Personal and indoor/outdoor nitrogen dioxide exposure assessments of 23 homes in Taiwan

A pilot study of indoor air quality in screen golf courses

The aims of this study were to provide basic data for determining policies on air quality for multi-user facilities, including the legal enrollment of the indoor air quality regulation as designated by the Ministry of Environment, and to establish control plans. To this end, concentrations of ten pollutants (PM10, carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), formaldehyde (HCHO), total volatile organic compounds (TVOCs), radon (Rn), oxone (O3), total bacteria counts (TBC), and asbestos) in addition to nicotine, a smoking index material used to determine the impact of smoking on the air quality, were investigated in indoor game rooms and lobbies of 64 screen golf courses. The average concentration of none of the ten pollutants in the game rooms and lobbies of screen golf courses was found to exceed the limit set by the law. There were, however, pollutant concentrations exceeding limits in some screen golf courses, in order to establish a control plan for the indoor air quality of screen golf courses, a study on the emission sources of each pollutant was conducted. The major emission sources were found to be facility users' activities such as smoking and the use of combustion appliances, building materials, and finishing materials.

Indoor air pollution and childhood asthma: variations between urban and rural areas

Health effects of indoor pollution have been investigated overall in urban areas. To compare the potential effect of home air pollutants on asthma in urban and rural houses, two case-control populations, composed of children living in the city (32 asthmatics and 31 controls) and in the countryside (24 asthmatics and 27 controls) were included. During 1 week, nitrogen dioxide, fine particles, and volatile organic compounds (formaldehyde, acetaldehyde, benzene, toluene, ethylbenzene, and xylenes) were assessed at home. Urban dwellings were found to be more polluted than rural ones, with concentrations up to two times higher. In the whole population, exposure to acetaldehyde and toluene was significantly associated with a higher risk of asthma. In the urban population, the association with toluene was significant in children studied during winter, and with toluene, xylenes, and ethylbenzene when cases were restricted to current asthmatics. In rural settings, a relationship between asthma and formaldehyde exposure was observed (OR = 10.7; 95% CI 1.69-67.61). Our findings suggest that daily continuous exposures to pollutants may be implicated in asthma, even in the case of low exposure, as those found in rural areas. Our results could also indicate a specific effect of indoor pollution in the rural environment.

PRACTICAL IMPLICATIONS

Everyday exposure to indoor pollution was associated with a higher risk of childhood asthma. These findings suggest that even at low concentrations, pollutants could be implicated in asthma and reinforce the importance of establishing guideline values to improve indoor air quality by limiting sources or by optimizing ventilation. Specific effects could occur in rural environments where pollution differs from urban area.

Factors affecting individual exposure to NO2 in Genoa (northern Italy)

The individual exposure to nitrogen dioxide (NO2) of 89 volunteers living in Genoa, a large port city of northern Italy, was investigated with personal passive diffusion tubes in February-March 2000. The data were related to NO2 concentration in the kitchen and bedroom as measured by static samplers. Volunteers included students, workers and housewives living in three areas of Genoa differing by street traffic and industrial plant location. The kitchen samples showed higher (47.00+/-16.5 microg/m3) NO2 concentrations than those from the bedroom (24.78+/-9.8 microg/m3); overall indoor NO2 concentrations were lower in the Eastern area of Genoa, where outdoor pollution is lower. Students were the volunteer group with the lowest exposure rate (24.9+/-7.8 microg/m3 vs. 44.3+/-10.1 microg/m3 for workers and 40.0+/-13.4 microg/m3 for housewives). This difference is related to the fact that students spend more time indoors, where pollution levels are lower. The main household characteristics which were shown to affect personal NO2 exposure were (a) the presence of a chimney equipped with an active aspiration device in the kitchen and (b) the heating system.

Sources and concentrations of indoor nitrogen dioxide in Hamburg (west Germany) and Erfurt (east Germany)

Here we report indoor and outdoor concentrations of NO2 for Erfurt and Hamburg and assess the contribution of the most important indoor sources (e.g. the presence of gas cooking ranges, smoking) and outdoor sources (traffic exhaust emissions). We examined the relative contribution of the different sources of NO2 to the total indoor NO2 levels in Erfurt and Hamburg. NO2 indoor concentrations in Hamburg were slightly higher than those in Erfurt (i.e. living room: 15 microg m(-3) for Erfurt and 17 microg m(-3) for Hamburg). A linear regression model including the variables, place of residence, season and outdoor NO2 levels, location of the home within the city, housing and occupant characteristics accounted for 38% of the NO2 variance. The most important predictors of indoor NO2 concentrations were gas in cooking followed by other characteristics, such as ventilation or outdoor NO2 level. Residences in which gas was used for cooking, or in which occupants smoked, had substantially higher indoor NO2 concentrations (41 or 18% increase, respectively). An increase in the outdoor NO2 concentration from the 25th to the 75th-percentile (17 microg m(-3)) was associated with a 33% increase in the living room NO2 concentration. Multiple regression analysis for both cities separately illustrated that use of gas for cooking was the major indoor source of NO2. This variable caused a similar increase in the indoor NO2 levels in each city (43% in Erfurt and 47% in Hamburg). However, outdoor sources of NO2 (motor vehicle traffic) contributed more to indoor NO2 levels in Hamburg than in Erfurt.

Asthma and the home environment

Recent years have seen a global increase in asthma prevalence. This has coincided with modifications to the home environment resulting in changes to the indoor air quality. This article considers the links between indoor pollution and asthma. Exposure to a range of substances is examined. Airborne allergens such as those from house dust mites may be important. Pollution from particulate materials associated with combustion and smoking is discussed, as is the role of chemical vapors and gases including nitrogen dioxide, sulfur dioxide, and volatile organic compounds. The efficacy of various environmental controls to limit the impact of these pollutants is explored.