Indoor Situations Research Articles

The response of Anopheles gambiae s.l. and A. funestus (Diptera: Culicidae) to tents baited with human odour or carbon dioxide in Tanzania

AbstractField studies on the response of Anopheles gambiae s.l. Giles and Anopheles funestus Giles to tents baited with human odour or carbon dioxide were conducted in south-east Tanzania. Two exit traps and a CDC miniature light trap set beside a bed net were used to sample mosquitoes that entered the tent. Human odour, pumped from an underground pit into a bed net attracted a similar number of mosquitoes as a bed net occupied by a human male. Significantly fewer mosquitoes were caught in a tent into which carbon dioxide (300 ml min-1) was pumped than in a human-odour baited tent (9 and 27% for A. gambiae s.l. and A. funestus respectively). A five-fold increase of the carbon dioxide concentration (to 1500 ml min-1) did not increase the catches of A. gambiae s.l. whereas those of A. funestus were increased to 69% of the catches by human odour. Species identifications of A. gambiae s.l. catches showed that A. arabiensis Patton prevailed and that the proportions of A. arabiensis/A. gambiae s.s. did not differ between treatments. It is concluded that in the indoor situation described, human odour other than carbon dioxide is the principal cue to which these malaria vectors are attracted and that the physical presence of a host and carbon dioxide, when used as a kairomone on its own, accounts for only a minor part of the overall attractiveness of man, particularly for A. gambiae s.l.

Indoor Air Chemistry: Formation of Organic Acids and Aldehydes

Laying emphasis on the formation of aldehydes and organic acids, the study has examined the gas-phase reactions of ozone with unsaturated VOCs. The formation of formaldehyde and formic acid was observed for all the three selected unsaturated VOCs: styrene, limonene, and 4-vinylcyclohexene. In addition, benzaldehyde was detected in the styrene-ozone-air reaction system, and acetic acid was also found in limonene-ozone-air system. The study has also examined the gas-phase reactions among formaldehyde, ozone, and nitrogen dioxide and found the formation of formic acid. The nitrate radical was suggested to play an important role in converting formaldehyde into formic acid. Experiments for all the reactions were conducted by using a 4.3 m{sup 3} Teflon chamber. Since the conditions for the reactions were similar to those for indoor environments, the results from the study can be implicated to real indoor situations and can be employed to support the findings and suggestions from the previous studies: certain aldehydes and organic acids could be generated by indoor chemistry.

Passive smoking aboard passenger aircraft

A review of the relevant literature on measurements of tobacco smoke con stituents in aircraft and other closed environments reveals that being seated in the non-smoking section of an aircraft does not provide effective protection against the involuntary inhalation of tobacco smoke. In certain instances, smoke concentrations higher than the average level in the smoking section may be present. Particularly in the borderline area between the smoking and non smoking sections (ie, one to three rows in front of or behind a smoking section), levels may be equal to or above those in the smoking section. This is particularly the case where ventilation makes partial use of recirculated air. Pollutant concentrations from tobacco smoke aboard aircraft in smoking sec tions and the bordering non-smoking sections in part clearly exceed the levels in other indoor situations where smoking takes place. Levels in the non-smoking sections of aircraft (beyond the areas bordering smoking sections) are similar to those in homes where smoking takes place. In the majority of studies, health risks associated with passive smoking have been found in persons living in smokers' households.

Toxicology of Volatile Organic Compounds in Indoor Air and Strategy for Further Research

Indoor air is a variable complex mixture of chemicals and airborne particles. Volatile organic compounds (VOC) constitute a major group of indoor air pollutants encompassing diverse chemicals such as aldehydes, terpenes. and aromatic, aliphatic and halogenated hydrocarbons. Of many of these compounds, our knowledge of their possible health effects is very limited. To improve the situation, combined information should be assembled about the nature of VOC, the degree of human exposure, the number of people exposed and, most importantly, the toxicology of VOC. Evidence of carcinogenic potential in animals is convincing for formaldehyde and acetaldehyde vapor. Formaldehyde carcinogenesis is a highdose phenomenon with a determining role for cytolethahty. This may also be true for acetaldehyde carcinogenesis, but further studies are needed to verify this assumption. Being a reactive, potent DNA-protein cross-linker and a major indoor air contaminant, acrolein should be tested in a long-term rat inhalation carcinogenicity study. Studies with combinations of aldehydes, including superimposed peak exposures, would contribute a great deal to a realistic health hazard assessment of this class of compounds. Short-term inhalation toxicity studies, including toxicokinetics of a number of relevant terpenes. are deemed desirable to find out whether this category of chemicals forms a priority indoor air issue. Benzene is a human carcinogen at high hemotoxic exposure levels. There is evidence to suggest that at non-hemotoxic exposure concentrations the risk of leukemia decreases more than proportionally, soon becoming negligibly small. In comparison with benzene, detoxification of toluene and xylene is rapid which may explain the non-carcinogenicity of these benzene homologues. In nonoccupational situations, indoor air hexane concentrations are orders of magnitude lower than exposure levels associated with clinically overt neuropathy. Therefore, hexane is not regarded as an indoor air pollutant of major concern. Main elements of a strategy for further toxicological studies of (VOC in) indoor air include: (a) setting of priorities for testing individual compounds, classes of compounds and combinations of compounds; (b) identification of the type of information to be assembled; (c) prediction and experimental verification of synergism or additiveness between compounds; (d) application of biologically or physiologically based pharmacokinetic modelling to optimize extrapolation of toxicodynamic data obtained in fixed-time animal experiments to low-dose/long-time human situations, and (e) (geno)toxicity testing of relevant existing combinations of chemicals (e.g. 20 to 30) at concentrations of, e.g., a factor 3 or 10 higher than those occurring in indoor air. Studies along the lastmentioned practical line may be very helpful in narrowing down the number of indoor situations of real health concern.

Comparison of Insect Species Associated with Decomposing Remains Recovered Inside Dwellings and Outdoors on the Island of Oahu, Hawaii

A comparison of insects collected from 35 cases of decomposing remains on the island of Oahu, Hawaiian Islands (14 from indoor situations and 21 from outdoors), yielded a total of 22 species of insects in 3 orders and 12 families. Of these, five species were recovered in both indoor and outdoor situations. Remains recovered indoors had a greater variety of Diptera larvae associated with them, while remains discovered outdoors had a greater variety of Coleoptera species present. Some species of insects were restricted to remains discovered indoors, while others were found only associated with remains in outdoor situations. Knowledge of the species of insects associated with different habitats may serve to provide information concerning the history of the remains.

94 GHz three-dimensional imaging radar sensor for autonomous vehicles

The authors report on using millimeter-wave images for real-time vehicle guidance. For application in the field of autonomous locomotion, the main advantage of this sensor concept is direct access to range and velocity information. System design and imaging results of a multitask 94-GHz pulse Doppler radar with 25-cm radial and 1.5 degrees angular resolution are discussed. To point out specific millimeter-wave scattering phenomena, various radar images of typically structured indoor situations are presented. Extraction of information from sensor data, for example, obstacle detection, is demonstrated by radar image processing.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Exposure to carbon monoxide, respirable suspended particulates and volatile organic compounds while commuting by bicycle

A portable air sampling system has been used to assess exposures to various substances while commuting by bicycle in an urban area. The major source of pollutants in this situation is motor vehicle exhaust emissions. Carbon monoxide, measured by electrochemical detection, was found at peak concentrations in excess of 62 ppm, with mean values over 16 individual 35-mm journeys being 10.5 ppm. Respirable suspended particulates, averaged over each journey period, were found at higher concentrations (mean 130 {mu}g m{sup {minus}3}) than would be expected in indoor situations. Mean exposure to benzene (at 56 {mu}g m{sup {minus}3}) and other aromatic volatile organic compounds was also relatively high. The influence of wind conditions on exposure was found to be significant. Commuting exposures to carbon monoxide, respirable suspended particulates, and aromatic VOCs were found to be higher than exposures in a busy high street and on common parkland.

Heat stress assessment in the industrial facilities (A case study)

Abstract Heat stress assessment in the work place is of vital importance for the well‐being of industrial workers and consequently the optimum performance of the industrial facilities. A methodology for determining the heat stress in a large number of factories is presented. The Wet Bulb Globe Temperature (WBGT) index was adapted in this study. Detailed strategy is given for proper and efficient assessment. The data were carefully analyzed in the light of set international standards and the degree of compliance of the facilities surveyed. Furthermore other factors such as the type of industry, air‐conditioning and outdoor conditions which affect the indoor situation, were also investiated.

Retrieving 3D information from video for robot control and surveillance

A technique has recently been developed at Roke Manor Research Ltd. for recovering three-dimensional (3D) information from conventional video data. This is based on matching features in a scene observed from different viewpoints, either as a result of intrinsic camera or object motion or through the use of multiple cameras. The technique has been examined as a means of supplying guidance information to a robot manipulator and an autonomous vehicle. Results indicate that the method is capable of recognising basic surface structure in a variety of indoor and outdoor situations. The essential elements of the technique are described and a real-time system implementation is outlined. A surveillance application is also discussed whereby the derived 3D representation can be exploited in a data compression device to communicate concise 3D information to a remote operator or observer.

Audibility of some specific public-address warning signals in typical environmental noise situations

The scope of the explorative study reported here is to investigate the audibility of different public-address warning signals (existing and new) in different environmental noise situations. Three outdoor situations as well as three indoor situations have been simulated with noise signals of different spectral and temporal patterns. Seven warning signals and—for comparison—a steady-state 1200-Hz tone were used. Indoor listening was allowed for by means of electronic filtering of the warning signals. Four subjects (two female, two male) aged 12 to 42 years took part in the psychoacoustic experiments, which were performed under laboratory conditions in an anechoic chamber. The results suggest a strong interdependence of the spectral distributions of the warning signals and of the environmental noise signals. In addition, the temporal structure of the environmental noise was found to influence the audibility of the warning signal in the sense that a steady-state environmental noise represents the ‘worst case’.

Speech intelligibility of normal listeners and persons with impaired hearing in traffic noise

Speech intelligibility (PB words) in traffic-like noise was investigated in a laboratory situation simulating three common listening situations, indoors at 1 and 4 m and outdoors at 1 m. The maximum noise levels still permitting 75% intelligibility of PB words in these three listening situations were also defined. A total of 269 persons were examined. Forty-six had normal hearing, 90 a presbycusis-type hearing loss, 95 a noise-induced hearing loss and 38 a conductive hearing loss. In the indoor situation the majority of the groups with impaired hearing retained good speech intelligibility in 40 dB(A) masking noise. Lowering the noise level to less than 40 dB(A) resulted in a minor, usually insignificant, improvement in speech intelligibility. Listeners with normal hearing maintained good speech intelligibility in the outdoor listening situation at noise levels up to 60 dB(A), without lip-reading (i.e., using non-auditory information). For groups with impaired hearing due to age and/or noise, representing 8% of the population in Sweden, the noise level outdoors had to be lowered to less than 50 dB(A), in order to achieve good speech intelligibility at 1 m without lip-reading.

Speech Intelligibility in and Speech Interference Levels of Traffic Noise in Hearing-Impaired and Normal Listeners

Speech intelligibility (phonetically balanced monosyllables = PB words) in traffic-like noise (random noise) as well as the speech interference levels (75% intelligibility) of this noise were investigated in three common listening situations, two indoors and one outdoors. A total of 279 persons were examined; 56 had normal hearing, 90 a presbycusic-type hearing loss, 95 noise-induced hearing loss, and 38 conductive hearing loss. In the indoor situation the hearing-impaired groups mainly retained their intelligibility in 40 dBA. Lowering of the noise level to less than 40 dBA resulted in only a minor, mostly insignificant improvement in speech intelligibility. Normal-hearing listeners maintained good speech intelligibility in the outdoor listening situation with noise levels up to 60 dBA, without lip-reading. For hearing-impaired groups, representing more than 1/2 million (8% of the population) people in Sweden, with hearing loss due to age and/or noise, the noise level outdoors must be lowered to 45 dBA in order to achieve good speech intelligibility at 1 m, without lip-reading.

The production of constant high potential with moderate power capacity

In spite of the remarkable development of technology, most studies for building energy controls to evaluate or estimate the energy performance have not accurately reflected actual building’s energy consumption patterns. For this issue, several techniques, such as simulation and calibration, comprehensive survey system, smart metering, and commissioning, have been attempted.However, in most studies, some factors in thermal systems derived from occupant behavior were perceived as fixed objects, and the factors were converted into simple numbers as parts of inputs into simulation templates. There was lack of studies on considerations that unpredictable responses derived from human anti-logic or common sense could deteriorate energy efficiency in theoretical analyses even though the systems were properly operated.This research proposes integrated energy supply models based on artificial intelligence responding to anti-logic or common sense that can reduce machine’s energy saving effects. By use of design scenarios assuming some unusual situations, a decision making model determines the extent to which the cause of the abnormal situations are associated with the occupant behavior. After the five-step phases in the decision making model, the actual outputs of the energy supply model for the buildings are determined, and the reciprocal communication between the thermal and decision making models mitigates thermal dissatisfaction and energy inefficiency. Comparative analysis describes the decision making model’s effectiveness that it improves thermal comfort levels by about 2.5% for an office building and about 10.2% for residential buildings, and that it reduces annual energy consumption by about 17.4% for an office building and about 25.7% for residential buildings. As a consequence, the integrated energy control model has advantages that it noticeably improves thermal comfort and energy efficiency, and that it properly respond to abnormal and abrupt indoor situations derived from human anti-logic or common sense.