EA - Should UV stability of plastics be a concern for far-UVC adoption? by Sean Lawrence

Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Should UV stability of plastics be a concern for far-UVC adoption?, published by Sean Lawrence on September 1, 2023 on The Effective Altruism Forum.TL;DR: Some plastics degrade under exposure to UV light and I am concerned this could hamper widespread adoption of far-UVC. This post outlines the rationale for these concerns and seeks feedback from the far-UVC community on their importance.My simplified line of reasoning is:Epistemic status: this post is the culmination of spending ~5-10 hours thinking, researching, and writing up this post. I feel pretty certain that UV stability is worth at least thinking about with respect to far-UVC adoption but very uncertain about it being something that blocks far-UVC adoption. I have spent some time learning about far-UVC through discussions, reading, and preparing to interview someone in the space for a podcast but don't feel I have a very deep understanding of the space.SummaryUV light damages plastics that are not UV-stable. Many of us may have encountered this in cheap outdoor furniture whose plastic components change colour or become brittle and break easily after being left out in the sun too long. My concern is that if most of the plastic materials used in indoor materials are not UV-stable - meaning they undergo irreversible physical changes when exposed to UV light - then placing far-UVC lights indoors could cause unwanted damage to plastics and limit the demand for far-UVC.In this post, I focus on two ways by which this damage could hamper the uptake of far-UVC: consumer preferences on aesthetic effects and building regulations on physical degradation. These may not be the only ways and I'm uncertain about how concerned to be about each of them. However, I think they illustrate why the UV stability of plastics is concerning to me and why I'd like to see more research into it.Both of these concerns could result in damping the market for early adoption of far-UVC. My impression is that demand for far-UVC will be required to bring down the cost of the technology. If the price of the technology remains high, this could inhibit adoption and make far-UVC an intractable defence mechanism for pandemics and global catastrophic bio risks (GCBRs).My aim with this post is to present my rationale behind this concern and get feedback from the far-UVC community on the magnitude of this concern relative to other bottlenecks in the space.Effects of UV light on plasticsThe aesthetic and mechanical effects of UV light on plastics are two examples of why I think this could be worth spending more time thinking about the UV stability of plastics. Of the two, I'm more worried about the mechanical effects as if mechanical degradation results in blocking the installation of far-UVC then this could be a significant issue for adoption.Aesthetic effectsTL;DR: Aesthetic changes to plastics may result in consumers being unwilling to adopt far-UVC lighting.The aesthetic effects of UV radiation on non-UV-stable plastics appear to primarily be colour change - notably a yellowing of plastics. Other aesthetic effects that I'm less certain about and would ideally like to research more are cracking, stickiness, chalkiness that rubs off on contact, and texture change (eg. increased roughness). The aesthetic effects seem significant from a personal preference point of view - I wouldn't want all the plastic surfaces in my home or office to turn yellow over time.A recent study on the use of far-UVC on public transport buses simulated 6.2 years of exposure to far-UVC light and found "...that far-UVC radiation at 222 nm causes significant colour degradation in all the polymeric materials tested. The degree of color degradation varies depending on the type of polymeric material and the duration of exposure to far-UVC radiation. An obvious color di...