Metals, nonmetals and metalloids in cigarette smoke as hazardous compounds for human health.

Cigarette smoke contains many chemicals that are harmful to both smokers and non-smokers. Breathing just a little cigarette smoke can be harmful. There are >7000 chemicals in cigarette smoke, at least 250 are known to be harmful and many of them can cause cancer. Currently, many studies reported the types of harmful organic compounds in cigarette smoke; instead, there are almost no works that describe the presence of inorganic compounds. In this work, a cost-effective self-made passive sampler (SMPS) was tested as a tool to collect different types of particulate matter (PM) from cigarette smoke containing metals as hazardous compounds (HCs). To determine the nature of the metals, nonmetals and metalloids as HCs, a direct qualitative analysis of the particulate matter (PM) was conducted without developing any special sample preparation procedure. For that, non-invasive elemental (Scanning Electron Microscope coupled to Energy Dispersive X-ray Spectrometry) and molecular (Raman microscopy) micro-spectroscopic techniques were used. Thanks to this methodology, it was possible to determine in deposited PM, the presence of metals such as Fe, Cr, Ni, Ti, Co, Sn, Zn, Ba, Al, Cu, Zr, Ce, Bi, etc. most of them as oxides but also embedded in different clusters with sulfates, aluminosilicates, even phosphates.

PM10 spatial distribution and metals speciation study in the Bilbao metropolitan area during the 2017-2018 period.

Speciation of respirable particles is becoming increasingly important from an epidemiological and analytical point of view to determine the potential effects of air pollution on human health. For this reason, current laws and analytical sampling methods focus on particle size, as it turns out to be the main factor for the greater or lesser penetration into the airways. In this sense, particles of less than 10 µm in diameter (<10 µm), referred to as PM10, are the particles that have a higher capacity for access to the respiratory tract and, therefore, more significant effect on them. In this sense, one of the most important factors that have a key role in the PM10 atmospheric pollution effect is the dispersion effect with the direct influence of natural effects such as wind, rain, topography apart from others. In this work, PM10 data extracted from the Basque Government environmental stations (19 sampling points) in the Biscay province (Basque Country, north of Spain) were combined with the results obtained from the use of self-made passive samplers (SMPS) in the same sampling points areas and subsequently, the sample analysis with a non-invasive elemental technique (Scanning Electron Microscope coupled to Energy Dispersive X-ray Spectrometry) was carried out. Thanks to this methodology, it was possible to determine a wide variety of metals in PM10 such as Al, Fe, Cr, Ni, Pb, Zn, Ti, etc. Most of them present as oxides and others as part of natural aggregations such as quartz, aluminosilicates, phosphates etc.

Packaging to prolong shelf life of preservative-free white bread.

This research studied various types of packaging to prolong the shelf life of non-preservative white bread. Three types of blown film packages were used, i.e. a single LDPE layer incorporated with an oxygen scavenger, a single LDPE layer containing an oxygen absorber sachet, and three layers of LDPE laminated with O-nylon. The effects of modified packaging atmosphere, i.e. 5, 10, and 21 vol. % of oxygen in nitrogen balance, on the shelf life was also included. Characterization of the packaging films was carried out using several techniques, such as Oxygen Transmission Rate (OTR) and an optical microscopy. Headspace gases, microbial count, as well as physical appearance were used to evaluate the shelf life. The optical microscopic images showed that incorporating the oxygen scavenger into the plastic film produced small pores, contributing to a passive function of the films as their OTRs were significantly enhanced. However, the microbial growth on bread stored in those packages was suppressed, implying that the intermediate generated from scavenging reaction might act as a fungistatic. Even though the scavenging capability of the oxygen absorber sachet lasted only for 4 days, the fungi and mould development thereafter was still lower compared to the package without the sachet. The prolonging white bread shelf life was found to be primarily dependent on two factors. The package with a high oxygen barrier such three-layer films defeated microorganisms. With a low initial oxygen level of around 5% by volume, the bread shelf life could be prolonged up to 5-7 days.