Exposure to airborne allergens from mice and rats can lead to laboratory animal asthma or allergy. Several biological methods can measure allergens contained in aerosols; however, they are time and cost intensive. An innovative methodology is proposed to warn laboratory animal facility workers of a possible rise in mouse and rat allergens by measuring the relationships between airborne allergens, particulate matter (PM), and volatile organic compounds (VOCs). By using a low-cost sensor (average

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... difference respect to reference methods of 3 and 9% for PM 2.5 and VOC, respectively), Spearman's rank correlation between allergens and time-averaged PM and VOCs was found to be 0.3 and − 0.07, respectively. These numbers indicate a poor correlation between allergens and PM 2.5 and VOC; however, by considering only the spikes in PM minute-by-minute data, the relation between time-average PM and allergens increases up to 0.71. This high value indicates the applicability of PM low-cost sensors in laboratory animal centers as a warning sign of raising values of allergens. Mouse and rat allergens are present in the animals' urine, which can become aerosolized during animal activity, or task activities carried out in the laboratory facility. While previous references established a correlation between activities and mouse and rat allergens, the results are outdated and refer to a limited number of activities. For example, washing lab coats, changing uniforms, sitting in an office space, having lunch, or walking in any corridor are shown in this study to contain on average 1.77, 0.96, 0.65, 0.88, and 1.62 ng/m 3 of rat allergens, respectively. Thus, locations that do not contain any direct source of allergens are positive to the presence of mouse and rat allergens.