Types Of Indoor Environments Research Articles

Wintertime indoor air levels of PM 10, PM 2.5 and PM 1 at public places and their contributions to TSP

From 26 October 2002 to 8 March 2003, particulate matter (PM) concentrations (total suspended particles [TSP], PM 10, PM 2.5 and PM 1) were measured at 49 public places representing different environments in the urban area of Beijing. The objectives of this study were (1) to characterize the indoor PM concentrations in public places, (2) to evaluate the potential indoor sources and (3) to investigate the contribution of PM 10 to TSP and the contributions of PM 2.5 and PM 1 to PM 10. Additionally, The indoor and outdoor particle concentrations in the same type of indoor environment were employed to investigate the I/O level, and comparison was made between I/O levels in different types of indoor environment. Construction activities and traffic condition were the major outdoor sources to influence the indoor particle levels. The contribution of PM 10 to TSP was even up to 68.8%, while the contributions of PM 2.5 and PM 1 to PM 10 were not as much as that of PM 10 to TSP.

Source characterization of BTEX in indoor microenvironments in Hong Kong

Levels of benzene, toluene, ethylbenzene and the xylenes (BTEX) in different indoor microenvironments such as offices, homes, schools, shopping malls and restaurants were investigated in Hong Kong. Different indoor environments including six offices, six homes, six air-conditioned classrooms, six shopping malls and four restaurants were selected in Hong Kong for indoor and outdoor BTEX measurement. This study is aimed to determine qualitatively or semi-quantitatively sources of BTEX. Source identification is possible by determining the indoor/outdoor ( I/ O) concentration ratio. An I/ O ratio>1 was considered as an indicator for indoor sources. For BTEX in different indoor environments except for schools, some of the pollutants were dominated by outdoor sources while others mainly originated from indoor sources. In schools, however, the BTEX predominantly originated from outdoor sources. The potential sources of BTEX in indoor environments were also identified by using principal component analysis and nonparametric Kruskal–Wallis test. The number of variables was reduced to two and one new factors for indoor and outdoor data, respectively. These factors were related to certain source characteristics. It is shown that the type of land use, the use of printers, the traffic condition, the cooking style, the type of gas stove, smoking and internal decoration strongly influence the indoor concentrations of BTEX ( p<0.05). Significant difference of BTEX concentrations in the five types of indoor environments were also observed ( p<0.05).

Investigation of indoor air quality at residential homes in Hong Kong—case study

Indoor air quality (IAQ) has been a matter of public concern in Hong Kong. Recently, the Hong Kong Government has recognized the potential risk and problems related to indoor air pollution, and it is striving to establish IAQ objectives for different types of indoor environments. This study attempts to provide more information about the present IAQ of local resident flats. Air pollutants measured in this study included carbon dioxide (CO 2), respirable suspended particulate matter (PM 10), formaldehyde (HCHO), volatile organic compounds (VOCs) and airborne bacteria. The results of this study indicate that the 8-h average concentrations of CO 2 and PM 10 in the domestic kitchens investigated were 14% and 67% higher than those measured in the living rooms. The indoor air pollution caused by PM 10 was more serious in domestic kitchens than in living rooms as almost all of the kitchens investigated had higher indoor levels of PM 10. The majority of the domestic living rooms and kitchens studied had average concentrations of airborne bacteria higher than 500 CFU/m 3. The mean total bacteria count recorded in kitchens was greater than that obtained in living rooms by 23%. In homes where occupants smoke, the negative impact of benzene, toluene and m, p-xylene on the IAQ was greatly enhanced. The use of liquefied petroleum gas (LPG) stove has more significant impact on indoor VOCs than the use of cooking stoves with natural gas as cooking fuel.

ETS-RSP Particulate Marker Factors: Variation in Published Factors and Application to ETS Data from Two Types of Indoor Environments

Environmental tobacco smoke (ETS) is an indoor air pollutant that causes adverse health effects for exposed non-smokers. To measure the ETS concentration particulate tobacco smoke components are identified and are referred to as ETS markers named ultraviolet particulate matter (UVPM), fluorescent particulate matter and solanesol particulate matter. To determine the contribution of ETS to indoor air pollution empirically derived ETS marker factors are applied. The factors represent a ratio of ETS marker to total respirable suspended particles (RSP) collected under controlled experimental conditions. The published ETS marker factors for UK cigarettes varied and when applied to smoking and non-smoking household and public house data produced significantly different data sets (p < 0.05). Non-tobacco sources for UVPM compounds contributed to and overestimated the ETS-UVPM concentration with respect to RSP. This occurred when the published UVPM factors were applied and the predominant source of UVPM was not tobacco. The ETS factors produced acceptable results with respect to total RSP collected when tobacco was the predominant source of RSP, as seen by data collected in public houses.

ETS-RSP Particulate Marker Factors: Variation in Published Factors and Application to ETS Data from Two Types of Indoor Environments

Environmental tobacco smoke (ETS) is an indoor air pol lutant that causes adverse health effects for exposed non-smokers. To measure the ETS concentration partic ulate tobacco smoke components are identified and are referred to as ETS markers named ultraviolet particulate matter (UVPM), fluorescent particulate matter and sola nesol particulate matter. To determine the contribution of ETS to indoor air pollution empirically derived ETS marker factors are applied. The factors represent a ratio of ETS marker to total respirable suspended particles (RSP) collected under controlled experimental condi tions. The published ETS marker factors for UK ciga rettes varied and when applied to smoking and non- smoking household and public house data produced sig nificantly different data sets (p &lt; 0.05). Non-tobacco sources for UVPM compounds contributed to and over estimated the ETS-UVPM concentration with respect to RSP. This occurred when the published UVPM factors were applied and the predominant source of UVPM was not tobacco. The ETS factors produced acceptable re sults with respect to total RSP collected when tobacco was the predominant source of RSP, as seen by data col lected in public houses.

Volatile organic compounds in indoor environments in Mumbai, India

Air samples, representing different types of indoor environments, were collected and analyzed for eight hydrocarbons namely, n-hexane, benzene, heptane, toluene, p- and o-xylene, ethyl benzene and n-decane using a cryogenic preconcentration system and a gas chromatograph with a flame-ionization detector. Simultaneous outdoor samples were also collected to determine indoor to outdoor (I/O) ratios for every compound at each location. In all, seven different types of indoor environments were investigated for VOC levels. Toluene concentration levels were found to be high in a hall which was recently renovated. The indoor environment of a kitchen in which a kerosene stove was used and smoker’s rooms showed high levels of benzene. The concentrations of VOCs during painting were found to be high and the levels of VOCs depended on the type of paint used. The study revealed that the indoor concentrations of selected VOCs on occasions could be significantly high due to various sources. The data presented here can be useful in developing air quality standards for indoor air.