A compact, low-cost, network accessible, optical particle counter for the real time measurement of submicron aerosol particle size distributions

EPA Grant Number: R835139
Title: A compact, low-cost, network accessible, optical particle counter for the real time measurement of submicron aerosol particle size distributions
Investigators: Bertram, Timothy H
Institution: University of California - San Diego
EPA Project Officer: Chung, Serena
Project Period: February 1, 2012 through January 31, 2015
Project Amount: $250,000
RFA: Developing the Next Generation of Air Quality Measurement Technology (2011) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air


Atmospheric aerosol particles play a critical role in Earth’s radiation budget, act to limit visibility through the scattering and absorption of radiation, and represent a significant respiratory health hazard in urban environments. However, the existing network of aerosol particle measurements is significantly sparse, and unable to capture the strong heterogeneity in particles that exists in urban locations. In addition, current 24-hour air quality standards of particulate matter are based solely on the total mass of particles with diameters less than 2.5 μm, and do not account for variations in particle size or total number. As a result, air quality assessments and local and regional modeling efforts are: 1) limited by a paucity of data, and 2) unconstrained by routine observations of particle number and size, which are both critical metrics for assessing the impact of aerosol particles on visibility and human health.


The objective of this proposal is the development of a miniature, wireless optical particle counter (OPC) capable of measuring and transmitting submicron aerosol particle number and size distributions to a remote server in real-time. The proposal aims to provide the framework for significant improvements in the spatial and temporal resolution of continuous aerosol particle measurements on the city scale, while dramatically improving the availability of these data in real time.


We propose the development of a miniature OPC that incorporates a high power blue diode laser into the optical cavity of an existing commercial handheld OPC to measure submicron aerosol particle number and size distributions. The OPC will be controlled by a custom Arduino microprocessor capable of transmitting data to a remote server via a wireless connection. Data received by the remote server will be made accessible in real-time through an interactive website. We propose the construction of five identical sensors that will be deployed to both stationary and mobile platforms throughout San Diego County.

Expected Results:

We expect that the development of the miniature, wireless OPC and the measurements proposed here will provide a foundation for the future construction of a wide sensor network that will vastly improving the spatial and temporal data coverage of particle number on a regional scale. Beyond the development of the sensor, the specific results from this project will include: 1) an initial assessment of the scales of variability in particle number and size in San Diego County, which is critical for the establishment of a future high density network of air quality sensors, 2) the direct comparison of particle number and size with the current air quality standard for particulate matter, PM2.5, and 3) evaluation of the OPC performance under a wide array of sampling conditions to determine necessary standard operating procedures for continuous measurements.

Publications and Presentations:

Publications have been submitted on this project: View all 1 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 1 journal articles for this project

Supplemental Keywords:

ambient air, mobile sources, exposure, health effects, environmental chemistry, engineering, monitoring, analytical

Progress and Final Reports:

  • 2012 Progress Report
  • 2013 Progress Report
  • Final Report