The effect of salting with magnesium chloride on the concentration of particular matter in a road tunnel

• Published in: Atmospheric environment (1994) Vol. 42; no. 8; pp. 1762 - 1776
• Main Authors: Aldrin, Magne, Hobæk Haff, Ingrid, Rosland, Pål
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.2008; Elsevier Science
• Subjects: Air quality modelling; Applied sciences; Atmospheric pollution; Dust treatment; Exact sciences and technology; Generalised additive models; Pollution; Prevention and purification methods; Road dust; Transports and other; Urban air quality; Norway; Europe; Urban air quality; Generalised additive models; Air quality modelling; Road dust; Dust treatment; Pollution prevention; Magnesium chloride; Air quality; Urban area; Modeling; Coarse particle; Dust; Road tunnel; Particle resuspension; Fine particle; Aerosols; Air pollution
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2007.11.024

This work presents an analysis of the effect of dust treatment with a magnesium chloride solution on the concentration of airborne particulate matter inside a road tunnel. During the winter 2004/2005, the road inside the tunnel of Strømsås was salted 43 times with magnesium chloride solution, of which 27 times with the amount 20 g m - 2 and 16 with 40 g m - 2 . In addition, the road was swept 11 times and washed twice. Simultaneously, one recorded the concentration of PM 10 and PM 2.5 hourly. The model used in the analysis is a generalised additive model (GAM) on log-scale, having traffic counts, diverse meteorological conditions and the pollution reducing actions as predictor variables. The analysis revealed no clear effect from sweeping and washing. The impact of the dust binding medium on the concentrations of particulate matter is, however, clearly propitious. As one would expect, it is largest immediately after applying the magnesium chloride, and diminishes steadily afterwards. The duration of the effect is estimated to 10 days, but with a rather large uncertainty (95% confidence intervals between 3 and 16 days). We estimated an effect (reduced pollution level) of 70 % on the concentration of the coarse particles PM 10 – PM 2.5 and 56 % on the concentration of PM 10 . The estimated effect on the fine particles PM 2.5 is a modest 17 % , and barely significant.