Effect of platform subway depth on the presence of Airborne PM, metals, and toxic organic species.

PM that have been related to public health risks, were collected during two seasons with High-Vol samplers in platforms of a Mexican subway station, which interconnects through transfers three lines having different depths. The objective was to study the influence of depth on the PM concentrations and their species. PM concentrations in cold-dry and warm-dry seasons presented statistical differences, being in average 57 and 66 μgm respectively, in the shallower line 9; 90 μgm and 111 μgm in line 1; and 104 and 122 μgmin the deepest line 7.

Emission factors of atmospheric and climatic pollutants from crop residues burning.

Unlabelled: Biomass burning is a common agricultural practice, because it allows elimination of postharvesting residues; nevertheless, it involves an inefficient combustion process that generates atmospheric pollutants emission, which has implications on health and climate change. This work focuses on the estimation of emission factors (EFs) of PM, PM, organic carbon (OC), elemental carbon (EC), carbon monoxide (CO), carbon dioxide (CO), and methane (CH) of residues from burning alfalfa, barley, beans, cotton, maize, rice, sorghum, and wheat in Mexico. Chemical characteristics of the residues were determined to establish their relationship with EFs, as well as with the modified combustion efficiency (MCE).

Effect of Zirconia Nanoparticles in Epoxy-Silica Hybrid Adhesives to Join Aluminum Substrates.

This research presents the interaction of the epoxy polymer diglicydil ether of bisphenol-A (DGEBA) with silica (SiO₂) nanoparticles plus zirconia (ZrO₂) nanoparticles obtained via the sol-gel method in the synthesis of an epoxy-silica-zirconia hybrid adhesive cured with polyamide. ZrO₂ nanoparticles were added to the epoxy-silica hybrid adhesive produced in situ to modify the apparent shear strength of two adhesively bonded aluminum specimens. The results showed that the addition of different amounts of ZrO₂ nanoparticles increased the shear strength of the adhesively bonded aluminum joint, previously treated by sandblasting, immersion in hot water and silanized with a solution of hydrolyzed 3-glycidoxipropyltrimethoxysilane (GPTMS).

Emissions of PAHs derived from sugarcane burning and processing in Chiapas and Morelos México.

Sugarcane burning is an agricultural practice implemented to ease farm worker duties; nevertheless, as a consequence, tons of particles are emitted to the atmosphere. Additionally, during harvesting the sugar-mills operate the whole day emitting hundreds of tons of pollutants. Therefore, health risks to neighboring population should be a major governmental concern, leading first to identification and quantification of toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs).