We graphically display such chemical variations using a ternary diagram to emphasise how "air quality" in the city involves a consideration of both physical and chemical parameters, and is not simply a question of measuring particle number or mass.
Because TRPS counts each particle individually and simultaneously collects information on its size, and (to some extent) particle shape, TRPS is capable of measuring particle number concentration in dispersions (in particles/mL).
Calculated and measured particle number densities agree well during early soot growth.
In addition, agreement is demonstrated between the predicted and measured particle number distributions as a function of flow rate and axial position.
In this study, a fast response differential mobility spectrometer (Cambustion Instruments DMS500), originally designed to measure particle number distributions (PNDs) and concentrations in engine exhaust emissions, was deployed to measure particles in the 5 1000 nm size range at a sampling frequency of 10 Hz.
The TDMPS measured particle number concentrations in 26 size bins (ranges) within a range of 13.0 to 764.7 nm at a 10 min interval.
We used a portable condensation particle counter (CPC; model 3007, TSI Inc., Shoreview, MN) to measure particle number concentration inside the vehicle's cabin, while it was driven through traffic.
We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), PM10, and soot between June 2007 and June 2008 on 47 weekdays, from 0800 to 1000 hours, in diesel and electric buses, gasoline- and diesel-fueled cars, and along two bicycle routes with different traffic intensities in Arnhem, the Netherlands.
Fanning et al. 2007 measured particle numbers concentrations in the 10 100 nm range and found significant increases above background at 1.9, 2.7, and 3.3 km downwind of the Los Angeles International Airport (LAX) blast fence.
Although the particles in diesel exhaust do not have a constant density and are not always spherical, both spherical shape and constant density are typically assumed when estimating mass using sample data from instruments designed to measure particle number-weighted size distribution via particle mobility [ 22].
Our results show that currently available technologies, while allowing comparisons between samples of a given protein at a fixed concentration, may be unable to measure particle numbers accurately in a variety of protein formulations, e.g., at high concentration in sugar-based formulations.
