Résultats de la mesure de la concentration en poussière dans l'air de 12 porcheries

Aerial dust concentrations in 12 pig houses Dust concentration was measured during 3 days at hourly intervals in 5 farrowing houses and 7 fattening houses. The number concentration of aerial particles was measured using a counter which sizes the total numbers in 5 categories: from 0.3-0.5 mum to > 5 mum.
The mean dust concentrations were significantly higher in the farrowing houses than in the fattening houses (179 +/- 91 vs 97 +/- 65 particles/ml). Over a 24-h period, the ratio between the highest and the lowest hourly concentrations was 3 +/- 1 in the farrowing houses and 5 +/- 4 in the fattening houses; the difference between the 2 types of houses is significant. The smallest particles were the most numerous; 82 % of the aerial particles were in the size range 0.3-0.5 mum, with less than 1 % being 5 mum or larger. During the most polluted hours, there was proportionally more particles in the size range 0.5-1 mum and significantly less particles in the size ranges 1-2 mum and 2-5 mum, as compared to the less polluted hours.
This study shows that most of the aerial particles in piggeries are smaller than 5 mum, the size below which deposition is regarded to occur in the lower respiratory tract, the farrowing houses being more polluted than the fattening houses.