title: Day-night variability of water-soluble ions in PM10samples collected at a traffic site in southeastern Spain.
abstract: The present work reports diurnal and nocturnal concentrations of water-soluble ions associated to PM10samples collected during the warm and cold seasons in the urban center of Elche (Southeastern Spain). Statistical differences between daytime and nighttime levels of PM10were only observed during winter. The lower concentrations during the night were most likely the result of a reduction in traffic-induced road dust resuspension, since nocturnal concentrations of calcium also exhibited a significant decrease compared to daytime levels. During the warm season, nitrate was the only component that showed a statistically significant increase from day to night. The lower nocturnal temperatures that prevent the thermal decomposition of ammonium nitrate and the formation of nitric acid favored by the higher relative humidity at night are the most probable reasons for this variation. The close relationship between nitrate formation and relative humidity during nighttime was supported by the results of the correlation analysis. The reaction of sulfuric and nitric acids with CaCO3occurred to a greater extent during daytime in summer.
authors.affiliation: Atmospheric Pollution Laboratory (LCA), Department of Applied Physics, Miguel Hernández University, Avenida de la Universidad S/N, 03202, Elche, Spain. ngalindo@umh.es.
authors.forename: Nuria
authors.initials: N
authors.lastname: Galindo
authors.affiliation: Atmospheric Pollution Laboratory (LCA), Department of Applied Physics, Miguel Hernández University, Avenida de la Universidad S/N, 03202, Elche, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Yubero
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002119:Calcium Carbonate / Q000032:analysis; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D007477:Ions; D009566:Nitrates / Q000032:analysis; D017942:Nitric Acid / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D012995:Solubility; D013030:Spain; D013464:Sulfuric Acids / Q000032:analysis; D013696:Temperature; D014186:Transportation; D014867:Water / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D004391:Dust; D007477:Ions; D009566:Nitrates; D052638:Particulate Matter; D013464:Sulfuric Acids; D014867:Water; D017942:Nitric Acid; D002119:Calcium Carbonate; C033158:sulfuric acid; C006568:ammonium nitrate
keywords: Diurnal variation; PM10; Seasonal variation; Traffic; Water-soluble ions