In 2004, musty odor causing compounds, geosmin and 2-methylisoborneol, were newly added into the water quality standards for drinking water, and has enhanced the countermeasures by water supply utilities. While, the population affected by the taste and odor issues was within the range of 100～450 million during FY2001～2013, and now under the tendency of increasing. Komárek et al. presented a new classification system of Cyanophyceae. The musty odor producing Cyanophyceae should be also organized based on the new classification with consistency of the conventional generic and species name. Molecular formulae of fishy smell causing compounds were estimated by utilizing the recently innovated mass spectrometry combined with multivariate analyses.

Musty odor of tap water originates from odorous compounds produced by organisms such as algae in water bodies serving as drinking water sources. Simple and rapid detection of odorous compounds in water sources allows an early decision-make to take effective measures including temporary stop of water intake, change of location or depth for water intake, and advanced treatment at water treatment plants. Recent progress in genetic engineering allows to introduce insect olfactory receptors into cultured cells to produce sensitive and selective biosensors. We have been challenging to apply a geosmin-specific sensor cell to monitor geosmin in water.

Odor generated in living spaces is discharged outdoors by ventilation. However due to furniture layouts, the ventilation air flow sometimes does not reach odorous materials, and the resulting lingering of odors causes marked discomfort. A measure against odors in places where malodorous materials remain is the placement of deodorants. A previous study^1） showed the effectiveness of deodorants under ventilation in experiments using small chambers (2m³). In this study, we continuously generated hydrogen sulfide, which contributes to garbage odor, in an experimental space (15.6m³) simulating a real space, and assessed a method for evaluating deodorant performance under ventilation based on the distributions of the hydrogen sulfide concentration in the space before and after the placement of a deodorant. As a result, when the ventilation air flow was obstructed by furniture, a concentration gradient of hydrogen sulfide was present, emanating from its source. When a deodorant was placed in an area with a high hydrogen sulfide concentration, about a 50% reduction in its concentration was confirmed near the deodorant. If a distance between the deodorant and a source of hydrogen sulfide increases, the effect of reducing its concentration was lost. We have concluded that the method proposed in this study can be useful for evaluating deodorants under ventilation.

In the previous paper, we simulated the airflow properties and the odor concentration from an odor bag based on computed fluid dynamics in the case of the self-suction method, which was the official suction method in the triangle odor bag method. In this paper, the suction airflow property and the odor concentration were predicted in the case of the discharge-suction method in which the air in the mask was displaced to the odor in the bag using gap and space as parameters. As a result, it was revealed that even if there was a gap between the mask and the face, they could suction around 80 percent of odor concentration in the bag, and even if there was a large distance between the mask and the face, about 60 percent of odor concentration in the bag could be suctioned.

Indoor malodor of elderly nursing homes often causes complaints from their users. However, eliminating malodor is very difficult due to the variety of causes. In this study, we investigated a nursing home that often received “urine-like malodor” complaints. To clarify the causes and find a solution to the malodor, we investigated both the emitting sources of phenol derivatives as the key urine malodor component and the inhabiting areas of the bacteria that produce β-glucuronidase as the cause of urine malodor. As a result, it was found that p-cresol, among phenol components, has a high correlation with odor intensity. Urine-malodor-causing bacteria were found in several areas, all of which had urine odor such as the surface of the bowl of the portable toilet, a section of carpet beside the bed, and a section of the bed sheet. Continuous use of cleansing and disinfectant products over a year focusing on the areas where the malodor is emitted and malodor-causing bacteria inhabit reduced both the number of the bacteria and the indoor malodor intensity. Thus, focusing on specific areas related malodor can reduce the indoor malodor of elderly nursing homes.

As part of precautionary measures to reduce the increasing incidences of fire in restaurant kitchens, the Tokyo Fire Department has amended part of the Standards for Operation of an Exhaust Duct Associated with Kitchen Equipment (hereinafter referred to as “Standards for Kitchen Equipment”). In the standards for an exhaust duct, the use of materials such as activated charcoal is banned inside a duct, except for materials made with designated non-combustible materials to prevent fire from spreading. Under such conditions, the Japan Association on Odor Environment has established a Committee on Deodorization of Restaurants’ Kitchen Equipment and examined the use of activated carbon without spreading fire. As a result, it was concluded that a material that cannot be admitted as a designated non-combustible material because of a void of a tank packed with activated carbon can be used only after taking effective measures and receiving confirmation from the Tokyo Fire Department. The effective measures are as follows : ① to install deodorizing equipment, containing activated carbon, outside a building, where it can be easily reached for maintenance without being surrounded by combustibles ; ② to use an anti-corrosive copper plate (with a thickness of 1.5mm or more) as an external plate of the deodorizing equipment ; ③ to install a fire damper linked to an exhaust fan between the deodorizing equipment and an exhaust duct (the damper will be opened only when the fan is turned on) ; and ④ to turn off the exhaust fan when a device for preventing flame propagation (i.e., a fire damper or automated fire extinguishing device) is activated.