Makiko Nakajima
@it-hiroshima.ac.jp
Department of Architectural Engineering, Faculty of Engineering
Hiroshima Institute of Technology
I received my M.S. (Engineering) and Ph.D. (Engineering) degrees from Kyoto University. I have continuously studied exterior wall staining by aerial algae, a type of bioaerosol, from a thermal-environmental perspective. Aerial algae are a type of algae that can grow in the atmosphere and attach to and grow on exterior wall surfaces, causing staining and material degradation. We are attempting to quantify the growth and development of aerial algae from the physical environment, such as temperature, humidity, and solar radiation. So far, we have conducted a survey of the actual growth of aerial algae in Kyoto City and an environmental survey in an actual building, and have developed a model for predicting algae growth that incorporates a thermal moisture property analysis method. Currently, we are studying methods to prevent the growth of aerial algae, which are Poikilohydric plants, by utilizing their characteristics. In addition, he has experience in conducting temperature, humidity, a
RESEARCH, TEACHING, or OTHER INTERESTS
Architecture, Building and Construction, Civil and Structural Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Jianjian Hou, So Fujiyoshi, Ishara Uhanie Perera, Yukiko Nishiuchi, Makiko Nakajima, Daisuke Ogura, Kyoko Yarimizu, and Fumito Maruyama
Springer Science and Business Media LLC
Makoto Kokubo, Daisuke Ogura, Makiko Nakajima, Fumito Maruyama, So Fujiyoshi, Jun Noda, and Ayako Fujieda
EDP Sciences
Microorganisms in our living environment may affect human health. Microbial suppression by air cleaners and disinfecting agents may provide protection from pathogenic materials. However, excessive microbial suppression can negatively affect human health; thus, an appropriate level of microbiome control is beneficial. It is not well understood how physical environmental conditions, such as temperature and relative humidity, and human lifestyles and behaviors affect indoor microorganisms. To understand the relationship between physical environmental conditions and microbial communities in the human living environment, we measured temperature and relative humidity and collected microbial samples in modern and traditional Japanese houses. In this study, bacteria and fungi were the target microorganisms. In both houses, the DNA concentration of microorganisms on floor surfaces was high when the average relative humidity of the room was high. The same tendency was observed for the beam and pillar surfaces in the traditional house. Although more careful consideration is needed for some indoor surfaces, such as storage ceilings and air conditioner outlets, seasonal changes in relative humidity and DNA concentrations of microorganisms on indoor surfaces exhibit some correlation.
Makoto Kokubo, So Fujiyoshi, Daisuke Ogura, Makiko Nakajima, Ayako Fujieda, Jun Noda, and Fumito Maruyama
MDPI AG
In our living environment, there are various microorganisms that are thought to affect human health. It is expected that excessive microbial suppression can have a negative effect on human health and that the appropriate control of the microbiome is beneficial to health. To understand how the physical environment, such as temperature and relative humidity, or housing itself affects the microbiome in a rural house, we measured temperature and humidity and collected microbial samples in a traditional Japanese house with a thatched roof. The relative humidity of outdoor air was over 60% most of the day throughout the year. Indoor and outdoor air temperature and humidity were closer to each other in summer than in winter. The DNA concentration of indoor surfaces correlated with the relative humidity, especially with the lowest annual relative humidity. In the thatched roof, outside surface relative humidity often reached 100%, and the occurrence of condensation can affect the DNA concentrations. A high percentage of archaea were detected in the house, which is not a common characteristic in houses. In addition, the microbial community was similar outdoors and indoors or in each room. These characteristics reflect the occupants’ behaviour, including opening the windows and partitions in summer. In the future, it will be necessary to conduct continuous surveys in various houses, including traditional and modern houses, in Japan.
Makiko Nakajima, Daisuke Masueda, Shuichi Hokoi, and Takayuki Matsushita
SAGE Publications
The discoloration of building facades due to airborne algae is observed in our surroundings. The growth conditions of these algae are not yet fully understood, and efficient measures for preventing the growth of the algae are not presently available. The objective of this study was to investigate the effects of the ambient environment and building structure on algal growth. A residential building in a cold region of Japan was surveyed. The roof was a multi-layered structure comprising a semi-transparent film, an air layer, and a layer of insulation from the outside, supported by rafters. The soiled state was visually observed by taking photographs. On the northeast (NE) and northwest (NW) roofs, several black stripes appeared 4 months after cleaning. The soiling increased in the spring and autumn. The soiling first appeared on the film backed by the rafter and then extended to the film backed by the air layer. The condensation time during the day in the rafter part was longer than that in the air-layer part. Condensation occurred during the night, but its frequency exhibited no dependence on the orientation of the roof. Algae tend to die when exposed to an environment with a temperature higher than 45°C. The NE roof had the shortest period with a surface temperature of >45°C. These measurements agreed well with the survey results, which indicated that the soiling mainly occurred on the NE and NW sides of the roofs. The time for algal growth was estimated under the assumption that algae can grow at surface temperatures ranging from 0 to 45°C, in agreement with the observed soiling. The observed soiling changes were well explained by the algal population calculated via a growth predictive model according to the algal temperature and relative humidity.
Makiko Nakajima, Daisuke Masueda, Shuichi Hokoi, Chikahiro Miyake, Shinya Wada, and Satoru Takada
Elsevier BV
Makiko Nakajima, Shuichi Hokoi, Daisuke Ogura, and Chiemi Iba
Elsevier BV
M. Nakajima, D. Masueda, S. Hokoi, and T. Matsushita
CIMNE
. Discoloration of building facades due to airborne algae is observed in our surroundings. The growth conditions of these algae are not fully clear yet, and efficient preventive measures have not yet been determined. This study was aimed at investigating the influence of ambient environment and building structure on algal growth. A residential building in the cold region of Japan was surveyed. The roof was a multilayered structure consisting of a semi-transparent film, an air layer, an outside insulation layer, and was supported by rafters. The soiled state was visually observed and recorded through pictures, and seemed to be particularly increased in autumn. Several black stripes appeared on the northeast (NE) roof four months after its cleaning. The soiling first appeared on the film backed by the rafter, and then extended to the film backed by the air layer. It rarely appeared on the southeast roof. The roof-surface temperature was measured and a stripe-shaped distribution was observed. The temperature of the film with rafter was higher and lesser than that of the film with the air layer during the night and in the early morning, respectively. Although condensation occurred nightly, its frequency showed no orientational difference. Algae can die when exposed to a temperature higher than 40 °C. The southwest roof had the longest period of a surface temperature over 40 °C, while the northwest (NW) roof had the shortest period of this surface temperature. These measurements corresponded well to the survey results according to which soiling mainly occurred on the NE and NW sides of roofs. The time for algal growth was estimated assuming that algae can grow at surface temperatures between 0 and 40 °C.
Makiko Nakajima, Shuichi Hokoi, Daisuke Ogura, and Chiemi Iba
Elsevier BV
Makiko NAKAJIMA, Shuichi HOKOI, Daisuke OGURA, and Chiemi IBA
Architectural Institute of Japan
This research aims to quantify the relationship between airborne algal growth/death on the exterior walls of the building and environmental factors such as surface temperature and humidity. Based on this, the study proposes a prediction model for the algal growth, where the algal growth was evaluated as algal cell number. The proposed model was used to simulate the change in algal cell number (growth and/or death), taking into consideration the temperature, humidity, and incident solar radiation. Results indicate that the algal growth rate agreed well with the measured L* value (brightness).
Makiko NAKAJIMA, Shuichi HOKOI, and Daisuke OGURA
Architectural Institute of Japan
Building facades are often discolored by the airborne algae. The algal growth is strongly influenced by the water supply. In this study, the environmental conditions and the discoloration of walls were measured on the existing building walls on which the algae grew, and the relationship between them was examined. The ambient air humidity was high at the surveyed building mainly because of the topography and trees. Visual evaluations and the L* values of the wall sections that received the direct solar radiation were not discolored because the algae could not grow on wall sections that became high temperatures.
Makiko NAKAJIMA, Shuichi HOKOI, and Daisuke OGURA
Architectural Institute of Japan
Building facades often become black and/or green because of the airborne algae. The algal growth is mainly affected by the water supply, as well as other environmental factors also influence. In this study, we aimed to elucidate the relationship between the algal growth and environmental conditions. We carried out a field survey on the algal growth in Kyoto City. To investigate the factors that algal growth on the wall under the eaves, we calculated wall surface temperature and humidity considering the coupled heat and moisture transfer, and showed a possible relationship between algal death and high temperature and low humidity.