Article

Characterization of Aerosols Containing Zn, Pb, and Cl from an Industrial Region of Mexico City

Department of Chemistry and Biochemistry, University of California, San Diego, California 92093-0314, USA.
Environmental Science and Technology (Impact Factor: 5.48). 11/2008; 42(19):7091-7. DOI: 10.1021/es7030483
Source: PubMed

ABSTRACT Recent ice core measurements show lead concentrations increasing since 1970, suggesting new nonautomobile-related sources of Pb are becoming important worldwide (1). Developing a full understanding of the major sources of Pb and other metals is critical to controlling these emissions. During the March, 2006 MILAGRO campaign, single particle measurements in Mexico City revealed the frequent appearance of particles internally mixed with Zn, Pb, Cl, and P. Pb concentrations were as high as 1.14 microg/m3 in PM10 and 0.76 microg/m3 in PM2.5. Real time measurements were used to select time periods of interest to perform offline analysis to obtain detailed aerosol speciation. Many Zn-rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2 x 6H2O. The internally mixed Pb-Zn-Cl particles represented as much as 73% of the fine mode particles (by number) in the morning hours between 2-5 am. The Pb-Zn-Cl particles were primarily in the submicrometer size range and typically mixed with elemental carbon suggesting a combustion source. The unique single particle chemical associations measured in this study closely match signatures indicative of waste incineration. Our findings also show these industrial emissions play an important role in heterogeneous processing of NO(y) species. Primary emissions of metal and sodium chloride particles emitted by the same source underwent heterogeneous transformations into nitrate particles as soon as photochemical production of nitric acid began each day at approximately 7 am.

Download full-text

Full-text

Available from: Vaithiyalingam Shutthanandan, Jul 07, 2015
0 Followers
 · 
168 Views
  • Source
    • "ed in CA ( Fig . 3 ) , it is evident that the strong association between Ni and V exists in all fractions . The Ni – V associations in the fine and the accumulation mode and in the fraction PM 1 . 5 – 3 . 0 of coarse mode are in the group of elements of primary anthropogenic origin that could be combustion of fossil fuels ( Suarez and Ondov 2002 ; Moffet et al . 2008 ) . Associations of Ni – V present - ed in fractions of PM 3 . 0 – 7 . 2 and PM >7 . 2 are in the clusters of elements representing the resuspension ( Fig . 3 ) . Their strong associations in the fine and the accumulation mode as well as fraction PM 1 . 5 – 3 . 0 of coarse mode indi - cate their common origin from primary anthropogenic "
    [Show abstract] [Hide abstract]
    ABSTRACT: Size segregated particulate samples of atmospheric aerosols in urban site of continental part of Balkans were collected during 6 months in 2008. Six stages impactor in the size ranges: Dp ≤ 0.49 μm, 0.49 < Dp ≤ 0.95 μm, 0.95 < Dp ≤ 1.5 μm, 1.5 < Dp ≤ 3.0 μm, 3.0 < Dp ≤ 7.2 μm, and 7.2 < Dp ≤ 10.0 μm was applied for sampling. ICP-MS was used to quantify elements: Al, As, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, K, Li, Na, Ni, Mg, Mn, Pb, Sb, V, and Zn. Two main groups of elements were investigated: (1) K, V, Ni, Zn, Pb, As, and Cd with high domination in nuclei mode indicating the combustion processes as a dominant sources and (2) Al, Fe, Ca, Mg, Na, Cr, Ga, Co, and Li in coarse mode indicating mechanical processes as their main origin. The strictly crustal origin is for Mg, Fe, Ca, and Co while for As, Cd, K, V, Ni, Cu, Pb, and Zn dominates the anthropogenic influence. The PCA analysis has shown that main contribution is of resuspension (PC1, σ(2) ≈ 30 %) followed by traffic (PC2, σ(2) ≈ 20 %) that are together contributing around 50 % of elements in the investigated urban aerosol. The EF model shows that major origin of Cd, K, V, Ni, Cu, Pb, Zn, and As in the fine mode is from the anthropogenic sources while increase of their contents in the coarse particles indicates their deposition from the atmosphere and soil contamination. This approach is useful for the assessment of the local resuspension influence on element's contents in the aerosol and also for the evaluation of the historical pollution of soil caused by deposition of metals from the atmosphere.
    Environmental Science and Pollution Research 05/2014; 21(18). DOI:10.1007/s11356-014-2998-1 · 2.76 Impact Factor
  • Source
    • "To our knowledge, there are no publications concerning the interfacial chemistry between CaCO 3 and ZnSO 4 particles. Previous work has demonstrated the usefulness of Raman microspectrometry for investigating heterogeneous reaction mechanisms which occur between aggregated atmospheric particles (Jentzsch et al., 2012; Moffet et al., 2008; Sobanska et al., 2012; Falgayrac et al., 2006; Ishizaka et al., 2009). These experiments, performed either for particles deposited on substrates or levitated particles, highlight the significant role of water, ubiquitous in the troposphere where several wetedry cycles occur. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Laboratory experiments using Raman imaging demonstrated the behaviour of ZnSO4·7H2O (goslarite) microparticles in contact with a {101¯4} CaCO3 (calcite) surface under three different experimental conditions representative of remote atmosphere. Contact between the ZnSO4·7H2O particles and the CaCO3 surface in humid air (RH ∼40–80%) did not induce any deliquescence and chemical phenomena. In contrast, condensation of a water drop at the ZnSO4·7H2O–CaCO3 interface caused free dissolution of the ZnSO4·7H2O particle and rapid precipitation of Zn4SO4(OH)6 onto the CaCO3 surface. This coating inhibited the surface reaction and subsequent drying resulted in the deposition of residual ZnSO4·7H2O, then ZnSO4·H2O (gunningite) and CaSO4·2H2O (gypsum) superimposed onto the Zn4SO4(OH)6 layer. The deposition of ZnSO4·7H2O particles in a water drop, previously in contact with a CaCO3 particle for a long time, resulted in the coprecipitation of Zn4SO4(OH)6 and Zn5(CO3)2(OH)6 (hydrozincite). Subsequent drying caused the deposition of residual ZnSO4·7H2O, ZnSO4·H2O and CaSO4·2H2O as small particles. These results indicated the possible fates of ZnSO4 particles in a humid atmosphere, when externally mixed with CaCO3 mineral dust after atmospheric events such as aggregation, water condensation and evaporation. This study indicated the fundamental role of water that typically existed on the surface of aerosol particles in the troposphere. These heterogeneous chemical processes have substantial consequences on particle size and solubility, and thus on bioavailability and toxicity of metal-rich particles.
    Atmospheric Environment 03/2014; 85:83–91. DOI:10.1016/j.atmosenv.2013.11.073 · 3.06 Impact Factor
  • Source
    • "Atmospheric contamination by airborne particles (PM) enriched with metals has increased in regions with intense industrial activity (Douay et al., 2008; Perrone et al., 2010; Polichetti et al., 2009; Pruvot et al., 2006) and different megalopoleis in the world, particularly in Asia, Africa, and Latin America (Moffet et al., 2008; Park and Dam, 2010; Sammut et al., 2010; Shi et al., 2012; Waheed et al., 2011). Health risks associated with these atmospheric contaminations may arise mainly from inhalation of particles and consumption of polluted vegetables (Morman and Plumlee, 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO4, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO3. In rye-grass, the changes in Pb speciation were even more egregious: Pb-cell wall and Pb-organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better assess the health risks involved.
    Science of The Total Environment 02/2014; 476-477C:667-676. DOI:10.1016/j.scitotenv.2013.12.089 · 4.10 Impact Factor