Acute health effects from exposure to indoor ultrafine particles—A randomized controlled crossover study among young mild asthmatics

Particulate matter is linked to adverse health effects, however, little is known about health effects of particles emitted from typical indoor sources. We examined acute health effects of short-term exposure to emissions from cooking and candles among asthmatics. In a randomized controlled double-blinded crossover study, 36 young non-smoking asthmatics attended three exposure sessions lasting 5 h: (a) air mixed with emissions from cooking (fine particle mass concentration): (PM_2.5: 96.1 μg/m³), (b) air mixed with emissions from candles (PM_2.5: 89.8 μg/m³), and c) clean filtered air (PM_2.5: 5.8 μg/m³). Health effects (spirometry, fractional exhaled Nitric Oxide [FeNO], nasal volume and self-reported symptoms) were evaluated before exposure start, then 5 and 24 h after. During exposures volatile organic compounds (VOCs), particle size distributions, number concentrations and optical properties were measured. Generally, no statistically significant changes were observed in spirometry, FeNO, or nasal volume comparing cooking and candle exposures to clean air. In males, nasal volume and FeNO decreased after exposure to cooking and candles, respectively. Participants reported additional and more pronounced symptoms during exposure to cooking and candles compared to clean air. The results indicate that emissions from cooking and candles exert mild inflammation in asthmatic males and decrease comfort among asthmatic males and females.     

净水器陶瓷滤芯研制

介绍了一种采用注浆成型工艺生产水净化用陶瓷滤芯的制备工艺方法。     

Dynamic behavior of indoor ultrafine particles (2.3‐64 nm) due to burning candles in a residence

A major source of human exposure to ultrafine particles is candle use. Candles produce ultrafine particles in the size range under 10 nm, with perhaps half of the particles less than 5 nm. For these small particles at typically high concentrations, coagulation and deposition are two dominant mechanisms in aerosol size dynamics. We present an updated coagulation model capable of characterizing the relative contributions of coagulation, deposition, and air exchange rates. Size‐resolved coagulation and decay rates are estimated for three types of candles. Number, area, and mass distributions are provided for 93 particle sizes from 2.33 to 64 nm. Total particle production was in the range of 10¹³ min^?1. Peak number, area, and mass concentrations occurred at particle sizes of <3, 20, and 40 nm, respectively. Both the number and area concentrations greatly exceeded background concentrations in the residence studied. Contributions of coagulation, deposition, and air exchange rates to particle losses were 65%, 34%, and 0.3% at high concentrations (10⁶ cm^?3), while they are 17%, 81%, and 1.7% at lower concentrations (3 × 10⁴ cm^?3), respectively. The increased particle production for the very smallest particles (2.33‐2.50 nm) suggests that even smaller particles may be important to study.     

Hydrogenated vegetable oils as candle wax

Partially hydrogenated soybean oil, referred to as soywax, is gaining attention as a renewable and biodegradable alternative to paraffin wax for use in candles. However, current soywax candles suffer from several problems, especially poor melting and solidification properties. Fully hydrogenated soybean oil exhibits improved melting properties but owing to its fragile texture, it is not yet acceptable in most candle applications. In the present work, KLX^TM (a wax composed of fractionated hydrogenated soy and cottonseed oils) was used as a base material for candles, and the effects of additives such as hydrogenated palm oil (HPO), FFA, and paraffin on the textural and combustion properties were evaluated. Melting and solidification profiles of KLX were better than those of fully hydrogenated soy oil. Adding FFA improved the solidification properties of KLX candles. Adding paraffin improved the compressibility of the wax, while HPO addition decreased hardness and compressibility. Changing the candle diameter and/or wick size along with changing the wax composition resulted in candles with desirable quality attributes.     

Pierre Thibault

At a time when little in architectural design seems like uncharted territory, Brian Carter, Professor and Dean of the School of Architecture and Planning at the University of Buffalo, The State University of New York, goes northeast to Quebec and encounters the work of architectural explorer Pierre Thibault. He describes how Thibault sets out to develop projects in some of the most ‘remote, expansive and sparsely settled’ areas of the region, responding afresh to the landscape and its indigenous culture. Copyright © 2009 John Wiley & Sons, Ltd.