Influence of Technological Housing Conditions on the Concentration of Airborne Dust in Dairy Farms in the Summer: A Case Study

SIMPLE SUMMARY: Due to modern housing systems and new barn concepts, an indoor environment on dairy farms has become very important. Airborne dust is a significant pollutant in the indoor environment of animal barns. An increased concentration of small airborne dust particles can cause health problems for farm animals and workers. This research shows that cattle barns with straw bedding cause more indoor airborne dust than barns without straw. Increased ventilation airflow has a positive effect on reducing the concentration of airborne dust particles, which was especially evident in the comparison of older, massive brick cowsheds compared to modern, light, uninsulated barns. The installation and operation of axial fans with a horizontal axis of rotation significantly help natural ventilation in terms of airborne dust concentration reduction. The results of the research showed that a large proportion of airborne dust particles in the summer are made up of the smallest dust particles. ABSTRACT: This research shows the size composition of airborne dust fractions in selected dairy barns down to the smallest particles, including factors that influence this composition. Measurements with a Dust-Track 8530 laser photometer took place in the summer at external temperatures of 29.5 to 36 °C. In barns with straw bedding, the average total dust concentration TDC was 66.98 ± 28.38 μg·m(−3) (PM(10) 60.11 ± 19.93 μg·m(−3), PM(4) 49.48 ± 13.76 μg·m(−3), PM(2.5) 44.78 ± 10.18 μg·m(−3), and PM(1) 38.43 ± 9.29 μg·m(−3)). In barns without straw bedding, the average TDC was 55.91 ± 36.6 μg·m(−3), PM(10) 33.71 ± 13.86 μg·m(−3), PM(4) 30.69 ± 15.29 μg·m(−3), PM(2.5) 27.02 ± 13.38 μg·m(−3), and PM(1) 22.93 ± 10.48 μg·m(−3). The largest TDC of 108.09 ± 32.93 μg·m(−3) (PM(10) 69.80 ± 18.70 μg·m(−3), PM(4) 68.20 ± 18.41 μg·m(−3), PM(2.5) 53.27 ± 14.73 μg·m(−3), and PM(1) 38.46 ± 5.55 μg·m(−3)) was measured in an old cowshed with stanchion housing for 113 cows, straw bedding, and ventilation through windows. In a modern cowshed for loose housing of 440 lactating cows without straw bedding, with natural ventilation and 24 axial fans, TDC was 53.62 ± 49.52 μg·m(−3), PM(10) 20.91 ± 5.24 μg·m(−3), PM(4) 17.11 ± 3.23 μg·m(−3), PM(2.5) 13.71 ± 0.92 μg·m(−3), and PM(1) 12.69 ± 2.82 μg·m(−3). In all investigated barns, a large proportion of airborne dust particles (54.38 ± 20.82% of TDC) consists of the smallest PM(1) dust particles (from 12.69 ± 2.82 μg·m(−3) to 48.48 ± 1.18 μg·m(−3)).