Low Flow Rate Sharp Cut Impactors for Indoor Air Sampling: Design and Calibration

137

Fine particle mass (PM 2.5 ), black smoke (BS) and particle number concentration (NC) were measured simultaneously indoors and outdoors at an urban location in Erfurt, Germany. Measurements were conducted during 2-month periods in summer and winter. Different ventilation modes were applied during each measurement period: windows closed; windows opened widely for 15 min twice per day; windows and door across the room opened widely for 5 min twice per day and windows tilted open all day long. The lowest indoor/outdoor (I/O) ratios for all pollutants were found for closed windows, whereas the ratios for ventilated environments were higher. For closed windows, the I/O ratios for PM 2.5 are larger than the corresponding values for BS and NC (0.63 vs. 0.44 or 0.33, respectively) probably due to lower penetration factors for particles sizes o500 nm and higher deposition rates for ultrafine particles (o100 nm). The largest differences for the I/O ratios between closed and tilted windows were found for NC (0.33 vs. 0.78). The indoor and outdoor levels of PM 2.5 and BS were strongly correlated for all ventilation modes. The linear regression models showed that more than 75% of the daily indoor variation could be explained by the daily outdoor variation for those pollutants. However, the correlation between indoor and outdoor NC for ventilation twice a day was weak. It indicates that rapid changes of the air exchange rates during the day may affect the correlation and regression analysis of NC indoor and outdoor concentrations. This effect was not observed for PM 2.5 or BS. This study shows the importance of the indoor air aerosol measurements for health effects studies and the need for more research on I/O transport mechanisms for NC.

Section: Instrumentationmentioning

confidence: 99%

Relationship between indoor and outdoor levels of fine particle mass, particle number concentrations and black smoke under different ventilation conditions

Cyrys

Pitz

Bischof

et al. 2004

137

“…Indoor and outdoor PM 2.5 and PM 10 samples were collected using one -stage Harvard Impactors ( HIs ) operated at 10 liters per minute (LPM ) ( Marple et al, 1987;Lioy et al, 1988 ), equipped with 41 -mm Teflon filters (Gelman R2PJ041) . Personal PM 2.5 and PM 10 exposure samples were collected using modified PEMs ( Thomas et al, 1993 ), which are portable one -stage impactors that capture particles on 37-mm Teflon filters ( Gelman R2PJ037 ).…”

Section: Particulate Matter Samplesmentioning

confidence: 99%

Relationships among personal, indoor, and outdoor fine and coarse particle concentrations for individuals with COPD

Rojas-Bracho

Suh

Koutrakis

2000

149

This study characterizes the personal, indoor, and outdoor PM 2.5 , PM 10 , and PM 2.5 ± 10 exposures of 18 individuals with chronic obstructive pulmonary disease ( COPD ) living in Boston, MA. Monitoring was performed for each participant for six consecutive days in the winters of 1996 or 1997 and for six to twelve days in the summer of 1996. On each day, 12 -h personal, indoor, and outdoor samples of PM 2.5 and PM 10 were collected simultaneously. Home characteristic information and time ± activity patterns were also obtained. Personal exposures were higher than corresponding indoor and outdoor concentrations for all particle measures and for all seasons, except for winter indoor PM 2.5 ± 10 levels, which were higher than personal and outdoor levels. Higher personal exposures may be due to the proximity of the individuals to particle sources, such as cooking and cleaning. Indoor concentrations were associated with both outdoor concentrations and personal exposures ( as determined by individual least square regression analyses ) , with associations strongest for PM 2.5 . Indoor PM 2.5 concentrations were significantly associated with outdoor and personal levels for 12 and 15 of the 17 individuals, respectively. Both the strength and magnitude of the associations varied by individual. Also, personal PM 2.5 , but not PM 2.5 ± 10 , exposures were associated with outdoor levels, with 10 of the 17 subjects having significant associations. The strength of the personal ± outdoor association for PM 2.5 was strongly related to that for indoor and outdoor levels, suggesting that home characteristics and indoor particulate sources were key determinants of the personal ± outdoor association for PM 2.5 . Air exchange rates were found to be important determinants of both indoor and personal levels. Again, substantial interpersonal variability in the personal ± outdoor relationship was found, as personal exposures varied by as much as 200% for a given outdoor level.

“…Previous studies comparing nephelometer results to PM 2.5 impactor measurements indicate strong correlations ( 0.81< R 2 <0.96 ) when sampling kitchens fuelled with biomass in Mexico, in homes with wood stoves and ETS in rural British Columbia (Brauer, 1995;Brauer et al, 1996 ) and in ambient air (Waggoner and Weiss, 1980;Koenig et al, 1993;Thomas and Gebhart, 1994 ). In the present study, the performance of a nephelometer (Radiance Research Model M903, Seattle, WA ) for a large number of cooking and ETS sources was compared with mass concentrations determined using two different particulate mass concentration measurement techniques: a PM 2.5 Harvard Impactor (Marple et al, 1987 ) and a piezobalance (TSI Model 8510, St. Paul, MN ) equipped with a PM 3.5 impactor.…”

Section: Introductionmentioning

confidence: 99%

Assessment of indoor fine aerosol contributions from environmental tobacco smoke and cooking with a portable nephelometer

Bräuer

Hirtle

Lang

et al. 2000

Personal monitoring studies have indicated that environmental tobacco smoke ( ETS ) and cooking are major indoor particulate sources in residential and nonindustrial environments. Continuous monitoring of fine particles improves exposure assessment by characterizing the effect of time -varying indoor sources. We evaluated a portable nephelometer as a continuous monitor of indoor particulate levels. Simultaneous sampling with the nephelometer and PM 2.5 impactors was undertaken to determine the relationship between particle light scattering extinction coefficient ( sp ) and particle mass concentration in field and environmental chamber settings. Chamber studies evaluated nephelometer measurements of ETS and particles produced from toasting bread and frying foods. Field measurements were conducted in 20 restaurants and bars with different smoking restrictions, and in five residential kitchens. Additional measurements compared the nephelometer to a different mass measurement method, a piezobalance, in a well -characterized residence where various foods were cooked and ETS was produced. Since the piezobalance provides 2 -min average mass concentration measurements, these comparisons tested the ability of the nephelometer to measure transient particle concentration peaks and decay rate curves. We found that sp and particle mass were highly correlated ( R 2 values of 0.63 ± 0.98 ) over a large concentration range ( 5 ± 1600 g / m 3 ) and for different particle sources. Piezobalance and gravimetric comparisons with the nephelometer indicated similar sp vs. mass slopes ( 5.6 and 4.7 m 2 / g for piezobalance and gravimetric comparisons of ETS, respectively ) . Somewhat different sp vs. particle mass slopes ( 1.9 ± 5.6 m 2 / g ) were observed for the different particle sources, reflecting the influence of particle composition on light scattering. However, in similar indoor environments, the relationship between particle light scattering and mass concentration was consistent enough to use independent nephelometer measurements as estimates of short -term mass concentrations. A method to use nephelometer measurements to determine particulate source strengths is derived and an example application is described.