Indoor air quality assessment of daycare facilities with carbon dioxide,temperature, and humidity as indicators

Poor indoor air quality (IAQ) in daycare facilities affects both attending children and care providers. Incident rates of upper-respiratory-tract infections have been reported to be higher in children who attend daycare. Excessive carbon dioxide (CO2) exposure can cause several health effects and even sudden infant death. For this study, 26 facilities were randomly selected in a Midwestern county of the United States. CO2, room temperature, and relative humidity were used as indicators for IAQ and comfort levels. These IAQ parameters were continuously monitored for eight hours at each facility by a direct-reading instrument that was calibrated before each measurement. More than 50 percent of the facilities had an average CO2 level over the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standard of 1,000 parts per million (ppm). For temperature and relative humidity, respectively, 42.3 percent and 15.4 percent of facilities were outside of the ASHRAE-recommended comfort zones. The nap-time average CO2 level was about 117 ppm higher than the non-nap-time level. The increment of the nap-time CO2 level in the sleeping-only room over the level in multipurpose rooms was statistically significant (p < .05). According to stepwise multiple regression analysis, nap-time CO2 level was predicted by CO2 level before occupancy, nap-time average temperature, carbon monoxide, and child density (R2 = .83). It is recommended that an appropriate IAQ standard for daycare facilities be established and that children should not be placed in a completely isolated room during nap time.     

Effect of temperature and relative humidity on variola virus in crusts.

The viability of variola virus in crusts under different conditions of temperature and relative humidity was studied for 16 weeks. At the ambient temperature of 25.8-26.4°C and 85-90% relative humidity, the virus survived only 8 weeks but at lower temperatures and relative humidities the survival time was considerably prolonged.     

An international survey of indoor air quality,ventilation, and smoking activity in restaurants: a pilot study

During a pilot study of indoor air quality in restaurants, a survey was performed in 34 medium-priced restaurants in six countries in Asia, Europe, and North America using a uniform protocol. The concentration of selected constituents of environmental tobacco smoke (ETS) present in occupied areas was determined during lunch and dinner periods by measuring the levels of four particulate-phase markers and two gas-phase markers. The particulate-phase markers determined were respirable suspended particles, ultraviolet particulate matter, fluorescing particulate matter, and solanesol particulate matter. The gas-phase markers were nicotine and 3-ethenylpyridine (3-EP). Correlation between the markers was investigated to explore an improved monitoring approach. It was concluded that at least one marker in each phase was necessary to describe adequately the ETS load. An assessment was made of the ventilation system in each restaurant, and effective ventilation rates were determined based on CO(2) measurements. Smoking activity was also monitored. These data were used to model nicotine and 3-EP concentrations that resulted in a satisfactory prediction of their levels, especially at the higher concentrations. A total number of 1370 questionnaires were returned by the restaurant patrons in five countries. In some countries, dissatisfaction rates above 20% were observed for draft, freshness of air, and noise. The dissatisfaction rates related to tobacco smoke were less than 20%, which is lower than would be predicted based on measured ETS levels. Based on the results of this international pilot study, recommendations are given for future studies of this type.     

The toxic effect of deltamethrin on linyphiid and erigonid spiders in connection with ambient temperature,humidity, and predation

The first part of this study concerns the effect of temperature and air humidity on the toxicity of deltamethrin to the erigonidOedothorax apicatus. The second part concerns the effect of deltamethrin on behavior of linyphiids and erigonids with respect to their ability to escape from predators and to select between unfavorable (dry) and favorable (moist) habitat conditions. The toxic effect of deltamethrin was highest at the combination of high temperature and low air humidity. It was concluded that the spider's sensitivity to drought is increased by this pyrethroid. Affected spiders, however, are less able to select moist habitat conditions than unaffected ones. Walking speed of spiders was decreased by exposure to deltamethrin and their predation by carabid beetles was increased. It was concluded that the effect observed under field conditions is the result of a combination of neurological, physiological, and behavioral disturbance.     

温度和湿度对硫酰氟熏蒸灭鼠效果的影响

目的观察温度和相对湿度对硫酰氟熏蒸灭鼠效果的影响。方法试验在模拟熏蒸箱内进行,均匀设计实验方案,通过单因素和多因素分析判断温度、湿度和剂量对硫酰氟熏蒸灭鼠效果的影响。结果单因素分析显示硫酰氟剂量和温度影响灭鼠效果,剂量从0．750g／m＾3增至0．892g／m＾3,鼠死亡率从30％升至70％;不同湿度（25％485％）鼠死亡率差异无统计学意义;均匀设计多因素分析显示相对湿度、剂量与小鼠的死亡率有关,以小鼠的死亡率为应变量,温度、相对湿度和剂量为自变量,进行二次型回归分析,得回归方程：P=-0．00839H＋1．03677D。结论硫酰氟熏蒸灭鼠效果好,在实际工作中,应根据湿度和温度变化科学调整熏蒸时的投药剂量。     

调温调湿日照实验系统

介绍了调温调湿日照实验系统的构造原理及软硬件设计。其控制电路采用8031单片机,用单片机完成数据处理、温度和湿度的调节与控制以及显示和打印。它是一台新型室外专用实验装置。     

Relation of peak expiratory flow rates and symptoms to ambient ozone.

The temporal association between peak expiratory flow rates (PEFRs) and ambient ozone (O3) was studied in a group of 287 children and 523 nonsmoking adults in Tucson. In children, noon PEFRs were decreased on days when there was a higher O3 concentration; children with physician-confirmed asthma experienced the greatest decrease in noon PEFR. Evening PEFR levels were also significantly related to O3 in children, especially asthmatics. Among adults, evening PEFRs were decreased in asthmatics who spent more time outdoors on days when O3 levels were higher. After we adjusted for covariates, significant effects of interactions of 8-h O3 levels with particulate matter (PM10) and temperature on daily PEFR were found. There was some overnight effect of 8-h O3 on morning PEFRs. In general, the respiratory response to low-level ambient O3 is acute, occurs more in asthmatics, and increases as temperature and PM10 increase.     

温湿度对硫酰氟熏蒸灭蝇效果的影响研究

目的研究不同温度、湿度对硫酰氟熏蒸处理家蝇效果的影响。方法在密封模拟熏蒸箱内,根据均匀设计实验分组确定的实验条件,对家蝇熏蒸24 h,观察其死亡率。结果 硫酰氟剂量、湿度单因素以及剂量、温度交互作用均对杀灭效果有影响;家蝇的死亡率随着温度的平方、剂量的升高而升高,高湿度增加家蝇死亡率。结论根据实验结果建立不同温度、湿度条件下硫酰氟现场熏蒸用量的回归方程,并进行现场验证,修正参数,对熏蒸现场操作人员科学用药有指导作用。     

Respirator cartridge efficiency studies: VII. Effect of relative humidity and temperature.

Cartridge service life is not appreciably affected at relative humidities below 50%. However, performance is severely compromised when the humidity exceeds 65%. Experimental values are compared from those calculated from the adsorption isotherm, Mecklenburg and modified Wheeler equations. Calculations indicate that temperature does not play a significant role in service life predictions.     

天平室温度和湿度的变化对测尘滤膜称量结果的影响

目的 研究称量环境温度和湿度的变化对采样前后滤膜称量结果的影响.方法 在(18±1)℃和(28±1)℃2个温度下,调节天平室的湿度,于不同气象条件下对采集煤尘前后的测尘滤膜进行称量,计算采样后承载滤膜的增量(相同称量气象条件下的承载滤膜质量减去相对应的空白滤膜的质量),对结果进行比较分析.结果 空白滤膜和承载滤膜在(18±1)℃和(28±1)℃的称量结果波动范围分别为0.10～0.13 mg和0.06～0.09 mg,温度和湿度均变化时,称量结果波动范围为0.12～0.16 mg;各组承载滤膜增量均值在(18±1)℃和(28±1)℃的波动范围分别为0.07～0.10 mg和0.04～0.08 mg,温度和湿度均变化时,波动范围为0.09～0.14 mg.同一温度组内,空白滤膜组和承载滤膜组的称量均值随着湿度升高呈上升趋势,而各承载滤膜的增量与湿度不相关;在相同湿度下,(18±1)℃时承载滤膜增量高于(28±1)℃,差异有统计学意义(P＜0.01);除总尘高增量组外,其余各组称量均值在(18±1)℃随湿度升高的上升趋势比(28±1)℃更明显,差异有统计学意义(P＜0.01).当湿度相同时,各承载滤膜组(18±1)℃的增量均值高于(28±1)℃,差异有统计学意义(P＜0.01).结论 实验室温度和湿度的变化导致测尘滤膜称量结果的波动,湿度对采样前后滤膜增量影响不明显,但低温时滤膜增量高于高温时,会影响粉尘浓度测定结果.     

密闭环境中温度和湿度对地砖氡析出率影响

目的探讨密闭环境中温度和相对湿度对地砖氡析出率的影响规律.方法以市售普通釉面地砖为研究对象,在0.25 m^3模拟舱内,用Model 10027型连续测氡仪检测不同温度和相对湿度下的氡浓度,计算氡析出率.结果在测定范围内,氡析出率与温度符合三次函数关系ER=-0.0293T3＋2.5543T2-72.82T＋687.27（R2=0.9669）;氡析出率与相对湿度符合三次函数关系ER=0.0001RH3-0.0354RH2＋2.3391RH-25.044（R2=0.9889）.结论温度、相对湿度是影响地砖氡析出率的重要环境因素.     

Evaluation of a portable gas chromatograph with photoionization detector under variations of VOC concentration,temperature, and relative humidity

The objective of this present study was to evaluate the performance of a portable gas chromatograph-photoionization detector (GC-PID), under various test conditions to determine if it could be used in occupational settings. A mixture of 7 volatile organic compounds (VOCs)—acetone, ethylbenzene, methyl isobutyl ketone, toluene, m-xylene, p-xylene, and o-xylene—was selected because its components are commonly present in paint manufacturing industries. A full-factorial combination of 4 concentration levels (exposure scenarios) of VOC mixtures, 3 different temperatures (25°C, 30°C, and 35°C), and 3 relative humidities (RHs; 25%, 50%, and 75%) was conducted in a full-size controlled environmental chamber. Three repetitions were conducted for each test condition allowing for estimation of accuracy. Time-weighted average exposure data were collected using solid sorbent tubes (Anasorb 747, SKC Inc.) as the reference sampling medium. Calibration curves of Frog-4000 using the dry gases showed R² > 0.99 for all analytes except for toluene (R² = 0.97). Frog-4000 estimates within a test condition showed good consistency for the performance of repeated measurement. However, there was ～41–64% reduction in the analysis of polar acetone with 75% RH relative to collection at 25% RH. Although Frog-4000 results correlated well with solid sorbent tubes (r = 0.808–0.993, except for toluene) most of the combinations regardless of analyte did not meet the <25% accuracy criterion recommended by NIOSH. The effect of chromatographic co-elution can be seen with m, p-xylene when the results are compared to the sorbent tube sampling technique with GC-flame ionization detector. The results indicated an effect of humidity on the quantification of the polar compounds that might be attributed to the pre-concentrator placed in the selected GC-PID. Further investigation may resolve the humidity effect on sorbent trap with micro GC pre-concentrator when water vapor is present. Although this instrument does not fulfill the accuracy criterion specified in the NIOSH technical report No. 2012–162, it can be used as a screening tool for range finding monitoring with dry gases calibration in the occupational setting rather than compliance monitoring.     

Indoor air quality in two urban elementary schools--measurements of airborne fungi, carpet allergens, CO2, temperature, and relative humidity

This article presents measurements of biological contaminants in two elementary schools that serve inner city minority populations. One of the schools is an older building; the other is newer and was designed to minimize indoor air quality problems. Measurements were obtained for airborne fungi, carpet loadings of dust mite allergens, cockroach allergens, cat allergens, and carpet fungi. Carbon dioxide concentrations, temperature, and relative humidity were also measured. Each of these measurements was made in five classrooms in each school over three seasons--fall, winter, and spring. We compared the indoor environments at the two schools and examined the variability in measured parameters between and within schools and across seasons. A fixed-effects, nested analysis was performed to determine the effect of school, season, and room-within-school, as well as CO2, temperature and relative humidity. The levels of all measured parameters were comparable for the two schools. Carpet culturable fungal concentrations and cat allergen levels in the newer school started and remained higher than in the older school over the study period. Cockroach allergen levels in some areas were very high in the newer school and declined over the study period to levels lower than the older school. Dust mite allergen and culturable fungal concentrations in both schools were relatively low compared with benchmark values. The daily averages for temperature and relative humidity frequently did not meet ASHRAE guidelines in either school, which suggests that proper HVAC and general building operation and maintenance procedures are at least as important as proper design and construction for adequate indoor air quality. The results show that for fungi and cat allergens, the school environment can be an important exposure source for children.     

昼夜温差和相对湿度与汕头市居民急性心肌梗死之间的关联性分析

目的 分析汕头市气象条件对急性心肌梗死（AMI）患者死亡的影响和人群易感性,为当地医疗卫生系统提供防治AMI的科学依据。方法 收集2015年1月1日至2020年12月31日汕头市居民死因监测数据库中因AMI死亡的人群数据,利用分布滞后非线性模型分析昼夜温差和相对湿度对AMI死亡的影响及滞后效应。结果 研究期间汕头市因AMI死亡13 932人,男女性别比为1.3∶1,高昼夜温差暴露和低相对湿度暴露与AMI死亡之间存在显著关联,单日滞后效应均在滞后2 d时出现并达到最大（RR=1.019,95%CI：1.000~1.039;RR=1.018,95%CI：1.003~1.034）;累计滞后效应均在滞后0~14 d时达到最大（RR=1.199,95%CI：1.025~1.401;RR=1.279,95%CI：1.117~1.465）。≥75岁老年人和女性是高昼夜温差暴露和低相对湿度暴露条件下的易感人群。结论 昼夜温差和相对湿度与汕头市AMI死亡之间存在显著关联,其影响有明显的滞后性。女性和≥75岁老年人均为高昼夜温差和低相对湿度暴露条件下的易感人群。     

Associations between personal exposures and fixed-site ambient measurements of fine particulate matter, nitrogen dioxide, and carbon monoxide in Toronto, Canada

A longitudinal study investigating personal exposures to PM(2.5), nitrogen dioxide (NO(2)), and carbon monoxide (CO) for cardiac compromised individuals was conducted in Toronto, Canada. The aim of the study was (1) to examine the distribution of exposures to PM(2.5), NO(2), and CO; and (2) to investigate the relationship between personal exposures and fixed-site ambient measurements of PM(2.5), NO(2), and CO. In total, 28 subjects with coronary artery disease wore the Rupprecht & Patashnick ChemPass Personal Sampling System one day a week for a maximum of 10 weeks. The mean (SD) personal exposures were 22 microg m(-3) (42), 14 p.p.b. (6), and 1.4 p.p.m (0.5) for PM(2.5), NO(2), and CO, respectively. PM(2.5) and CO personal exposures were greater than central fixed-site ambient measurements, while the reverse pattern was observed for NO(2). Ambient PM(2.5) and NO(2) were correlated with personal exposures to PM(2.5) and NO(2) with median Spearman's correlation coefficients of 0.69 and 0.57, respectively. The correlations between personal exposures and ambient measurements made closest to the subjects' homes or the average of all stations within the study were not stronger than the correlation between personal exposures and central fixed-site measurements. Personal exposures to PM(2.5) were correlated with personal exposures to NO(2) (median Spearman's correlation coefficient of 0.43). This study suggests that central fixed-site measurements of PM(2.5) and NO(2) may be treated as surrogates for personal exposures to PM(2.5) and NO(2) in epidemiological studies, and that NO(2) is a potential confounder of PM(2.5).     

Damp housing and childhood asthma; respiratory effects of indoor air temperature and relative humidity.

In a questionnaire survey of a random sample of 1000 children aged 7 years, a significantly greater proportion of those living in homes reported as damp were affected by wheeze (22% v 11%), day cough, night cough, and chesty colds. Simultaneous estimation of relative humidity in the bedrooms of 778 children and continuous 7 day recordings of ambient temperature and humidity in a stratified sample of 317 bedrooms showed no association with the same respiratory symptoms. No correlation was found between bedroom conditions and baseline ventilatory function or exercise induced reduction in FEV1. These results run counter to the widely held belief that indoor temperature and humidity are important determinants of respiratory ill health, although they do not directly exclude effects due to mites or moulds, whose survival is determined by the humidity of their respective microenvironments.     

Production of volatile metabolites from streptomyces albidoflavus cultivated on gypsum board and tryptone glucose extract agar-influence of temperature,oxygen and carbon dioxide levels

Streptomyces albidoflavus was cultivated on tryptone glucose extract agar (TGEA) and gypsum board in culture flasks. The medium, the cultivation temperature, and the oxygen and carbon dioxide levels in the supplied air were varied multivariately. Air samples from the cultures were adsorbed on Tenax TA, analysed with the use of thermal desorption-cold trap injection gas chromatography, and identified by mass spectrometry. Alcohols, ketones, terpenes and terpene derivatives, for example geosmin, were produced on both media. On TGEA, sulphur compounds were the dominating products, dimethyl disulphide being produced in major amounts. The medium and the temperature exerted the highest influence on production, but the oxygen and carbon dioxide levels also affected the amounts of some metabolites produced.