A comparison of total, respirable, and real-time airborne particulate sampling in horse barns.

This research compares the concentration and distribution of different types of airborne particles in horse barns across summer and winter seasons. The findings suggest that these concentrations differ from barn to barn. It also indicates that more comprehensive real-time data, collected with an aerosol photometer, might be better to measure total airborne particles than just breathable particles.

Research Methodology

• The study was conducted in 12 different horse barns during the summer and winter seasons. This aims to capture the variance in environmental conditions and how it might affect airborne particle distribution.
• Three types of airborne particles were measured – total particulate (TP), respirable particulate (RP), and real-time particulate (RTP).
• TP and RP concentrations were measured gravimetrically – a method that involves weighing – to establish a physical sense of the tangible air particles present. On the other hand, RTP – which represents the particles present at any given time – was captured using an aerosol photometer. This device measures light scattered by particles from a light source, providing an immediate measure of airborne particles.

Major Findings

• There was a marked variance in the concentrations of the different types of particles. TP ranged from non-detectable to 2.1 mg/m3 in winter and up to 1.2 mg/m3 in summer. Meanwhile, RP ranged from non-detectable to 0.2 mg/m3 in winter and up to 0.7 mg/m3 in summer.
• The study found that the average fraction of RP was notably higher in the summer compared to winter, with a mean of 0.63 and 0.34 respectively.
• Moreover, the RTP concentration showed a significant correlation with the TP measurements during the winter and when considering pooled data from both seasons. However, the RTP did not correlate significantly with RP whether it was in winter, summer, or pooled data.
• The peak RTP levels, averaged over 10-second intervals, were estimated to rise to 22 mg/m3.

Implications of the Study

• The research provides evidence of the variation in airborne particulate concentrations and particle size distributions among different horse barns. This reinforces the idea that each individual environment can have its unique particle distribution.
• The findings also suggest that using real-time sampling with an aerosol photometer could provide a more reliable measure of TP in these specific environments – something that could be more informative than just measuring respirable particles.