Relation between particle mass and number for submicrometer airborne particles

Morawska, Lidia; Johnson, Graham R.; Ristovski, Zoran; Agranovski, Victoria

doi:10.1016/s1352-2310(98)00433-6

Cited by 68 publications

(52 citation statements)

References 14 publications

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“…In terms of number per volume, particles of Aitken and accumulation modes were predominant in the entire particle group with fractions of 62-66% and 25-30%, respectively, however, nucleation mode particles accounted for only about 7-9% and coarse particles were negligible 0.1%. Total particle surface and volume concentrations were calculated by integrating the number size distributions of size-resolved particles assuming particle sphericity and density 1.0 g/cm 3 , which is reasonable and comparable to 1.0-1.5 g cm -3 in Riverside, California and 1.2-1.8 g/cm 3 in Queensland, Australia (Morawska et al, 1999;Spencer et al, 2007), and their averages were 6.6-7.7 × 10 2 µm 2 /cm 3 and 54-66 µm 3 /cm 3 for autumn and winter. Accumulation mode particles dominated exceeding 80% of the total particle surface area concentration, and contributed about 30-45% of the total particle volume concentration.…”

Section: Particle Size Spectramentioning

confidence: 82%

Aerosol Size Spectra and Particle Formation Events at Urban Shanghai in Eastern China

Cheng

Zhang

et al. 2012

Aerosol Air Qual. Res.

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Aerosol number size distributions between 10 nm and 10 µm were measured from October 2008 to February 2009 in Shanghai, China. The average particle number, surface and volume concentrations were 1.3 × 10 4 1/cm 3 , 6.4 × 10 2 µm 2 /cm 3 and 64 µm 3 /cm 3 , respectively. Aitken particles dominated the total number of particles, and accumulated particles were the greatest contributor to particle surface area. Particle number size distributions could be characterized by multi-lognormal functions. The average number size distributions of aerosols revealed a clear diurnal pattern of two peaks within 30-60 nm corresponding to the morning and afternoon traffic rush hours. All size particles had two peaks in mean number concentrations during the rush hours, and 10-20 nm and 20-50 nm particles had one additional peak in late morning. The new particle formation events were found on four days out of 73. The apparent formation rates varied from 0.2 to 0.5 cm 3 /s, and the growth rates of newly formed particles were 3.3-5.5 nm/h. Overall, the new particle formation events had a significant impact on particle size spectra in the nucleation and Atiken modes, but insignificant effects on particle surface and volume concentrations.

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Section: Particle Size Spectramentioning

confidence: 82%

Aerosol Size Spectra and Particle Formation Events at Urban Shanghai in Eastern China

Cheng

Zhang

et al. 2012

Aerosol Air Qual. Res.

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“…Literature studies on monitoring ambient aerosol, in fact, estimated particle density in the size range 1.5-1.8 g cm −3 (Morawska et al 1999a;Sioutas et al 2000;Shen et al 2002;Fine et al 2004;Barone et al 2006;Buonanno et al 2009). The density has to be directly measured in every aerosol characterization.…”

Section: Pm Uncertainty Budget Using Smpsmentioning

confidence: 99%

“…The mass concentrations obtained through the APS results quite similar to those obtained using the gravimetric method. Finally, in Morawska et al (1999a) the method of experimental correlation of particle mass and number using a TEOM and a SMPS operating in the submicrometer size ranges was developed and validated using two aerosols of known density. The results indicate that when the particle density is constant the correlation is strong.…”

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confidence: 99%

Uncertainty Budget of the SMPS–APS System in the Measurement of PM₁, PM_2.5, and PM₁₀

Buonanno

Dell’Isola

Stabile

et al. 2009

Aerosol Science and Technology

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The effects of particulate matter on environment and public health have been widely studied in recent years. In spite of the presence of numerous studies about this topic there is no agreement on the relative importance of the particles' size and origin with respect to health effects among researchers. Nevertheless, air quality standards are moving, as the epidemiological attention, towards greater focus on the smaller particles. The most reliable method used in measuring particulate matter (PM) is the gravimetric method since it directly measures PM concentration, guaranteeing an effective traceability to international standards. This technique, however, neglects the possibility to correlate short term intraday atmospheric parameter variations that can influence ambient particle concentration and size distribution as well as human activity patterns. Besides, a continuous method to determine PM concentrations through the measurement of the number size distribution is the system constituted by a Scanning Mobility Particle Sizer (SMPS) and an Aerodynamic Particle Sizer (APS). In this article, the evaluation of the uncertainty budget in measuring PM through the SMPS-APS system, as well as a metrological comparison with the gravimetric reference method in order to analyze the compatibility, was carried out and applied with reference to an experimental campaign developed in a rural site. This choice allowed to assume the hypothesis of spherical particle morphology. The average PM 10 , PM 2.5 , and PM 1 uncertainties obtained for the SMPS-APS system are equal to 27%, 29%, and 31%, respectively. Here the principle influence parameter is the particle density that has to be directly measured with low uncertainty in order to reduce the PM uncertainty.

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“…Absolute individual RTS contribution was calculated by subtracting the last background particle concentration from particle concentration after each smoker's entrance, expressed in particle/m 3 , and multiplied by 33.2 m 3 , the volume of the room. Ambient particulate matter (2.5) concentrations (mg/m 3 ) were calculated by transforming the number of particles/l of the diameters 0.3-1.0, 1.01-2.00, 2.01-3.0 mm into mass, according to the method described by Morawska et al, 13 assuming a mean (SD) density of 1.18 (0.06) g/cm 3 for ETS. Figure 1 Example of real-time measurement of 0.3-1.0 mm particle concentration in the exhaled breath during ambient air tidal breathing.…”

Section: Calculation Of Contribution Of Rts To Indoor Air Pollutionmentioning

confidence: 99%

Residual tobacco smoke: measurement of its washout time in the lung and of its contribution to environmental tobacco smoke

et al. 2007

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Background: Tobacco smoking entails inhaling millions of fine particles with each puff, and it is intuitive that after smoking a cigarette it will take a certain time to washout residual tobacco smoke (RTS) from the lungs with subsequent breaths. Objectives: To study the washout time of 0.3-1.0 mm particles after the last puff in 10 volunteer smokers by using equipment capable of measuring particle concentration in real time in the exhaled air. Result: Mean (standard deviation (SD)) lung RTS washout time was 58.6 (23.6) s, range 18-90 s, and corresponded to 8.7 (4.6) subsequent breathings. The contribution of individual and overall RTS to indoor pollution was calculated by subtracting incremental background particle concentration from room concentration after 10 consecutive re-entries of smokers after the last puff into a room of 33.2 m 3 , with an air exchange rate per hour in the range of 0.2-0.4. Mean (SD) individual RTS contribution consisted of 1402 (1490) million particles (range 51-3611 million), whereas RTS increased room 0.3-1.0 mm particle concentration from a baseline of 22 283 particles/l to a final room concentration of 341 956 particles/l, corresponding to a total increase in particulate matter (2.5) from a background of 0.56 up to 3.32 mg/m 3 . Conclusion: These data reveal a definite although marginal, role of RTS as a source of hidden indoor pollution. Further studies are needed to understand the relevance of this contribution in smoke-free premises in terms of risk exposure; however, waiting for about 2 min before re-entry after the last puff would be enough to avoid an unwanted additional exposure for non-smokers.

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Relation between particle mass and number for submicrometer airborne particles

Cited by 68 publications

References 14 publications

Aerosol Size Spectra and Particle Formation Events at Urban Shanghai in Eastern China

Aerosol Size Spectra and Particle Formation Events at Urban Shanghai in Eastern China

Uncertainty Budget of the SMPS–APS System in the Measurement of PM₁, PM_2.5, and PM₁₀

Residual tobacco smoke: measurement of its washout time in the lung and of its contribution to environmental tobacco smoke

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Relation between particle mass and number for submicrometer airborne particles

Cited by 68 publications

References 14 publications

Aerosol Size Spectra and Particle Formation Events at Urban Shanghai in Eastern China

Aerosol Size Spectra and Particle Formation Events at Urban Shanghai in Eastern China

Uncertainty Budget of the SMPS–APS System in the Measurement of PM1, PM2.5, and PM10

Residual tobacco smoke: measurement of its washout time in the lung and of its contribution to environmental tobacco smoke

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Uncertainty Budget of the SMPS–APS System in the Measurement of PM₁, PM_2.5, and PM₁₀