Low Cost PM2.5 Sensor Evaluation in Denver, CO

摘要

The Denver Dept. of Public Health and Environment (DDPHE) has deployed and evaluated numerous low cost sensors that measure PM2.5, temperature, and relative humidity since early 2018. We have sensors collocated in triplicate at Interstate 25 Globeville (I256LO; a USEPA near road site in an environmental justice area), one at La Casa (a USEPA NCore site), and one at National Jewish Hospital (a PM2.5 FEM site). Low cost sensors are garnering significant interest from regulatory agencies, researchers, and community groups as a way to measure relative differences in space and time, especially for unique events like wildfires and other source specific hot spots. Denver is focusing on PM2.5 to start based on good comparisons to FRM and FEM instruments in other real world field studies. The USEPA sites at GLO and LaCasa use GRIMM 180 EDM instruments to measure PMZ.5, while at National Jewish Hospital a Teledyne 640 is utilized. We will present results showing sensor to sensor variability, comparison with two federal equivalent method (FEM) instruments,, and comparing sensors to FEM instruments with different aerosol characteristics, i.e. near road vs residential. We will show overall bias of the sensors against the FEM instruments, seasonal variation based on temperature and humidity changes, and how we are reporting data to the community, both corrected and uncorrected. Denver will also discuss our expanding sensor network over the next several years as a result of a $1M Bloomberg Mayor's Challenge grant and how we are partnering with the local school district to make this exposure information actionable for the 10%+ of Denver Public School students affected by asthma. We also have plans to strategically deploy at least 100 more sensors throughout the city via an innovative public private partnership (P3), that will add nitrogen dioxide and/or ozone to the monitoring suite.