Vapours

About: Vapours is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 15022 citations.

The combined effect of exposures to vapours, gases, dusts, fumes and tobacco smoke on current asthma

Abstract: Smoking, exposure to environmental tobacco smoke (ETS) and occupational exposure to vapours, gases, dusts or fumes (VGDF) increase asthma symptoms. The impact of combined exposure is less well established. We aimed to evaluate the risk of combined exposure to smoking, ETS and VGDF on the prevalence of current asthma and asthma‐related symptoms with a postal survey among a random population of 16,000 adults, aged 20–69 years (response rate 51.5%). The 836 responders with physician‐diagnosed asthma were included in the analysis. Of them, 81.9% had current asthma defined as physician‐diagnosed asthma with current asthma medication use or reported symptoms. There was a consistently increasing trend in the prevalence of current asthma by increased exposure. The highest prevalence of multiple symptoms was in smokers with VGDF exposure (92.1%) compared to the unexposed (73.9%, p = 0.001). In logistic regression analysis, combined exposure to several exposures increased the risk in all analysed symptoms (p = 0.002–0.007). In conclusion, smoking and exposure to ETS or VGDF increased the prevalence of current asthma and multiple symptoms. The combined exposure carried the highest risk. Preventive strategies are called for to mitigate exposure to tobacco smoke and VGDF.

Process and apparatus for enriching and purifying aqueous hydrogen peroxide solutions

Abstract: The invention relates to a process and an apparatus for producing enriched, purified aqueous hydrogen peroxide solutions, by means of which it is possible to obtain high-purity hydrogen peroxide solutions which are also suitable, in particular, for use in the electronics industry. The apparatus comprises: (I) a vaporisation device (2) for vaporising the crude hydrogen peroxide solutions to give vapours containing liquid in the form of a liquid mist, (II) a gas-liquid separation device (4) for separating the vapours from the liquid mist and (III) a distillation column (6) for the fractional distillation of the vapours freed of the liquid mist. It is characterised in that the gas-liquid separation device (4) comprises at least two and preferably two or three cyclones (26, 28, 30) connected in series. The connection in series of the cyclones (26, 28, 30) gives a highly effective separation of the liquid mist from the vapours which are then concentrated by being subjected to the fractional distillation. Even if only two cyclones are used, the concept of the invention leads to high-purity H2O2 solutions of a quality which was not obtainable according to the prior art, since the H2O2 solutions have considerably reduced contents of impurities.