METHOD TO DETERMINE MAXIMAL SIZE AND CONCENTRATION OF SUBMICRON AEROSOL PARTICLES Russian patent published in 2014 - IPC G01N15/02 

FIELD: measurement equipment.

SUBSTANCE: invention refers to the measurement of aerosol particle characteristics by optical methods. The method consists in measuring the optical radiation attenuation in the visible and near infrared regions of spectrum. The maximal size and concentration of aerosol particles are determined according to the formulas: $$D_{\max }=\frac{{\lambda }_{*}}{\pi }{\alpha }_{*}\left({\lambda }_{*}\right),$$ $$C_m=\frac{\rho \cdot {10}^{-6}}{1.5\cdot l}{\overline{\tau }}_{*},$$ where D_max - maximal particle diameter, µm; C_m - particle mass concentration, kg/m³; ρ - particle material density, kg/m³; l - optical path length, m; λ∗, $${\overline{\tau }}_{*}$$ - coordinates of the point of reaching the function asymptote $$\overline{\tau }\left(\lambda \right)=\lambda \cdot \tau \left(\lambda \right)/F\left(\lambda \right),$$ mcm; τ(λ) - measured spectral optical density; α*(λ) - dependence of diffraction parameter value on the wave length α=νπD/λ, with the diffraction parameter value corresponding to the start point abscissa of the function Q(α) deviation from the function Q_p(α); Q(α) - attenuation efficiency factor calculated according to exact formulas of the Mie theory for specified dependences of refraction index n(λ) and absorbance index "ж"(λ) of aerosol particle material; $$F\left(\lambda \right)=\frac{24n\left(\lambda \right)\text{æ}\left(\lambda \right)}{{\left[{\text{n}}^{\text{2}}\left(\lambda \right)-{\text{æ}}^{\text{2}}\left(\lambda \right)+2\right]}^2+{\left[2n\left(\lambda \right)\text{æ}\left(\lambda \right)\right]}^2}$$ - attenuation efficiency factor for Rayleigh scattering.

EFFECT: higher accuracy at the determination of submicron particle characteristics.

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