Associations of barn air quality parameters with ultrasonographic lung lesions, airway inflammation and infection in group-housed calves.

Barn climate is believed to play a major role in the bovine respiratory disease complex. However, the exact air quality parameters associated with (sub)clinical pneumonia or airway inflammation in calves are currently unknown. The objective of this cross-sectional study was to assess associations of air quality parameters with clinical signs, lung consolidation, pulmonary inflammation and infection in group-housed calves. In total, 60 beef and dairy farms were visited from January to April 2017 and 428 calves sampled. Measured air quality parameters included continuous 24-h measurements of ammonia concentration, relative humidity and temperature and punctual measurements of air velocity, ammonia, CO2 and bacterial air load. Calf sampling consisted of clinical examination, thoracic ultrasonography and broncho-alveolar lavage sampling for bacteriological and cytological analysis of broncho-alveolar lavage fluid (BALf). Average air temperature was 14.2 °C (standard deviation (SD) 4.4, range 5.5-23.9) and relative humidity 68.8 % (SD 8.9, range 52.2-91.6). Average ammonia concentration was 1.7 ppm (SD 0.9, range 0-10.0). Lung consolidations of ≥1 cm, ≥3 cm and ≥6 cm in depth were present in 41.1 % (176/428), 27.1 % (116/428) and 16.1 % (69/428) of the calves, respectively. Average pen temperature was positively associated with consolidations of ≥1 cm (P = 0.005), ≥3 cm (P = 0.002) and ≥6 cm (P < 0.01). Ammonia exposure, in hours>4 ppm, was associated with lung consolidation ≥1 cm (odds ratio (OR) = 1.73; confidence interval (CI) = 1.02-3.07; P = 0.04). Ammonia concentration was positively associated with BALf epithelial cell percentage (P = 0.01). Air velocity >0.8 m/s was associated with increased odds of lung consolidation of ≥3 cm (OR = 6.8; CI = 1.2-38.5; P = 0.04) and ≥6 cm (OR = 15.9; CI = 1.2-200.0; P = 0.03). The prevalence of lung consolidations ≥1 cm was higher in the draught (81.8 %; P = 0.0092) and warm, dry and ammonia accumulation clusters (54.2 %; P = 0.02) compared to the presumably normal cluster (31.6 %). In addition, in the warm, dry and ammonia cluster the prevalence of lung consolidations ≥3 cm (38.1 %; P = 0.04) and ≥6 cm (31.4 %; P = 0.01) in depth were higher compared to the presumably normal climate cluster (18.2 % and 9.1 %, respectively). Of all frequently measured indoor air quality parameters, only average temperature, ammonia concentration and air velocity were associated with pneumonia and might therefore be preferable for cost-effective evaluation of calf barn climate.

A comparison of the performance of samplers for respirable dust in workplaces and laboratory analysis for respirable quartz.

The divergent sampling techniques for respirable dust and the analyses for crystalline silica are an important area of interest and discussion among industrial occupational hygienists in Europe. The variety of equipment for air sampling, methods and instrumentation can cause differences between results for the analysis of respirable crystalline silica (RCS). In this study, a Workplace Atmosphere Multi-sampler (WAM), developed by Adhesia, was used to compare respirable dust samplers in the workplace. This rotating device enables the comparison of 12 samplers in a workplace in each run. Seven laboratories participated in the comparison, using six different respirable dust samplers [British Cast Iron Research Association (BCIRA) to the Higgins Dewell (HD) design, Dorr Oliver, Casella SIMPEDS, SKC HD with a polycarbonate filter and polyvinylchloride filter, and the CIP10-R). Each laboratory analysed samples supplied by the samplers and reported the total respirable dust concentration and the RCS concentration. The techniques used were X-ray diffraction direct-on-filter, X-ray diffraction with deposition, infrared direct-on-filter, and infrared with potassium bromide (KBr) discs. The experiments were carried out in four different industries (enamel, sand extraction, foundry and brickworks). Generally, the SKC conductive black plastic sampler is oversampled (y = 1.52x + 0.008) and the CIP10 is undersampled (y = 0.74x + 0.068) when compared with the median air concentration. A pair-wise comparison of the different industries using t-tests indicated significant differences (P < 0.05) between the SKC conductive plastic samplers and the other samplers. The same series of statistical calculations were performed for the results obtained for RCS (quartz) and showed significant differences for the CIP10 techniques and the SKC conductive plastic cyclone analyses when using a polyvinylchloride filter.