Grantee Research Project Results

Final Report: Size-Selection Aerosol Characterization Instrument

EPA Contract Number: EPD12007
Title: Size-Selection Aerosol Characterization Instrument
Investigators: Timko, Michael
Small Business: Aerodyne Research Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2012 through August 31, 2012
Project Amount: $79,991
RFA: Small Business Innovation Research (SBIR) - Phase I (2012) RFA Text | Recipients Lists
Research Category: SBIR - Air and Climate

Description:

In this SBIR project, Aerodyne Research Inc. (ARI) has developed technologies to improve its existing Aerosol Chemical Speciation Monitor (ACSM) so that it can provide size-resolved aerosol particle composition data for particles. Ambient aerosol particles play a significant role in adversely affecting human health, in altering the chemistry and the radiative balance of the Earth's atmosphere, and in reducing visibility. Recent studies have linked urban particulate pollution to high mortality and morbidity levels, respiratory-related health problems, and increased risk of heart failures in susceptible individuals. The effects of aerosols represent the single largest source of uncertainty in our understanding of global radiative forcing. Because these effects cover many time and length scales, understanding the health and climate effects of ambient particles requires time-resolved measurements of concentrations and compositions over long time periods and in many locations. Moreover, the persistence and distributions of aerosol particles and their potential for health, environmental and climate impacts depend on both particle size and composition. Making size-resolved aerosol composition measurements with the required time resolution and over the length and time scales needed for local and global effects modeling has been impossible due to the lack of automated particle composition monitors. ARI's existing product, the ACSM, provides real-time measurements of particle composition. Moreover, the ACSM is compact, cost effective and can be operated remotely. However, the ACSM lacks size resolution capabilities, and due to its detection scheme, provides limited information on particles > 1 µm.

The purpose of this SBIR project was to combine simulation and experimental methods to develop a technology to: 1) provide particle size resolution capabilities to the ACSM, and 2) add a light scattering module to the ACSM so that it can measure the mass of particles > 1 µm. For particle size resolution, ARI evaluated two separate approaches: particle dispersion and multiplexed chopping. Particle dispersion is a modification of ARI's existing aerodynamic lens that has shown promise for segregating aerosol particles based on their size. Multiplexed chopping is a new method of measuring particle velocities; since particle velocities depend on their size, measuring their velocity is a convenient means of achieving size resolution.

Summary/Accomplishments (Outputs/Outcomes):

Simulation and experimental activities confirmed that particle dispersion is controlled by imperfections in the aerodynamic lens used as an inlet to ARI's mass spectrometer chamber. Moreover, ARI performed simulations to understand more completely the aerodynamic lens so that it can focus the entire particle size range of interest to the EPA (< 10 µm). Specifically, ARI identified individual components within the lens that will allow ARI to expand the dynamic range and shift the lens transmission to larger particles. Experimental work with multiple lenses verified that ARI can achieve particle dispersion using its aerodynamic lens, though controlling it will be difficult. Multiplexed chopping showed promise as a robust new method for obtaining particle size distribution data, with greater than a 10-fold improvement in signal/noise relative to ARI's current methods.

Conclusions:

ARI has shown that: 1) its improved understanding of aerosol particle focusing can result in a sampling method appropriate for a wide range of particles (< 5 µm has been proven in the laboratory); 2) multiplexed chopping can be used to improve signal-to-noise by a factor of about 10 relative to ARI's current methods; and 3) light scattering methods can be implemented for particles larger than 1 µm. These three advances will enable a next-generation ACSM that packages all of the existing instrument strengths (e.g., cost, size, usability) with size resolution capabilities and improved sensitivity.

Commercialization.

Foresight Science & Technology, an independent firm, performed a market niche analysis for the SBIR instrument. Crucially and after an exhaustive search, Foresight Science & Technology concluded that no product on the market duplicated the capabilities that ARI has been demonstrating for the SBIR instrument. ARI has identified two markets: outdoor air quality measurement and engineered nanoparticle health effects monitoring. ARI has a long track record of delivering new instruments for performing outdoor air quality measurements, having sold more than 100 aerosol mass spectrometers at a total value of more than $40M. The SBIR instrument duplicates much of the functionality of the aerosol mass spectrometer, but at a fraction of the cost. Therefore, ARI anticipates that the SBIR instrument will have a much broader market in air quality monitoring applications. Specifically, the U.S. EPA runs several different types of air quality monitoring stations that will benefit from the SBIR instrument: 1) NCORE, 63 urban sites, 17 rural sites; 2) IMPROVE, 177 total sites; and 3) PM2.5 Network, 1,050 total sites. Taking as ARI's basis the combined NCORE and IMPROVE sites (257 in total) and an instrument priced at $100K, ARI arrives at a total sales figure of approximately $25M. Outfitting the entire PM2.5 Network would increase total sales to more than $100M. The engineered nanoparticle market is currently a smaller market for ARI's instrument than atmospheric monitoring, but it has much greater growth potential. Foresight Science & Technology estimates that the engineered nanoparticle monitoring market is approximately $9M; however, Foresight asserts that the market may be 2 to 4 times larger than this. Moreover, the market for engineered nanoparticle monitoring will grow due to continuing commercial and government interest in developing user products enabled by nanoscale components and mounting concerns about the environmental and health impacts of engineering nanoparticles

Supplemental Keywords:

air pollution, particle monitoring, aerosol particles, aerodynamic lens, light scatter, particle dispersion lens, mass spectrometer

SBIR Phase II:

Size-Selecting Aerosol Characterization Instrument

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