Gordon Pierce WESTAR Spring Business Meeting Boise, ID May 27, 2014

Transcription

1 Gordon Pierce WESTAR Spring Business Meeting Boise, ID May 27, 2014

2 Traditional monitoring approach Permanent fixed sites Meets all US EPA requirements Number of sites Siting Generally neighborhood scale or greater Extensive QA/QC and reporting requirements Data used for: NAAQS designations Forecasting/public reporting Health studies Model input/validation 2

3 Desires for special studies and communities Do not always need regulatory samplers Do not always need long-term permanent sites Need to focus on different objectives Need portable monitoring equipment Cheaper Smaller Battery powered Easy for anyone to operate Easier data access Better communication with locals/citizens 3

4 Common goals between communities and regulators Identify sources Identify risks Engage the public Low cost monitoring equipment Accurate monitoring equipment Provide timely and relevant information Protect public health 4

5 Next Generations Sensors Overview Low cost = less than $2000, many less than $1000 Small, easy to transport Easy to set up at a location No line power needed No phone line needed Unobtrusive Easy to use and obtain data Common applications: Ozone Carbon monoxide Carbon dioxide Nitrogen dioxide Particulates VOC 5

6 Problems/Issues with Next- Generation Sensors Small, low-cost air monitors are becoming common and easy to obtain Anyone can monitor and post data to a website Unspecific monitoring objectives Little or no interaction with air monitoring experts More focus on design, data display, networking, mobile/web apps, etc. Quality of the data are unknown Pollutants, detection limits, interferences, accuracy, QA Sensor technology not really ready Not suitable for health risk assessment Data assimilation with traditional networks difficult Hard for agencies to deal with after data are out 6

7 Sensor concerns Often no real evaluation of sensors No field or chamber testing False positives Instrument error, interferences Indoor or personal-scale source May result in unwarranted concerns and significant resources wasted to evaluate False negatives Measuring the wrong pollutant Low sensitivity False sense of safety Spatial and temporal representativeness 7

8 What is being done? EPA has held a series of Air Sensors workshops focused on next-generation air monitoring 3 held so far Next one is June 9-10, 2014 at EPA (RTP) Goal is to get information to vendors on: What types of monitoring is needed? What are typical ambient levels of pollutants? What types of sensors are available? What validation/calibration is needed? What documentation is needed? 8

9 EPA Draft Roadmap Intended to summarize major findings from literature reviews, workshops, and discussions with experts about Next Generation of Air Monitoring (NGAM), particularly sensor technologies. Developed to share EPAs early thinking about how best to support the successful development and use of new monitoring technologies Identifies key issues in need of EPA leadership and an ambitious set of priority objectives for EPA and other partners to address 9

10 Examples CairClip AQMesh M-Pod Dylos AirCasting Air Quality Egg CitiSense 10

11 Sonoma Technology, Inc. Example Air Quality Agency Sponsor: San Joaquin Valley Unified Air Quality Management District Type: Decision Making Objective: Determine ozone gradients in and around Arvin, California Develop an algorithm to predict peak ozone concentrations in the greater Arvin area Approach: Deployed >20 low-cost ozone sensors around Arvin Collected 6 weeks of data Conducting quality control and data analysis 11

12 Sonoma Technology, Inc. About the Aeroqual S500 Sensors Gas-sensitive semiconductor. Uses heated tungstic oxide (WO 3 ); in the presence of ozone, conductance of WO 3 decreases. Changes in the conductance are calibrated to measure ozone. During the no-flow state, the high temperature of the sensor results in thermal decomposition of surrounding ozone, and the sensor measures a zero ozone conductance. During the fan on state, the sensor responds to incoming ozone, and the sensor conductance decreases. Manufacturer s Specifications Performance Characteristics Value Units Performance Characteristics Value Linear range ppm Precision ±0.005 ppm Resolution ppm Baseline drift < Units ppm/ 1000 hrs Accuracy of calibration ±0.005 ppm Operational range 0 to 40 deg C Minimum detection limit ppm Relative humidity 10 to 90 % 12

13 Sonoma Technology, Inc. The Aeroqual Sensor Sensor head after field study. The particle composition was mostly silicates with some carbonaceous 13

14 Sonoma Technology, Inc. Collocation Results The accuracy of the 1-hr measurements is about 3 ppb The precision is ±4% at the 95% confidence level. Data meet data accuracy requirements for understanding spatial gradients. Final Corrected Data Compared to FEM Bakersfield 14

15 Sonoma Technology, Inc. Summary: SJV Ozone The Aeroqual ozone sensors appear to be very useful for detecting spatial ozone gradients. Temporary and permanent monitor data allowed us to develop predictive ozone equations for key locations void of permanent monitors. Allows air districts to provide air quality information in areas void of permanent monitors. Sensor drift does occur; collocation of instruments is key. Strong spatial gradients in ozone over short distances existed in the study area, even in rural areas. Titration and local flows likely have strong impact on ozone gradients. 15

16 Sonoma Technology, Inc. Example - Local Wood Smoke Impacts Funded by the Bay Area AQMD How representative is the permanent monitor? What is spatial variability of PM 2.5? How good are lower-cost sensors? Study components 5 FEM PM 2.5 monitors Mobile monitoring within neighborhoods Data analysis 16

17 Sonoma Technology, Inc. Mobile Instrument Setup Instruments Thermo PDR-1500 (PM 2.5 ) Shinyei PPD-60PV (particle count) Temperature & humidity sensor Wind velocity sensor Velocity $4,500 Velocity $15 Temp/RH $12 Particles $120 17

18 Sonoma Technology, Inc. Instrument Setup 18

19 Sonoma Technology, Inc. Jan. 15, 10:00 PM FEM 19

20 Other WESTAR examples Oregon Interest in low cost sensors Desire to collocate with FRM/FEM analyzers to validate Washington Some local agencies are looking at using Seeing an increasing level of interest Colorado CairClip ozone sensors to be used by EPA as part of NCAR FRAPPE / NASA DISCOVER-AQ projects in July- August 2014 in North Front Range area Will collocate some with FEM analyzers 20

21 Air Sensor Guidebook for Users and Developers In development by Sonoma Technology, Inc. Draft presented to the Monitoring Steering Committee Air quality 101 Purchasing a sensor How to collect useful data using air sensors Sensor performance Maintaining your sensing device Generally favorable opinions Need section on communicating results Need more on data interpretation and tie-in to risk STI will revise for release in

22 Questions? 22