Platinum concentration in PM2.5 in the Mexico City Metropolitan Area: relationship to meteorological conditions

AbstractPlatinum (Pt) concentrations in PM2.5 were evaluated by means of inductively coupled plasma mass spectrometry (ICP-MS) to evaluate the spatial and temporal behavior and to assess trends. Samples were taken from five representative sites in the Mexico City Metropolitan Area (MCMA): Tlalnepantla-northwest (NW), San Agustin-northeast (NE), La Merced -center (C), Coyoacan-southwest (SW), and Universidad Autonoma Metropolitana Iztapalapa-southeast (SE). Under three weather conditions: dry warm (DW-April), rainy (R-August), and dry cold (DC-November) in 2013. We found that the PM2.5 median mass concentration was 24 μg m−3 ± 15 μg m−3 while Pt concentration was 55 pg m−3 ± 15 pg m−3 (median, interquartile range). Seasonal trend was identified: the concentrations decreased significantly in the following order DC > R>DW. No spatial distribution was observed. Interestingly, among other meteorically parameters, wind intensity resulted to be the major factor for the dispersion of Pt in PM2.5 in MCMA. Furtherm...