Abstract
For the assessment of personal exposure, information about the concentration of pollutants when people are in given indoor environments (occupancy time) are of prime importance. However this kind of data frequently is not reported. The aim of this study was to assess differences in particle characteristics between occupancy time and the total monitoring period, with the latter being the most frequently used averaging time in the published data. Seven indoor environments were selected in Sweden and Finland: an apartment, two houses, two schools, a supermarket, and a restaurant. They were assessed for particle number and mass concentrations and number size distributions. The measurements using a Scanning Mobility Particle Sizer and two photometers were conducted for seven consecutive days during winter in each location. Particle concentrations in residences and schools were, as expected, the highest during occupancy time. In the apartment average and median PM2.5 mass concentrations during the occupancy time were 29% and 17% higher, respectively compared to total monitoring period. In both schools, the average and medium values of the PM2.5 mass concentrations were on average higher during teaching hours compared to the total monitoring period by 16% and 32%, respectively. When it comes to particle number concentrations (PNC), in the apartment during occupancy, the average and median values were 33% and 58% higher, respectively than during the total monitoring period. In both houses and schools the average and median PNC were similar for the occupancy and total monitoring periods. General conclusions on the basis of measurements in the limited number of indoor environments cannot be drawn. However the results confirm a strong dependence on type and frequency of indoor activities that generate particles and site specificity. The results also indicate that the exclusion of data series during non-occupancy periods can improve the estimates of particle concentrations and characteristics suitable for exposure assessment, which is crucial for estimating health effects in epidemiological and toxicological studies.
Highlights
In numerous epidemiological studies, outdoor fine particulate matter PM2.5 has been associated with cardiopulmonary diseases and increased mortality (Pope and Dockery, 2006)
The results indicate that the exclusion of data series during non-occupancy periods can improve the estimates of particle concentrations and characteristics suitable for exposure assessment, which is crucial for estimating health effects in epidemiological and toxicological studies
Recent studies show that about 60% of exposure to ultrafine particles (
Summary
Outdoor fine particulate matter PM2.5 (particles with diameter smaller than 2.5 mm) has been associated with cardiopulmonary diseases and increased mortality (Pope and Dockery, 2006). Poor correlations have been found between outdoor PM2.5 and personal exposure, which initiated a debate whether the outdoor PM is a good surrogate for exposure to PM (Meng et al, 2005; Wilson and Brauer, 2006) This is because apart from outdoor PM sources, indoor, work related, in-vehicle sources and personal activities contribute to personal exposure. Many indoor sources generate particles in amounts that exceed levels observed outdoors by far (He et al, 2004; Long et al, 2000). It may be that particles generated indoors have different health effects than those of outdoor origin. Epidemiological studies on population representative scale, so far have been exclusively based on outdoor particle characteristics. This is mainly due to lack of population representative data on indoor particle characteristics suitable for epidemiological studies
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
