This review surveys mitigation strategies for air pollutants in mechanically ventilated livestock and poultry housing, covering ammonia, particulate matter and the ventilation measures used to manage them. That is the subject matter it is worth consulting for. Its treatment of air filtration for disease control is brief and is carried second hand from other studies.
The filtration paragraph illustrates why secondary summaries need checking against sources. It compresses findings from the Alonso 2013 work in a way that inverts one of them, presenting a modelling input as if it were an economic result the study produced. Because the two halves of that sentence come from the same paraphrase, neither half can be relied upon, and nothing from it is reproduced here. The verified figures live in the primary papers: an approximately 80 percent reduction in the risk of novel PRRSV introduction from the epidemiological study in Preventive Veterinary Medicine 112, and payback periods of 2.1 years at 150 dollars per sow and 2.8 years at 200 dollars per sow from the financial companion in volume 111. Figures the review attributes to Wenke and colleagues in 2018 are likewise carried second hand and are not restated here; the verified results from that paper are its dust concentration and lung health findings.
The practical lesson generalises beyond this one review. Numbers travel through the industry literature faster than the papers they came from, and a citation chain that runs review to review can invert an input into an output without any step in the chain looking wrong. For any figure that will be used to justify a capital decision, the primary source is the only reliable stopping point.