Indoor air quality and thermal comfort in temporary houses occupied after the Great East Japan Earthquake

Thermal conditions and indoor concentrations of aldehydes, volatile organic compounds (VOCs), and NO₂ were investigated in 19 occupied temporary houses in 15 temporary housing estates constructed in Minamisoma City, Fukushima, Japan. The data were collected in winter, spring, and summer in January to July 2012. Thermal conditions in temporary log houses in the summer were more comfortable than those in pre‐fabricated houses. In the winter, the indoor temperature was uncomfortably low in all of the houses, particularly the temporary log houses. Indoor air concentrations for most aldehydes and VOCs were much lower than the indoor guidelines, except for those of p‐dichlorobenzene, acetaldehyde, and total VOCs. The indoor p‐dichlorobenzene concentrations exceeded the guideline (240 μg/m³) in 18% of the temporary houses, and the 10^?3 cancer risk level (91 μg/m³) was exceeded in winter in 21% due to use of moth repellents by the occupants. Indoor acetaldehyde concentrations exceeded the guideline (48 μg/m³) in about half of the temporary houses, likely originating from the wooden building materials. Indoor NO₂ concentrations in the temporary houses were significantly higher in houses where combustion heating appliances were used (0.17 ± 0.11 ppm) than in those where they were not used (0.0094 ± 0.0065 ppm).     

Damage to sewage systems caused by the Great East Japan Earthquake,and governmental policy

The Great East Japan Earthquake and its accompanying liquefaction and tsunami severely damaged many sewage systems including sewage pipes, manholes, pumping stations and sewage treatment plants over a wide area from Tohoku to the Kanto region. We conducted a questionnaire survey, interview survey and on-site confirmation in order to summarize and categorize the damage factors that shut down facilities such as drainage systems and treatment systems. We also studied the effectiveness of countermeasures to prevent liquefaction of the sewage system. The results showed that 90% of sewage pipes and 70% of manholes were damaged by liquefaction and that 54% of wastewater treatment plants and 75% of pumping stations were damaged by tsunami. Nevertheless, no severe damage was found along sewage pipe sections where liquefaction countermeasures had been executed, suggesting that the countermeasures are effective.     

Characteristics of Tsunami Damage to the Tide Walls in Iwate Prefecture from the Great East Japan Earthquake

This research paper describes the tsunami damage to tide walls observed using aerial photographs and field investigations at 13 locations along the coast of Iwate Prefecture, where significant tsunami damage occurred as a result of the Great East Japan Earthquake. This paper also summarizes the characteristics of the damage. The tide walls in Iwate Prefecture were constructed on a ria （hilly type） coast, this geographical feature of lwate being different from that of the other disaster areas, primarily Miyagi and Fukushima Prefectures. The results of our investigations show that all the devastated tide walls suffered from overflow before being damaged. In particular, the sloping and vertical type tide walls with slope protection were damaged by scouring of the infill sand or back fill soil due to the overflow of the tsunami. In the case of vertical type tide walls without slope protection, damage was caused by scouring of the back fill soil.     

Investigation of the heat generation and spontaneous ignition of disaster waste generated after the 2011 Great East Japan Earthquake

The Great East Japan Earthquake that occurred on 11 March 2011 was the largest earthquake in recent Japanese history, and resulted in the generation of large amounts of disaster waste. As a result, many ‘outdoor storage areas’ were established within disaster areas. These piles include various combustible materials such as wood, paper, and plastics, as well as non-combustible materials from destroyed buildings. More than 30 fires occurred in succession at waste storage areas in the Tohoku region, from May to September 2011.One of the causes of these fires is believed to be the proliferation of microorganisms and fermentation of organic material present in the waste piles; the heat generated during fermentation may ultimately result in spontaneous ignition. In this study, we collected samples from outdoor storage areas at which fires have occurred. We then conducted thermal analyses to obtain basic data, and finally developed safety measures to prevent the recurrence of fire. Based on the results, it was reveal that when the amount of heat generated exceeds the amount of heat discharged, the possibility increases for the heat of fermentation that arises from the rotten tatami mats and wood chips and the like to trigger of spontaneous ignition.     

技术过度自信对工程项目建设的影响及对策研究 ——东日本大地震及其次生灾害的思考

以东日本大地震及其次生灾害为例,从人为因素分析入手,揭示出技术过度自信是东日本大地震及其次生灾害的一个重要的人为因素。文章围绕技术过度自信的概念、类型、成因及作用机理进行了探讨。分析了技术过度自信对工程项目建设存在的影响,即决策风险、勘察风险、设计风险、施工风险和监理风险。并从控制机制和制度、交流与学习、培训和宣传、理论研究等四个方面提出了预防或减少技术过度自信的对策及建议。     

Residential air exchange rates in three major US metropolitan areas: results from the Relationship Among Indoor, Outdoor, and Personal Air Study 1999–2001

Abstract We report approximately 500 indoor–outdoor air exchange rate (AER) calculations based on measurements conducted in residences in three US metropolitan areas in 1999–2001: Elizabeth, New Jersey; Houston, Texas; and Los Angeles County, California. Overall, a median AER across these urban areas and seasons was 0.71 air changes per hour (ACH, or per hour; n = 509) while median AERs measured in California (n = 182), New Jersey (n = 163), and Texas (n = 164) were 0.87, 0.88, and 0.47 ACH, respectively. In Texas, the measured AERs were lower in the summer cooling season (median = 0.37 ACH) than in the winter heating season (median = 0.63 ACH), likely because of the reported use of room air conditioners as Houston is typically hot and humid during the summer. The measured AERs in California were higher in summer (median = 1.13 ACH) than in winter (median = 0.61 ACH). Because the summer cooling season in Los Angeles County is less humid than in New Jersey or Texas, natural ventilation through open windows and screened doors likely increased measured AER in California study homes. In New Jersey, AER were similar across heating and cooling seasons, although the median AER was relatively lower during the spring.

Practical Implications

Adequate ventilation or air exchange rate (AER) for an indoor environment is important for human health and comfort, and relevant to building design and energy conservation and efficiency considerations. However, residential AER data, especially measured by more accurate non‐toxic tracer gas methodologies, are at present quite limited worldwide, and are insufficient to represent the variations across regions and seasons within and between homes, including apartments and condominiums in more densely populated urban areas. The present paper presents quantitative and qualitative data to characterize residential AERs in three US urban areas with different climate attributes.