林耐金黄色葡萄球菌（MRSA）和H1N1型流感病毒。

在水应用中，由于水新万博投注中的紫外透射率（UVT）变得不可接受地，因此使用222nm的使用似乎并不似乎。对于过滤水的UVT大致恒定至260nm，并且由于常见的化学污染物如硝酸盐，开始以较短的波长急剧下降。此外，感兴趣的病原体是生物膜形成细菌，例如具有260nm至265nm之间的峰值吸收的假单胞菌，其在更短的波长下表现出较低的光子吸收。

Employing a 205 nm to 230 nm photon source to treat pathogens is far more likely to depend on the protein aspect of a pathogen, which can have substantially different absorption coefficients, rather than the proven nucleic acid DNA/RNA approach utilizing the absorption peak in the 260 nm to 270 nm wavelength range which has been shown to consistently and predictably inactivate pathogens.

Commercial Readiness of Devices

UVCLEDs can be seen as attractive for a wide range of applications due to their low cost of ownership/maintenance and commercially viable price. For example, today, Crystal IS offers UVC LEDs at negotiated volumes in the price range of 10 to 15 cents per mW.

市售的UVC LED基于来自Al1-Xgaxn万博捕鱼手机游戏新万博客户端合金制造的半导体，并且它们的发光波长由其合金含量控制，这意味着也可以使UVC LED在222nm以下的波长下发射。因此，波长的问题不仅仅是准分子灯与UVC LED的问题。新万博客户端万博捕鱼手机游戏UVC LED在这些较短的波长下发射较高的Al摩尔分数，这导致较低的效率。新万博客户端万博捕鱼手机游戏例如，今天，晶体是商业UVC LED的大约一个数量级（倍数10）比230nm更高，比万博捕鱼手机游戏新万博客户端在230nm处更高，两个数量级强大;预计波长低于225nm的波长将在效率和力量中进一步降低。

因此，对于绝大多数病原体，在使用当今UVC LED技术时，杀菌范围的消毒水平将会高得多。万博捕鱼手机游戏与杀菌范围相比，腺病毒是222nm辐射的功效高达10（数量级）的效果，但甚至在此，低于230 nm以下的电流LED的较低功率和较短的寿命与杀菌范围相比，基本上提高了该波长范围内LED溶液的成本。

将准分子灯与UVC LED进行比较时，还有其他因素考虑仔细考虑。万博捕鱼手机游戏新万博客户端与UVC LED（通常为0.3cm的方形底座的长方体）相比，准分子灯（通常长于10cm的管）的占地面积意味着安装的灵活性是完全不同的。新万博客户端万博捕鱼手机游戏对于早期应用随着皮肤新万博投注直接暴露的准分子灯（到目前为止只携带有限的研究，但结果似乎表明没有看到永久性损害）。准分子灯需要昂贵的带通滤波器以去除较长的波长（例如，Krcl灯为222nm发射的XRCL灯在UVC中具有大约258nm和UVB的二级发射峰）。这将增加已有成千上万美元的产品的成本。

结论

The question on preferences for a specific UVC wavelength (e.g. 222 nm vs. 265 nm) depends on the application. Excimer lamps seem to find relevance for treatment of large areas with continued human passage, however limited studies have been investigating the effects of prolonged exposure on humans.

何塞莫迪，M.D.IND.S自由生物安全和麻省理工学院解决顾问和NASA Itech的顾问首席医学创新官，而虽然远UVC技术表现出很多承诺，但它还没有准备好黄金时段。“曝光的角度和持续时间仍未确定，”他说。“已经控制了迄今为止的曝光，并根据表面，织物和曲率的类型，[已经存在]混合结果。”

与汞灯相比，使用UVC LED不仅更为绿色，它在几种应用中具有商业上更具吸引万博捕鱼手机游戏新万博客户端力。新万博投注虽然人类不应直接暴露于UVC灯，但UVC LED的小足迹以及近点的光的光允许设计UVC辐射良好控制和不需要的暴露以防止健康危害的目标消毒应用。新万博投注新万博客户端万博捕鱼手机游戏此外，在连续运行时，虽然UVC LED的壁插效率（WPE）低于汞灯时，但在没有热预热时间的情况下，在没有预热万博捕鱼手机游戏新万博客户端时间的情况下将LED打开/关闭的能力转化为在寿命上的更​​高电气效率应用程序并允许记录，可预测和可靠的消毒。

如果您想了解有关此主题的更多信息，或者对Crystal制造的Klaran UVC LED感兴趣，请新万博客户端万博捕鱼手机游戏联系我们today.

参考文献（222 nm）

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