Optical properties of the San Joaquin Valley aerosol collected during the 1995 integrated monitoring study

Richards, L.W.; Alcorn, Siana; McDade, Charles E.; Couture, Tiina; Lowenthal, Douglas H.; Chow, Judith C.; Watson, John G.

doi:10.1016/s1352-2310(99)00267-8

Cited by 42 publications

(33 citation statements)

References 12 publications

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“…Although the growth of particles with increasing relative humidity can depend strongly on particle material and size (McMurry and Stolzenburg, 1989 ), in some conditions the water uptake is a more simple function of relative humidity (Richards et al, 1999 ).…”

Section: Discussionmentioning

confidence: 99%

Photometrically measured continuous personal PM2.5 exposure: Levels and correlation to a gravimetric method

Lanki¹,

Alm²,

Ruuskanen

et al. 2002

J Expo Sci Environ Epidemiol

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There is evidence that hourly variations in exposure to airborne particulate matter ( PM ) may be associated with adverse health effects. Still there are only few published data on short -term levels of personal exposure to PM in community settings. The objectives of the study were to assess hourly and shorter -term variations in personal PM 2.5 exposure in Helsinki, Finland, and to compare results from portable photometers to simultaneously measured gravimetric concentrations. The effect of relative humidity on the photometric results was also evaluated. Personal PM 2.5 exposures of elderly persons were assessed for 24 h every second week, resulting in 308 successful measurements from 47 different subjects. Large changes in concentrations in minutes after cooking or changing microenvironment were seen. The median of daily 1 -h maxima was over twice the median of 24 -h averages. There was a strong significant association between the two means, which was not linear. Median ( 95th percentile ) of the photometric 24 -h concentrations was 12.1 ( 37.7 ) and of the 24 -h gravimetric concentrations 9.2 ( 21.3 ) g / m 3 . The correlation between the photometric and the gravimetric method was quite good ( R 2 = 0.86 ). Participants spent 94.1% of their time indoors or in a vehicle, where relative humidity is usually low and thus not likely to cause significant effects on photometric results. Even outdoors, the relative humidity had only modest effect on concentrations. Photometers are a promising method to explore the health effects of short -term variation in personal PM 2.5 exposure.

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Section: Discussionmentioning

confidence: 99%

Photometrically measured continuous personal PM2.5 exposure: Levels and correlation to a gravimetric method

Lanki¹,

Alm²,

Ruuskanen

et al. 2002

J Expo Sci Environ Epidemiol

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“…Published research results (reviewed below) based on nephelometric measurements in rural field settings are inconsistent with regard to data quality (i.e., nominal (factory-calibrated) readings vs data scaled to fit gravitational field samples, particle size fraction of gravimetric calibration) and treatment of temporal resolution (Brauer, 1995(Brauer, , 1996Ezzati et al, 2000a, b;Balakrishnan et al, 2004). Several studies have observed humidity-dependence of light scattering signals in ambient environments (e.g., Thomas and Gebhart, 1994;Richards et al, 1999;Day et al, 2000;Day and Malm, 2001). However, previously published field research using nephelometers in solid fuel-using rural households does not explicitly contend with high relative humidity excursions.…”

Section: Scope Of This Papermentioning

confidence: 99%

“…In low-pollution field environments in which particles were not chemically and physically well-characterized, two investigations with the pDR report successful statistically based correction for relative humidity effects on the relationship between nephelometric signal and gravimetric analysis (Richards et al, 1999;Wu et al, 2005b). Above 95% relative humidity, the upper limit of manufacturer's specifications for pDR operation, the scattering signal's dependence on relative humidity is too sensitive to enable empirical correction, given the precision and accuracy limitations of portable relative humidity data-logging devices (Richards et al, 1999).…”

Section: Scope Of This Papermentioning

confidence: 99%

“…Above 95% relative humidity, the upper limit of manufacturer's specifications for pDR operation, the scattering signal's dependence on relative humidity is too sensitive to enable empirical correction, given the precision and accuracy limitations of portable relative humidity data-logging devices (Richards et al, 1999).…”

Section: Scope Of This Papermentioning

confidence: 99%

“…However, most previously published environmental investigations of nephelometer performance relative to gravitational determinations depict controlled laboratory settings or relatively low (1-60 mg/m 3 ) particle concentrations (Richards et al, 1999;Howard-Reed et al, 2000;Quintana et al, 2000;Sioutas et al, 2000;Lanki et al, 2002;Liu et al, 2002;Wallace et al, 2003Wallace et al, , 2006Allen et al, 2004;Chakrabarti et al, 2004;Jenkins et al, 2004;Wu et al, 2005b). Our research explores the performance of a commercially available portable nephelometer, the MIE personal DataRAM (pDR-1000, Thermo Electron, Franklin, MA, USA), in a highly polluted field context.…”

Section: Introductionmentioning

confidence: 99%

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Field performance of a nephelometer in rural kitchens: effects of high humidity excursions and correlations to gravimetric analyses

Fischer¹,

Koshland²

2006

J Expo Sci Environ Epidemiol

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Rural kitchens of solid-fuel burning households constitute the microenvironment responsible for the majority of human exposures to health-damaging air pollutants, particularly respirable particles and carbon monoxide. Portable nephelometers facilitate cheaper, more precise, time-resolved characterization of particles in rural homes than are attainable by gravitational methods alone. However, field performance of nephelometers must contend with aerosols that are highly variable in terms of chemical content, size, and relative humidity. Previous field validations of nephelometer performance in residential settings explore relatively low particle concentrations, with the vast majority of 24-h average gravitational PM 2.5 concentrations falling below 40 mg/m 3 . We investigate relationships between 24-h gravitational particle measurements and nephelometric data logged by the personal DataRAM (pDR) in highly polluted rural Chinese kitchens, where gravitationally determined 24-h average respirable particle concentrations were as high as 700 mg/m 3 . We find that where relative humidity remained below 95%, nephelometric response was strongly linear despite complex mixtures of aerosols and variable ambient conditions. Where 95% relative humidity was exceeded for even a brief duration, nephelometrically determined 24-h mean particle concentrations were nonsystematically distorted relative to gravitational data, and neither concurrent relative humidity measurements nor use of robust statistical measures of central tendency offered means of correction. This nonsystematic distortion is particularly problematic for rural exposure assessment studies, which emphasize upper quantiles of time-resolved particle measurements within 24-h samples. Precise, accurate interpretation of nephelometrically resolved short-term particle concentrations requires calibration based on short-term gravitational sampling.

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Monitoring of 1-Min Personal Particulate Matter Exposures in Relation to Voice-Recorded Time–Activity Data

Quintana

Valenzia

Delfino

et al. 2001

Environmental Research

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Optical properties of the San Joaquin Valley aerosol collected during the 1995 integrated monitoring study

Cited by 42 publications

References 12 publications

Photometrically measured continuous personal PM2.5 exposure: Levels and correlation to a gravimetric method

Photometrically measured continuous personal PM2.5 exposure: Levels and correlation to a gravimetric method

Field performance of a nephelometer in rural kitchens: effects of high humidity excursions and correlations to gravimetric analyses

Monitoring of 1-Min Personal Particulate Matter Exposures in Relation to Voice-Recorded Time–Activity Data

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