**1.1 Addressing the need for disinfectants**

A dichotomy of virology work is the need for both viral presence within the confines of research and the equally consistent need to establish pathogen-free research spaces. Throughout the world, contagious disease through viral contamination is an ever-present concern, and SARS-CoV-2 has brought the need to decontaminate to the forefront of virtually every industry. Scientific industries performing research, manufacturing pharmaceuticals, or providing healthcare services, all employ protocols for the disinfection of their environments in order for safe, successful, timely work to take place. These industries depend upon disinfection chemicals, and perhaps just as importantly the chemical delivery systems, that ensure the integrity of their work, personnel safety, and efficient transition from one research project or product type to the next.

### **1.2 Classification of antimicrobial effectiveness**

Today, a number of distinct categories are used to classify and understand disinfection methods. Disinfection chemicals are tested with established protocols and classified according to their relative success at eliminating specific pathogens. The *Biosafety in Microbiological and Biomedical Laboratorie*s (BMBL) 6th edition makes a distinction between the inactivation of pathogens (rendering them nonviable) and the destruction of pathogens and their infectious particles (decontamination) [1]. This distinction is highly relevant to industries where establishing a sterile surface can be a critical determinant of success or failure [2]. The United States Environmental Protection Agency (EPA) classifies disinfectants by their ability to inactivate certain challenging pathogens, such as *Clostridioides difficile* (*C. diff*) and *Bacillus anthracis* (Anthrax), which delineates if the disinfectant is classified a sterilant, decontaminant, or sporicide [3] (**Box 1**). This delineation is based on the Spaulding classification, the microbiological hierarchy model standard, which classifies pathogens based on their environmental hardiness and relative resistance to disinfection [8, 9]. In this hierarchy, small non-enveloped viruses are considered moderately resistant, whereas spores are most resistant to disinfection methods. Beginning in 2016, the EPA developed its Emerging Viral Pathogen category to fast-track products proven against bacterial spores for use against newly appearing viral threats [9–12]. Beyond this classification testing, commercially available spore-based biological indicators can be used with certain solutions as an ongoing measurement and verification of sterilization results [2].


#### **Box 1.**

*Definitions. Definitions relating to achieving and evaluating levels of antimicrobial effectiveness on environmental surfaces [1]. Definitions of substance phase or classification [4–7]. Depending on device design, the chemical being dispersed throughout the treatment space may be delivered in a variety of forms, phases, or states of matter. These definitions are provided for the sake of our understanding the differences in technologies and delivery methods described within this chapter.*
