Home interventions are effective at decreasing indoor nitrogen dioxide concentrations

Nitrogen dioxide (NO₂), a by‐product of combustion produced by indoor gas appliances such as cooking stoves, is associated with respiratory symptoms in those with obstructive airways disease. We conducted a three‐armed randomized trial to evaluate the efficacy of interventions aimed at reducing indoor NO₂ concentrations in homes with unvented gas stoves: (i) replacement of existing gas stove with electric stove; (ii) installation of ventilation hood over existing gas stove; and (iii) placement of air purifiers with high‐efficiency particulate air (HEPA) and carbon filters. Home inspection and NO₂ monitoring were conducted at 1 week pre‐intervention and at 1 week and 3 months post‐intervention. Stove replacement resulted in a 51% and 42% decrease in median NO₂ concentration at 3 months of follow‐up in the kitchen and bedroom, respectively (P = 0.01, P = 0.01); air purifier placement resulted in an immediate decrease in median NO₂ concentration in the kitchen (27%, P < 0.01) and bedroom (22%, P = 0.02), but at 3 months, a significant reduction was seen only in the kitchen (20%, P = 0.05). NO₂ concentrations in the kitchen and bedroom did not significantly change following ventilation hood installation. Replacing unvented gas stoves with electric stoves or placement of air purifiers with HEPA and carbon filters can decrease indoor NO₂ concentrations in urban homes.     

Toluene removal from indoor air using a miniaturized photocatalytic air purifier including a preceding adsorption/desorption unit

The performance of the miniaturized photocatalytic air purifier including a continuous adsorption/desorption unit with a zeolite particles-loaded honeycomb rotor was investigated in the photocatalytic purification of 1 m³ air containing toluene at concentrations of 3-11 mg m⁻³ (about 1-3 ppmv). While operating the continuous adsorption/desorption unit only, and for desorption temperatures controlled within the range of 90-120 and 130-160 °C, the unit took approximately 10 min to reduce the toluene concentration in a 1 m³ room, to a value of almost zero. Almost the same time courses of toluene concentrations were obtained when the photocatalytic reactor was switched on. This result clearly shows that the rapid decrease in the toluene concentration in the 1 m³ room is mainly due to the adsorption of toluene onto the zeolite rotor. When the reactor was switched off, the concentration of toluene desorbed into the 0.022 m³ reactor box increased rapidly and then levelled off in 10 min. On the other hand when the reactor was switched on, the toluene concentration in the reactor box increased rapidly, passing through a maximum in 10-150 min, and then decreasing to a value near zero, leading to the toluene concentration in the 1 m³ room becoming negligible. The apparent rates of decomposition determined from the decreasing toluene concentration in the reactor box were 10-fold smaller than the intrinsic rate constant in the Langmuir-Hinshelwood equation, which would suggest that the desorption process of toluene from the rotor is the rate-limiting. All the decomposition experiments were performed using the same zeolite rotor and photocatalytic reactor over a six month period; and the runs were repeated more than one hundred times. Nevertheless, there was no distinct decrease in decomposition activity of the photocatalyst or any significant loss in ability for the zeolite rotor to adsorb toluene could be seen, indicating that these materials can perform constantly over a long period of time. However, as the rotor will sooner or later become saturated with toluene, it may become necessary to introduce a regeneration procedure in order to periodically remove toluene from the rotor.     

密闭空间SO2气体净化效果的模拟

SO2气体是室内空气污染的一个重要来源。根据碱性溶液吸收SO2气体的机理，研发了一台空气净化量为80～100m3／h的空气净化器，初步测试表明该净化器能很好的吸收室内空气中微量SO2气体。建立了密闭空间的SO2净化模型，利用Fluent模拟了典型案例下的净化效果，并研究了净化器的净化气量和放置位置对净化效果的影响。     

室内空气品质营造技术措施

随着我国经济、工业化、城市化的快速发展,气候和环境问题日益凸显,大气环境和室内空气污染问题逐渐加剧,人们身心健康面临严重威胁,亟须寻找高效实用的解决方法。从室内空气品质的涵义入手,总结了室内空气品质营造方法和标准规范,其中在装饰装修设计过程中对所使用的材料进行预评价,能够有效降低污染物超标风险;而新风系统以其高效、节能的优点,被认为是最具前景的技术措施。     

新型液相介质气体净化器脱硫效率初探和优化实验设计研究

新型液相介质气体净化器是一种复合净化机理的针对中小型燃煤工业锅炉的脱硫除尘一体化装置，通过初步应用表明，其脱硫效率能达70％以上，整个系统运行稳定可靠。但是由于没有建立参数优化标准，制约了其市场化应用前景，所以本文也探讨了优化实验设计。     

净水器过滤纸的研制

采用木质活性炭为主要原料,利用植物纤维提供网状结构,再添加涤纶纤维来改善纸页的过滤性能,制备了可以满足过滤要求的净水器专用活性炭过滤纸。研究成果如下:确定了抄造活性炭过滤纸的各项工艺条件,各组分的比例参数(按绝干量计)活性炭48%;针叶木浆42.6%;涤纶纤维9.4%;CPAM0.08%;AKD0.2%;PAE0.7%。对自制的活性炭过滤纸按最优工艺条件抄造后,检测其技术指标,其抗张指数为14.25N.m/g,湿抗张指数为5.65N.m/g,Cobb值正反面分别为28.9g/m2和15.5g/m2,过滤速度为32.15ml/(m2.s),滤前余氯量≥0.5mg/L,CODCr值≥16mg/L,滤后余氯量≤0.05mg/L,滤后CODCr值≤7.4mg/L,使用寿命为15天。     

The effect of a photocatalytic air purifier on indoor air quality quantified using different measuring methods

The effect on indoor air quality of an air purifier based on photocatalytic oxidation (PCO) was determined by different measuring techniques: sensory assessments of air quality made by human subjects, Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and chromatographic methods (Gas Chromatography/Mass Spectrometry and High-Pressure Liquid Chromatography with UV detection). The experiment was conducted in a simulated office, ventilated with 0.6 h⁻¹, 2.5 h⁻¹ and 6 h⁻¹, in the presence of additional pollution sources (carpet, chipboard and linoleum). At the lowest air change rate, additional measurements were made with no pollution sources present in the office. All conditions were tested with the photocatalytic air purifier turned on and off. The results show that operation of the air purifier in the presence of pollutants emitted by building materials and furniture improves indoor air quality, as documented by sensory assessments made by human subjects. It also reduces concentrations of many chemical compounds present in the air as documented by the PTR-MS technique. For the lowest ventilation, results from measurements using the chromatographic methods have similar tendency, however many of the 50 compounds that were targeted for analysis were not detected at all, independent of whether the purifier was on or off. For the two conditions with higher ventilation the results were inconclusive.     

农村地窖水处理方法

采用慢滤水处理工艺是解决地窖水处理的较好方法，本文研制的净水器适合于缺水地区的农村家庭使用。     

粒状腐植酸净水剂处理含铜废水的研究

以重庆市南桐风化煤为原料制备粒状腐植酸净水剂，用静态实验法找出了处理含铜不的适宜条件，再支用动态实验法处理Ｃｕ＾２＋１２４ｍｇ．Ｌ＾－１的镀铜漂洗水，     

电子气体净化器现状与趋势

电子气体净化器是对电子气体进行在线净化,使主要杂质含量由10-6级降低到10-9、10-12级的关键纯化装置。与电子气体一样,同属我国亟待发展的战略资源与关键技术。从技术和市场角度,对电子气体净化器国内外现状和发展做总体性概括、介绍和展望。