###### Abstract
Another study from 2020 successfully developed a colorimetric paper-based sol-gel sensor to monitor freshness of fish via detection of the total volatile basic nitrogen levels through plastic film by incorporating bromocresol green into their synthesized material [20]. While there are often difficulties with many sensing materials in detecting chemical agents in the vapor phase, sol-gel synthesis has proven to be an effective adsorbent material for vaporous analytes [21, 22]. In general, sol-gel synthesis involves simple, low-cost procedures that allow for the design of an inexpensive product that can be easily distributed for widespread use. In theory, use of the sol-gel increases sensitivity as the vapor in the enclosed container will be absorbed into the three-dimensional sponge-like structure formed from the sol-gel synthesis and interact with the colorimetric agent present there, thus inducing a visible color change. Multiple techniques have been implemented in recent years to develop vapor sensors to detect common environmental hazards such as ammonia, benzene, or other vapors, and have been noted to be highly sensitive and/or efficient in the detection of their respective vapor analytes. For example, [PERSON] et al. developed a paper-based colorimetric sensor using methyl orange to detect trace levels of ammonia with a limit of detection at 2.0 ppbv[23]. Although not reusable, it was found to be superior to multiple other electrochemical and colorimetric sensors developed for ammonia. Additionally, [PERSON] et al. synthesized two novel solvatochromic dyes and affixed them to cotton fabrics to produce textile-based sensors that would detect multiple relevant solvents in the vapor phase [24]. Most notably, this sensor was found to be reusable for at least ten cycles with similar performance levels as the initial trial. Additionally, graphene-based [25], electrochemical [26], and semiconductor gas sensors [27, 28] are highly sensitive devices that have recently become more popular in the detection of vapor analytes. Nevertheless, for the purposes of our goal, a rapid colorimetric sensor with minimal complexity might better suit canine handlers so that it can be easily introduced into current canine training aid kits and can reduce potential end-user error. These visible color responses are crucial for correct interpretation of any analyses implementing colorimetric sensors and, unfortunately, they can be affected by a variety of environmental factors, such as interfering VOCs, pH, environment humidity, and temperature. Other colorimetric sensors have previously been noted to have a decrease in sensitivity at low target concentrations with the presence of moisture [29]. [PERSON] et al. studied the stability of their MDMA sol-gel colorimetric sensor for nearly three months and found that the sensor was stable at freezing temperatures with very minute deviations in the color intensity of their product [19]. Furthermore, they found that the sensor color darkened, and its responses started to vary slightly after being exposed to light for three hours. Similarly, [PERSON] and [PERSON] (2021) found that their paper-based colorimetric phosphate sensor was stable for 90 days at different temperatures ranging from 25 \({}^{\circ}\)C to 60 \({}^{\circ}\)C [30]. To confidently implement the proposed sensor in real-life applications, it was essential to study common factors that could affect the colorimetric response. This research developed and optimized the formulation for a paper-based vaporochromic sensor with a sol-gel coating infused with a colorimetric dye to detect cross-contamination of vapors. The sensor produces a colorimetric response when it comes into contact with the chosen target chemical agent in the vapor phase inside a closed container, such as a training aid kit. In testing the sensor application, this study evaluated the overall effects on the vaporochromic sensor when exposed to some environmental factors--such as temperature and light.