A new approach for determining optimal placement of PM_2.5air quality sensors: case study for the contiguous United States

Abstract

Considerable financial resources are allocated for measuring ambient air pollution in the United States, yet the locations for these monitoring sites may not be optimized to capture the full extent of current pollution variability. Prior research on best sensor placement for monitoring fine particulate matter (PM2.5) pollution is scarce: most studies do not span areas larger than a medium-sized city or examine timescales longer than one week. Here we present a pilot study using multiresolution modal decomposition (mrDMD) to identify the optimal placement of PM2.5 sensors from 2000-2016 over the contiguous United States. This novel approach incorporates the variation of PM2.5 on timescales ranging from one day to over a decade to capture air pollution variability. We find that the mrDMD algorithm identifies more high-priority sensor locations in the western United States than those expected along the eastern coast, where a large number of EPA PM2.5 monitors currently reside. Specifically, 53% of mrDMD optimized sensor locations are west of the 100th meridian, compared to only 32% in the current EPA network. The mrDMD sensor locations can capture PM2.5 from wildfires and high pollution events, with particularly high skill in the West. These results suggest significant gaps in the current EPA monitoring network in the San Joaquin Valley in California, northern California, and in the Pacific Northwest (Idaho, and Eastern Washington and Oregon). Our framework diagnoses where to place air quality sensors so that they can best monitor smoke from wildfires. Our framework may also be applied to urban areas for equitable placement of PM2.5 monitors.

Evaluation of Model-Based PM2.5 Estimates for Exposure Assessment during Wildfire Smoke Episodes in the Western U.S.

“…Our conclusion that more western wildfire-specific monitoring is needed to capture population exposure to wildfire smoke is in agreement with the findings of two studies published in 2022, which used very different methodologies�one used mode decomposition on the Di estimates 45 and the other used chemical transport modeling under past and future climate conditions. 46 Both of these studies focused on the network of EPA monitors (and our study additionally used the USFS mobile smoke monitors), but another possibility for future years is including data from low-cost air quality sensors, which are much less accurate than EPA monitors and the mobile smoke monitors, but can provide more high-resolution spatial and temporal information on PM 2.5 .…”

Investigating Use of Low-Cost Sensors to Increase Accuracy and Equity of Real-Time Air Quality Information

“…This might be addressed by considering more spatial and temporal correlations in the LCS measurement errors. In terms of LCS placement, while we chose relatively simple selection strategies to facilitate comprehension and comparison, future research could harness more sophisticated statistical and/or atmospheric modeling techniques ,, to identify locations yielding key spatiotemporal information or to prioritize some LCS placements near EPA monitors for the purposes of sensor calibration. Finally, there is more work to be done investigating how access to real-time AQ information and/or alerts translates into public health and economic benefits, as several studies have begun exploring. − …”

Prescribed burns as a tool to mitigate future wildfire smoke exposure: Lessons for states and rural environmental justice communities

“…Such progress in spatial resolution has led to an increased focus on urban centers at the expense of rural, at-risk communities (Pellow, 2016). For example, outside of metropolitan hubs, the Central Valley in California and Central/Eastern Washington State have large populations of non-white Hispanic agricultural workers who are disproportionately affected by smoke PM2.5 as an occupational hazard (Cedar River Group, 2012;Chandrasekaran, 2021;Garcia 2007;Marlier et al, 2022), but whose PM2.5 exposure is not well monitored (deSouza and Kinney, 2021; Kelp et al, 2022). The Navajo nation, a Native American reservation in the Southwest, is the largest land area held by an indigenous tribe in the United States (Guiterman et al, 2019).…”