Claudio Mazzoleni

On-road measurement of automotive particle emissions by ultraviolet Lidar and transmissometer: theory

An on-road vehicle emissions remote sensing system (VERSS) utilizing an ultraviolet laser (operating at a wavelength of 266 nm) has been developed to quantify the particulate mass in vehicle exhaust. The system simultaneously measures the backscatter and the transmission of the laser light. Obtaining the particulate matter mass concentration from the measurements depends upon a prior laboratory calibration as well as knowledge of the physical, chemical and optical characteristics of the exhaust particles.

The In-Plume Emission Test Stand: An Instrument Platform for the Real-Time Characterization of Fuel-Based Combustion Emissions

Abstract The In-Plume Emission Test Stand (IPETS) characterizes gaseous and particulate matter (PM) emissions from combustion sources in real time. Carbon dioxide (CO2), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and other gases are quantified with a closed-path Fourier transform infrared spectrometer (FTIR). Particle concentrations, chemical composition, and other particle properties are characterized with an electrical low-pressure impactor (ELPI), a light-scattering particle detector, an optical particle counter, and filter samples amenable to different laboratory analysis. IPETS measurements of fuel-based emission factors for a diesel generator are compared with those from a Mobile Emissions Laboratory (MEL). IPETS emission factors ranged from 0.3 to 11.8, 0.2 to 3.7, and 22.2 to 32.8 g/kg fuel for CO, NO2, and NO, respectively. IPETS PM emission factors ranged from 0.4 to 1.4, 0.3 to 1.8, 0.3 to 2.2, and 1 to 3.4 g/kg fuel for filter, photoacoustic, nephelometer, and impactor measurements, respectively. Observed linear regression statistics for IPETS versus MEL concentrations were as follows: CO slope = 1.1, r2 = 0.99; NO slope = 1.1, r2 = 0.92; and NO2 slope = 0.8, r2 = 0.96. IPETS versus MEL PM regression statistics were: filter slope = 1.3, r2 = 0.80; ELPI slope = 1.7, r2 = 0.87; light-scattering slope = 2.7, r2 = 0.92; and photoacoustic slope = 2.1, r2 = 0.91. Lower temperatures in the dilution air (~25 °C for IPETS vs. ~50 °C for MEL) may result in greater condensation of semi-volatile compounds on existing particles, thereby explaining the 30% difference for filters. The other PM measurement devices are highly correlated with the filter, but their factory-default PM calibration factors do not represent the size and optical properties of diesel exhaust. They must be normalized to a simultaneous filter measurement.

Monitoring Automotive Particulate Matter Emissions with LiDAR: A Review

Automotive particulate matter (PM) causes deleterious effects on health and visibility. Physical and chemical properties of PM also influence climate change. Roadside remote sensing of automotive emissions is a valuable option for assessing the contribution of individual vehicles to the total PM burden. LiDAR represents a unique approach that allows measuring PM emissions from in-use vehicles with high sensitivity. This publication reviews vehicle emission remote sensing measurements using ultraviolet LiDAR and transmissometer systems. The paper discusses the measurement theory and documents examples of how these techniques provide a unique perspective for exhaust emissions of individual and groups of vehicles.

Detection of Gasoline Vehicles with Gross PM Emissions

Light duty gasoline vehicles (LDGV) are estimated to contribute 40% of the total on-road mobile source tailpipe emissions of particulate matter (PM) in California. While considerable efforts have been made to reduce toxic diesel PM emissions going into the future, less emphasis has been placed on PM from LDGVs. The goals of this work were to characterize a small fleet of visibly smoking and high PM emitting LDGVs, to explore the potential PM-reduction benefits of Smog Check and of repairs, and to examine remote sensing devices (RSD) as a potential method for identifying high PM emitters in the in-use fleet. For this study, we recruited a fleet of eight vehicles covering a spectrum of PM emission levels. PM and criteria pollutant emissions were quantified on a dynamometer and CVS dilution tunnel system over the Unified Cycle using standard methods and real time PM instruments. The vehicles were then tested using RSD equipment over a test track, tested with a standard Smog Check, and tested with a screening device during the Smog Check. The PM emission rates of the visibly smoking vehicles range from 60 to 1718 mg/mi over the UC cycle. The light or invisible smokers had PM emissions ranging from 7 to 25 mg/mi. The smoking vehicles showed particle number rates on the order of 10

The iron lung: a device for the continuous delivery of fine particulate matter.

In aerosol research, bag-sampling techniques are commonly used for temporary storage of aerosols. They have been used for aging studies and to integrate over fluctuations in aerosol properties and concentrations. Here, we describe the design and operation of an iron lung aerosol sampler consisting of a large volume (∼277 l) drum and a conductive drum liner. This iron lung is used for the continuous delivery of fine particulate matter. Its performance for storage and sampling of fine particulate matter has been evaluated with soot from a kerosene lamp by characterizing the change of particle number and size distribution as function of time with a scanning mobility particle sizer. Changes in these properties have been shown to be smooth, demonstrating the utility of the iron lung described here.