Nephelometer. integrating

Aircraft can take vertical temperature soundings and can measure air pollutant and tracer concentrations and turbulence intensity. Airborne lidar can measure plume heights, and integrating nephelometers can determine particle size distributions. 

Aerosol sampling instruments were housed in an air conditioned monitoring trailer operated by NWC. The particle light scattering coefficient, bg, was continuously measured with modified MRI Model 1561 integrating nephelometer. The nephelometer automatically zeroed daily and was calibrated quarterly. 

FIGURE 9.21 Schematic diagram of an integrating nephelometer (from Charlson et at., 1967). 

The uptake of water with increasing RH causes an increase in both mass and radius and a decrease in refractive index the net effect of all these factors is an increase in light scattering. This can be seen in Fig. 9.27, where the light scattering coefficient, bxai 6sp, for some ambient aerosol particles measured using an integrating nephelometer was found to increase with the liquid water content of the aerosols. 

Particle light-scattering coefficient Integrating nephelometer Scattering intensity from particles within a dehned light path as a function of wavelength -h... 

As noted in Section 4.04.2.3, key optical properties of aerosols are represented by the light-scattering coefficient, and light-absorption coefficient, both with reference to the particulate matter. The light-scattering coefficient of an aerosol can be measured by using nephelo-metry (Table 2). The integrating nephelometer (Anderson et al., 1996) exposes an aerosol to... 

The integrating nephelometer provides information on total aerosol light scattering. Show how the characteristics of the instrument would appear within the framework of Table 6.3. 

For high-throughput screening of solubilities, where the amount of compound may be severely restricted, reporting kinetic solubilities may be adequate. In this respect, Quarterman et al. (1998) have described a technique based on a 96-well microtitre technique with an integral nephelometer. The process of determining kinetic solubilities by this method was summarized as follows. Aliquots of the aqueous solution are placed in the microtitre wells, to which are added 1 p,L of the compounds in DMSO, and the plate is shaken. The turbidity of... 

Chapman,, 1930 On ozone and atomic oxygene in the upper atmosphere. Phil. Mag. 10,369-383. Charlson, R. J., Pueschel, R. F. and Ahlquist, N. C., 1969 Use of the integrating nephelometer for studying deliquescent aerosols. Proc. 7 Internal. Cortf. on Condensation and Ice Nuclei, Prague and Vienna, 293-303. 

Integrating nephelometer—essentially responsive to the in situ mass in the accumulation mode only 0.15 2 1% of air-scattering (about 1 pg/m ) Light-scattering ... 

FIGURE 16.14 Diagram of an integrating nephelometer. Reprinted with permission from J. Air Poll. Control Assoc., 17, 467 (1967). 

The integrating nephelometer is a photometer designed to measure the light scattered from an aerosol over as wide a range of angles as possible. The instrument shown in Fig. 16.14 measures the scattered light from 8 to 170 and can measure scattering coefficients as small as 10 /m from a sensitive volume of about 1 L. This instrument provides a measurement of due to particles and gas molecules. If is zero, the nephelometer yields a direct measurement of that provides an instru-... 

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