Performing Department
(N/A)
Non Technical Summary
Wild fires produce significant air pollution, posing health risks to first responders, residents in nearby areas, and downwind communities. Wildfires are increasing in size and intensity, and the fire season is growing longer. Technologies for measuring air pollutants, including particulates, carbon monoxide, nitrogen dioxide, and carbon dioxide, over the wide range of levels expected in areas downwind of wildland fires are needed.KWJ proposes to integrate printed gas sensors and particle sensor into a single, <8oz package with the dimensions <4"x5"x1" (10x12.5x2.5cm). In Phase I, we propose using a prototype 7-gas board we have developed in collaboration with Intel, and integrate with Alphasense's VOC and OPC-R1 PM sensor, which is the current state-of-the-art in miniature, optical particle detection. We plan to design a package which can be deployed in a variety of ways: worn by personnel, attached to "javelins" which can be located and relocated around the perimeter by shoving into the ground, on vehicles, and - with the rapid advancement in small UAV capabilities and range - deployed around the fire perimeter on drones. In Phase II we plan to build and test an electrostatic PM sensor, which will measure particles down to 5nm, and use far less power than the optical sensors.Very small, light-weight, unobtrusive monitoring systems will broaden the conditions under which exposure studies can be performed and will remove the need for awkward, bulky or inconvenient sampling/collection devices and batteries. This system will expand the scope of air quality monitoring and provide increased capability to produce personalized data from mobile individuals, thus improving the ability of agencies to map pollutant levels, protect human health and well being relative to environmental inhalation hazards.The ultrafine particle sensor developed during Phase II of this project will complement KWJ's new class of amperometric gas sensor, the screen-printed electrochemical sensor (SPEC), deliver high performance sensing for a wide range of applications at commodity-level prices. This new, cost-competitive, high performance electrostatic ultrafine particle technology will bridge the cost-performance gap for particulate measurement applications, just as the printed amperometric sensor has done for gaseous monitoring.
Animal Health Component
33%
Research Effort Categories
Basic
33%
Applied
33%
Developmental
34%
Goals / Objectives
In this project, we propose a sensor package, combined with ultra-low power electronics and telemetry (both BLE and cellular) which will be of tremendous benefit both toward improving the efficacy and safety of fire fighters, as well as monitoring levels of toxic gaseous pollutants emitted by the wildfire. By developing a low-power, wireless monitor, we will provide a tool that provides protection in the immediate vicinity as well as protecting and warning residences in the fire's path and surrounding area.The technical goals of this proposed project is to develop an extremely small, ultralow power, wirelessly enabled monitor including sensors for particulate, VOCs and toxic gases including carbon monoxide (CO), NO2, SO2, and ozone. In Phase II we will add an electrochemical formaldehyde sensor which is currently in early stages of development.We propose to integrate the KWJ gas sensors and electronics into a single, <8oz package of the approximate dimensions 3"x5"x1" (7.5x12.5x2.5cm). In Phase I, we propose using the prototype 7-gas board we have developed in collaboration with Intel (see Figure 4 at right), and integrate with Alphasense's VOC and OPC-R1 PM sensor, which is the current state-of-the-art in miniature, optical particle detection. During the Phase I work, we plan to make use of our current digital sensors' interfaces, as well as the digital interfaces of the commercial particle sensor, to make the system as modular as possible. This task includes bread boarding all of the required sensors and components defined in the next section, as well as gas testing, characterization, and validation of the final system. Developing the system in a modular fashion will facilitate integration of PM sensor iterations as they evolve on Tasks 3 and 4 of Phase I and further in Phase II - particle sensor development and miniaturization. Those tasks are essential to meet the size and power requirements of the personal multi-hazard monitor
Project Methods
KWJ will build a prototype device that contains multiple sensors of the highest specificity and sensitivity for the target air contaminants. The envisioned gas detection device consists of multiple KWJ/SPEC printed sensors in an array (the printed sensors are 1.0 cm x1.0 cm x 0.1cm) and we intend to use 6-8 sensors (5-7 gas sensors with a total volume ultimately of 1cm3 + VOC + PM2.5 sensor of 30cm3 in Phase I) and a PCB of about 100cm2. By the end of Phase II, we expect our entire device to be about 10x12x1cm (120cm3) and contain high performance selective sensors powered up to 1 week by an internal battery.The Phase I method for prototype development will be:Validate the individual sensors for this rugged, widely variable environmentKWJ employs a "3-Tier" sensor evaluation:Tier 1: Sensitivity (Resolution and MDL), Linearity, Response Time, repeatabilty of span and BL stabilityTier 2: Stability of response (continued exposure), cross-sensitivity/interferences, temperature effect (span and BL), Transient RH effects on span and BL; recovery from high concentrations and interferences; capacity of selective chemical filter (where applicable).Tier 3: Long-term stability under: i) ambient conditions; ii) Temperature cycling (accelerated aging); iii) <10% RH; iv) >95% RHValidate the commercial VOC and PM sensors for this environment.During Phase I, we will evaluate several optical PM sensors (current plan is to test the Alphasense OPC-R1 and newly introduced Sensirion SPS30) using a particle generator (Model 9302, TSI Incorporated) which provides a large constant dose of 5±0.3 μm poly-styrene latex spheres (PSL) (Duke 2000 Series, Thermo Fisher Scientific) to a test chamber. The density and number of spheres will be monitored using a handheld reference meter (Model 8306, Particles Plus).For VOC sensor evaluation, we plan to use ethene, to test response to the NMHC emitted in the highest concentration under variable T, P, RH as well as varying CO2 and CO convcentrations.Integrate the selected sensors into Phase I prototype monitors and test to the requirements of the specific wildland firefighting applications, e.g., stable accuracy and precision over the temperature extremes encountered outdoors. and low power requirements compatible with battery operation and reliable operation in dirty, hot, humid conditions.KWJ has 3 environtmental chambers with -70 to +100C, 0 to >95% RH, and mass flow controllers to allow introduction of samples from low ppb to ppm levels of target gases.We will measure accuracy while varying temperature, as well as in the presence of other potential interferences.From the Phase I test results and design reviews with wildfire and air monitopring experts, we will develop design of an integrated system design built around the Phase I sensor and electronics, including power requirements for low power on-board potentiostat, wireless communications, etc. to be built and field-tested in the Phase II follow-on development effort.In parallel, we will develop the electrostatic PM sensor design concept, and review with our prospective Phase II and III partners, including TSI, Alphasense, and Sensirion. A stable, high particle count electrostatic PM sensor will allow us to monitor ultrafine particulate (<200nm), as the optical sensors have a lower nominal size limit of 0.3µm.