Background: The study aimed to evaluate the effectiveness of filtering facepiece respirators (FFRs) in reducing odour nuisances in agricultural work environment. Additionally, an assessment was conducted on the microbiological contamination of FFRs and the functionality of Time4Mask application in enhancing workplace safety. Material and Methods: Two types of FFRs were used for the study: with absorbing properties and reference ones. The research was carried out in 6 livestock rooms during a 1-week period in early spring (February–March 2021) on a farm in central Poland. The microclimate conditions (thermoanemometer), and particulate matter concentrations (laser photometer) were assessed. Additionally, the odour content in the studied rooms and the breathing zone of FFR users (gas chromatography with mass spectrometry) were evaluated. The number of microorganisms on the respirators was determined (cultivation method), followed by their identification (biochemical tests, taxonomic keys). Breakthrough curves were determined for both FFR types to assess absorption capabilities. Results: The average temperature in the livestock rooms was about 13°C, relative humidity – 53%, air flow velocity – 0.21 m/s, and particulate matter concentration – 0.216 mg/m³. A significant variety of odorants was found in the environment and the breathing zone under the FFRs. Bacterial counts ranged between 2.4 × 10¹ and 2.6 × 10² CFU/cm², fungi between 3.2 × 10⁰ and 5.4 × 10¹ CFU/cm², xerophilic fungi from 4.4 × 10⁰ to 4.0 × 10¹ CFU/cm², mannitol-positive staphylococci between 1.6 × 10¹ and 1.0 × 10² CFU/cm², and haemolytic staphylococci from 2.2 × 10¹ to 4.5 × 10¹ CFU/cm², depending on the respirator type. Respirators were colonized by bacteria from the genera: Bacillus, Staphylococcus, actinobacteria Streptomyces sp., and fungi: Candida, Absidia, Aspergillus, Mucor, and Penicillium. Respirators with absorbing properties had over 8-times longer breakthrough time than reference ones. Conclusions: Respirators with activated carbon effectively improved work comfort when exposed to odours. Due to growth of microorganisms in the respirator materials, periodic replacement is necessary. It is crucial to provide workers with information about the safe-use time of respirators, considering environmental conditions. This is achievable using modern IT tools like Time4Mask application. Med Pr Work Health Saf. 2023;76(5):363–75.