Effects of Indoor Environmental Factors and House Structures on Vaporization of Active Ingredient from Spatial Repellent Devices in Rural Houses in Malawi.

Air-cleaning systems using a low concentration of chlorine dioxide (ClO2) gas for prevention against infection by the influenza virus have been developed. ClO2 gas is easily decomposed by indoor climate factors. Three experiments were conducted to evaluate the effects of indoor environmental factors on the decrease of ClO2 gas concentration. The reaction (decay) rate constant was also determined. High air temperatures and light irradiation accelerated the decrease of ClO2 gas concentration; the latter had the greatest influence on the decrease of ClO2 gas concentration among the conditions. A quicker decay of concentration and greater value of the reaction rate constant of ClO2 was found when a UV lamp was used; this is because the gas absorbs irradiation in the UV range. ClO2 gas concentration was significantly reduced when an evaporative humidifier was employed due to adsorption and a chemical reaction between the gas and the filter in the humidifier.

Seasonality of asthma may result from varying exposures. This cross-sectional study was designed to examine the relationship between indoor environmental factors and seasonal childhood asthma. Study subjects were participants from the International Study of Asthma and Allergies in Childhood (ISAAC) in 2004, a population-based surveillance, which included school children aged 6-15 yr in south Taiwan. Cases included 1725 children who experienced asthma symptoms in the past 12 months and the references consisted of 19,646 children who reportedly have no asthma history. By using a moving average and principal component analysis, asthmatic children were grouped into four asthma subtypes: winter, spring, summer/fall, and perennial. Multivariate logistic regression was used to evaluate the effect of indoor environmental factors on seasonality of childhood asthma. For all asthma prevalence, a peak occurred in the winter and a nadir appeared in summer. Contributing factors of asthma for children, regardless of seasonality, included younger age, parental atopy, maternal smoking during pregnancy, breast feeding, and perceived air pollution. After adjusted for salient risk factors, water damage was significantly associated with all subtypes of asthma. Presence of cockroaches was related to the summer/fall asthma (adjusted odds ratio [aOR] = 1.65, 95% confidence interval [CI] = 1.12-2.55). Visible mold on the walls was associated with an increased occurrence of winter and spring asthma (aOR = 1.53, 95% CI = 1.26-1.85 and aOR = 1.34, 95% CI = 1.10-1.62, respectively). Passive smoking was shown to be related to spring and summer/fall asthma. Water damage is a possible risk for childhood asthma year-round. Cockroaches and visible mold on the walls may play essential roles for seasonality of childhood asthma in Taiwan. Plausible mechanisms and allergic effects should be further determined. Elimination of these allergens is necessary to help prevent the development of asthma.

The relationships between indoor environment factors and signs of eye irritation were studied in a sample of female personnel with (n = 112) and without (n = 64) mucous membrane symptoms working in 36 nursing departments at geriatric hospitals in the municipality of Trondheim, Norway. The indoor climate was characterised by high room temperature (interquartile range 23.0-23.7 degrees C), low relative air humidity (interquartile range 17-26%) and high outdoor airflow rate, as indicated by low indoor levels of carbon dioxide (interquartile range 490-650 ppm). An altered microbial flora was observed in nine of the departments, and Aspergillus fumigatus was found in three of these. Five of the hospitals were situated in urban parts of the municipality near roads with heavy traffic. In the initial analyses decreased tear-film stability (BUT) was observed in subjects working in departments with increased dust settlement rate (P = 0.03), in hospitals situated in urban areas with heavy traffic (P < 0.001), and in subjects working in departments with presence of A. fumigatus (P = 0.04). Increased conjunctival staining (CS) was related to alteration of the microbial flora. In the final multivariate analyses statistically significant relationships were observed between BUT and dust settlement rate and urban vicinity of workplace and between CS and alteration of the microbial flora.

Among a variety of environmental factors, operative temperature, relative humidity and ventilation rate are generally considered to be factors that significantly affect work performance, and the interactions among these three factors were quantitatively studied in this paper. Eighteen participants were recruited to complete the neurobehavioral ability tests in different environments by central composite design, and their performance was analysed by regression fitting and multi-factor coupling analysis. By defining the interval coefficient β, the interaction effects between the factors were calculated quantitatively. The results showed that: for the performance of perception and expression tasks, there was an antagonistic effect between operative temperature and relative humidity (β = 0.50 ∼ 0.82), between operative temperature and ventilation rate (β = −0.29 to −0.38), and among the three factors (β = 0.38–0.67). There was a synergy effect between relative humidity and ventilation rate (β = 1.71–2.28). For the performance of reasoning tasks, the interaction effect among the three factors and their combinations is antagonistic effect (β = 0.67–0.83). Practitioner summary: We proposed a method to calculate the quantitative relation of multi-factor interactions. In recent ergonomics studies, more and more factors have been included. This method can well describe the synergistic or antagonistic effect of the changes of other factors on the target factors.

The increased prevalence of atopic diseases reported in many Western countries is thought to be caused by changes in living conditions. For a long time attention was focused on indoor environmental factors and early feeding patterns, but during recent years other factors have received more attention. An unselected, Swedish, population-based cohort of 904 children were followed from the age of 3 months to 4 years. Questionnaires were sent to the mothers of the children when they were 3 months, 18 months and 4 years of age. A blood sample was taken from a subgroup of the children when they were 4 years old which was analysed for IgE specific antibodies to food and inhalant allergens. The prevalences of asthma, allergic eye-nose reactions, eczema, and food reactions at 4 years of age and a positive blood test were analysed as outcome factors. Features of housing and early feeding patterns were found to have limited effect on the development of allergies in the children. Presence of older siblings resulted in a decreased tendency to produce IgE antibodies. Early exposure to furry animals seemed to prevent the development of asthma. Children who were frequently infected up to 18 months of age showed an increased prevalence of allergic symptoms at 4 years of age. Children of mothers with a higher prevalence of complaints about indoor factors, or who had increased general symptoms or skin or mucous membrane symptoms ran a greater risk of developing various allergic symptoms. However, these children did not have higher levels of IgE antibodies. The reported allergic symptoms in the children may be due to non-immunological reactions, although it is also possible that the mothers may have over-reported such symptoms.

Effects of Indoor Environmental Factors on Respiratory Health of Children in a Subtropical Climate

The prevalence of eczema varies markedly across the globe. It is unclear whether the geographic variation is due to race and/or ethnic differences, environmental exposures, or genetic factors. We investigated the effects of ethnicity and environmental exposures on eczema in Hispanic white and non-Hispanic white children who participated in the Southern California Children's Health Study. We performed a cross-sectional study with sociodemographic predictors and environmental exposures among Hispanic white and non-Hispanic white children ages 4-8 years enrolled in the Children's Health Study, 2002-2003. Eczema prevalence differed by ethnicity: Hispanic whites showed lower prevalence (13.8%) compared with non-Hispanic whites (20.2%), and adjustment for sociodemographic factors did not account for the ethnic difference (odds ratio [OR] 0.79 [95% confidence interval {CI}, 0.65-0.95]). Parental history of allergic disease had a larger effect in Hispanic whites than in non-Hispanic whites (p for interaction = 0.005). High maternal education level (OR 1.46 [95% CI, 1.14-1.87]), parental history of allergic disease (OR 2.21 [95% CI, 1.78-2.76]), and maternal smoking during pregnancy (OR 1.44 [95% CI, 1.06-1.95]) increased the risk of eczema. Indoor environmental factors (e.g., mold, water damage, humidifier use) increased the risk of eczema in non-Hispanic whites independent of a parental history of allergic disease, but, in Hispanic whites, increased risks were observed, primarily in children without a parental history of allergic disease. Hispanic white children in southern California had a lower prevalence of eczema than non-Hispanic whites, and this ethnic difference was not accounted for by sociodemographic differences. The effects of a parental history of allergic disease and indoor environmental exposures on eczema varied by ethnicity, which indicated that the etiology of eczema may differ in Hispanic whites and in non-Hispanic whites.

The purpose of this study was to determine the efficiency of a commercial air cleaner in removing pollens and fungal spores indoors. The effect of the air ventilation rate in a room on the removal efficiency was also investigated. The air cleaner consisted of a HEPA filtration unit and a fan operated at a flow rate of 404 m3 per h. This system was tested in two adjacent but separate bedrooms on the second floor of a single-family home. The system was used in Room A to clean the air; Room B served as a control. The study was conducted during the summer and fall, and an evaporative cooling unit with ducts to each room delivered outside air. The ventilation rate was controlled by adjusting the flow rates of the evaporator with minor adjustment of the window opening to give similar ventilation rates in both rooms. At the beginning of the test, ventilation rates were measured using an SF6 tracer gas method, and ventilation was adjusted so that both rooms had similar air exchange rates. Then an air cle...

Effects of indoor environmental factors on children's respiratory system and pulmonary function tests were investigated in this study. A total of 617 primary school children aged between 9-12 years were included. A standard questionnaire, which includes questions about respiratory symptoms and illness, indoor environmental determinants, family history of respiratory diseases, and smoking habits of the parents, was sent to homes of all children and information was obtained from parents. Children with a family history of asthma, bronchitis, or other chest troubles suffered morning and day/night coughs, shortness of breath, wheezing and asthma, bronchitis, or pneumonia more frequently. Children whose mothers smoked complained of blocked-runny nose and sinusitis more frequently. Pulmonary function levels were diminished in passive smokers and in children whose houses were heated by a wood-burning stove. As a result, passive smoking, using a wood-burning stove for heating, and family history of respiratory diseases are to be considered risk factors for the respiratory system.

The effects of indoor environmental factors on respiratory illness were studied in 15017-12 year old school children in Kuala Lumpur. Exposure to mosquito coil smoke for at least three nights a week was independently associated with asthma and persistent wheeze. Passive smoking, defined as sharing a bedroom with an adult smoker, was independently associated with a chest illness in the past year. No relationships were found between exposure to kerosene stoves, wood stoves, fumigation mat mosquito repellents or aerosol insecticides and respiratory illness. Host factors predictive of at least one respiratory outcome included family history of chest illness, history of allergy, male sex, hospitalization in the neonatal period and low paternal education. With 95% confidence, avoidance of regular exposure to mosquito coil smoke and passive smoking could reduce the prevalences of persistent wheeze, asthma and chest illness by up to 29%. Measurements of lung function confirmed the validity of questions pertaining to wheezing and asthma in the study questionnaire.

Subjective indoor air quality and thermal comfort among adults in relation to inspected and measured indoor environment factors in single-family houses in Sweden-the BETSI study

Algorithms for environmental control in livestock buildings have to be tuned for optimum response of actuators. For tuning, a simple, but dynamic, climate model for a pig house was formulated and validated to predict the environmental changes in a pig house with natural ventilation under varying conditions. A control algorithm was included in the model and tuning of the algorithm has been performed with the model. The tuned algorithm was implemented in a climate controller and data on the results are presented. It was concluded that the model can be used to simulate room temperature and carbon dioxide concentration in heated pig houses with natural ventilation. The dynamics as well as the actual levels of climate parameters showed agreement between simulation results and actual results. The model can be used to find gain factors and time constants for PID-controllers in algorithms for control of room temperature, air quality, and ventilation rate in natural ventilated pig houses. This would enhance fast and accurate tuning controllers in livestock buildings with natural ventilation as compared to on-site hand tuning.

Studies on the diphasic wave form of the galvanic skin reflex

The peripheral blood flow under basal conditions in normal male subjects in the third decade

The damage of dwelling houses constitutes the primary cause of casualties and asset loss in seismic disasters that occurred in Chinese rural areas. The structure of houses is crucial for assessing the vulnerability of rural houses. However, at present, available data on rural housing structure are incomplete and their spatial scales are inconsistent. This paper estimated the amount and ratio of rural houses in five structures, namely 'wood', 'brick', 'mixed', 'reinforced concrete', and 'other', for 2380 counties across China. With the percent- age sampling census data in 2005, four accuracy levels were specified. Then, a set of down-scaling models were established, where the impact of climate, economic development level and ethnic minority cultural factors on rural housing structure, as well as the spatial autocorrelation of neighboring spatial units were considered. Based on the estimation results, a database of county-level rural housing structure was established, based on which the vul- nerability of rural houses in different areas was clarified.