Ceilometer aerosol profiling versus Raman lidar in the frame of the INTERACT campaign of ACTRIS

Despite their differences from more advanced and more powerful lidars, the low construction and operation cost of ceilometers (originally designed for cloud base height monitoring) has fostered their use for the quantitative study of aerosol properties. The large number of ceilometers available worldwide represents a strong motivation to investigate both the extent to which they can be used to fill in the geographical gaps between advanced lidar stations and also how their continuous data flow can be linked to existing networks of the more advanced lidars, like EARLINET (European Aerosol Research Lidar Network). In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol properties through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking) campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60◦ N, 15.72◦ E), in the framework of the ACTRIS (Aerosol Clouds Trace gases Research InfraStructure) FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of 6 months. The comparison of the attenuated backscatter coefficient profiles from a multiwavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K) reveals differences due to the expected discrepancy in the signal to noise ratio (SNR) but also due to changes in the ambient temperature on the short and midterm stability of ceilometer calibration. Therefore, technological improvements are needed to move ceilometers towards operational use in the monitoring of atmospheric aerosols in the low and free tropospher

Ceilometer Aerosol Profiling versus Raman Lidar in the Frame of Interact Campaign of Actris

In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol properties through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking) campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60 N, 15.72 E), in the framework of ACTRIS (Aerosol Clouds Trace gases Research InfraStructure) FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of six month. The comparison of the attenuated backscatter coefficient profiles from a multi-wavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K) reveals differences due to the expected discrepancy in the SNR but also due to effect of changes in the ambient temperature on the stability of ceilometer calibration over short and mid-term. Technological improvements of ceilometers towards their operational use in the monitoring of the atmospheric aerosol in the low and free troposphere are likely needed

New Insights from Zinc and Copper Isotopic Compositions into the Sources of Atmospheric Particulate Matter from Two Major European Cities

This study reports spatial and temporal variability of Zn and Cu isotopes in atmospheric particulate matter (PM) collected in two major European cities with contrasting atmospheric pollution, Barcelona and London. We demonstrate that nontraditional stable isotopes identify source contributions of Zn and Cu and can play a major role in future air quality studies. In Barcelona, samples of fine PM were collected at street level at sites with variable traffic density. The isotopic signatures ranged between −0.13 ± 0.09 and −0.51 ± 0.05‰ for δ⁶⁶Zn_IRMM and between +0.04 ± 0.20 and +0.33 ± 0.15‰ for δ⁶⁵Cu_AE633. Copper isotope signatures similar to those of Cu sulfides and Cu/Sb ratios within the range typically found in brake wear suggest that nonexhaust emissions from vehicles are dominant. Negative Zn isotopic signatures characteristic for gaseous emissions from smelting and combustion and large enrichments of Zn and Cd suggest contribution from metallurgical industries. In London, samples of coarse PM collected on the top of a building over 18 months display isotope signatures ranging between +0.03 ± 0.04 and +0.49 ± 0.02‰ for δ⁶⁶Zn_IRMM and between +0.37 ± 0.17 and +0.97 ± 0.21‰ for δ⁶⁵Cu_AE633. Heavy Cu isotope signatures (up to +0.97 ± 0.21‰) and higher enrichments and Cu/Sb ratios during winter time indicate important contribution from fossil fuel combustion. The positive δ⁶⁶Zn_IRMM signatures are in good agreement with signatures characteristic for ore concentrates used for the production of tires and galvanized materials, suggesting nonexhaust emissions from vehicles as the main source of Zn pollution

Additional file 3: of Silica diatom shells tailored with Au nanoparticles enable sensitive analysis of molecules for biological, safety and environment applications

Fluorescence images of D24 systems. (DOCX 515 kb

Additional file 2: of Silica diatom shells tailored with Au nanoparticles enable sensitive analysis of molecules for biological, safety and environment applications

Notes on the diatomaceous earth used in this study. (DOCX 18 kb

Additional file 1: of Silica diatom shells tailored with Au nanoparticles enable sensitive analysis of molecules for biological, safety and environment applications

SEM images of D24 systems. (DOCX 878 kb

Additional file 4: of Silica diatom shells tailored with Au nanoparticles enable sensitive analysis of molecules for biological, safety and environment applications

Supporting figures to the Numerical Simulation Methods of the main text. (DOCX 608 kb