Recent studies have reported linear physiological changes in circulatory, cardiovascular, and autonomic systems at carbon dioxide (CO₂) exposures ranging between 500 and 5,000 ppm; these effects are evident. Recent experimental studies suggested that CO₂ might affect psychomotor performance including decision making or problem resolution, beginning at 1,000 ppm during short-time exposure. Many epidemiological studies have demonstrated a relationship between low-level exposure to CO₂ and sick building syndrome (SBS) symptoms; however, other mixed indoor pollutants are also likely to involve the SBS symptoms. Maintaining a CO₂ concentration below 1,000 ppm in the indoor environment of a building would represent an effective means of preventing effects upon human health and psychomotor performance. In addition, for efficient energy control of CO₂ intruding a building from ambient air, urgent suppressing the rise of atmospheric CO₂ concentration is required.

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Nitrogen dioxide (NO₂) is one of air pollutants, and environmental standards are set for the outdoor conditions. In the outdoor environment, NO₂ is mainly emitted from vehicles and factories, and in the indoor condition, the high concentrations of NO₂ are generated from open-type oil stoves especially in winter. NO₂ clearly has an adverse effect on human lungs; therefore it is important to reduce the indoor NO₂ concentration in order to decrease the incidence of asthma, which can be said as a national disease. There are some reports related to indoor NO₂ concentration measurements in several Japanese areas, which mainly used diffusive sampling device as a measurement method. Although the diffusive sampling device is easy for use without special technique, it needs 24-hours for sample collection and the analytical results could not obtained on site because ion-chromatograph instrument is needed for analysis. In this report, the analytical chip which employed the reaction between salzman's reagent and NO₂ in the porous glass is described, and indoor NO₂ measurement using the analytical chip is also mentioned.

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Ammonia is often generated in our living environment by various mechanisms, and the emission source includes plants and animals. Because ammonia is one of the chemicals which shows the strong odor, the long-term exposure to high concentration of ammonia might be rare case. However, ammonia should still be attracted as an important inorganic chemical compound due to the facts that there were indoor environments whose concentration of ammonia was around the odor threshold value (1.5 ppm), according to actual measurement results. This article describes the generation mechanisms and behavior of ammonia, and measurement methods were interpreted with active and passive samplers including sampler for onsite use Moreover, novel studies which aim to use the measured ammonia data as information from plants and human beings were introduced.

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Foul odors in the hospital environment mainly come from patients, specifically their excrement and discharges. In the clinical laboratory, there are many origins of bad odors, including patient specimens and chemicals. We investigated and discussed odors detected in the clinical laboratory of our hospital. The laboratory handles many kinds of specimens, such as samples of blood, urine and feces obtained from patients. These specimens generate volatile chemicals throughout the examination process, starting from processing the samples all the way down to their storage. The microbiology laboratory is particularly odious, with smells coming from culture media as well as specimens with pathogens, such as sputum, urine, blood, feces, cerebrospinal fluid and pus. Although some methods to counter these odors, such as deodorization and ventilation, have been implemented, they are not very effective. Methods based on cost performance must be developed. Medical facilities must remain hygienic and comfortable, so developing effective methods of eliminating odors remains an issue to be resolved.

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