Kimberly Hornberger, a presenter from Raleigh, described a PurpleAir sensor project deployed across Buncombe County to provide additional, non-regulatory air monitoring after Hurricane Helene. The county borrowed PurpleAir sensors through an EPA sensor loan program and began deploying them late last year to add coverage between regulatory monitors, particularly where smoke from wildfires produced short, sharp PM2.5 spikes.

Hornberger said the network’s daily-average data (January–October) tracked closely across colocated sensors but showed short-lived spikes tied to a March wildfire in nearby South Carolina and later to Canadian wildfires. “We found this EPA sensor loan program that we could borrow in terms of the PurpleAir sensors from,” she said, and noted the sensors are non-regulatory tools meant to improve situational awareness, not replace regulatory monitors.

She explained technical limitations and quality-assurance steps: the PurpleAir units report two channels and staff check that the channels align; they are less rigidly QA’d than regulatory monitors, so staff examine channel agreement and create monthly charts to spot anomalies. Hornberger described deployment challenges — finding power and reliable Wi‑Fi, swapping units when devices failed, and the difficulty of deploying from Raleigh to Asheville — and said the EPA advised placing some units at libraries and fire departments once the loan ended.

Board members asked whether the network covered all of Western North Carolina; Hornberger said most sensors are concentrated in Buncombe County with one sensor in a neighboring county and described plans to seek additional DAQ sensors for broader coverage. Ashley, the director, said the county has applied for additional PurpleAir units in a multi-jurisdiction Helene recovery application that would place sensors at 21 fire departments if awarded, and that the county is renewing the current EPA loan while awaiting a decision.

The county emphasized the intended use of PurpleAir data: spot coverage of smoke and local events, not regulatory compliance. Hornberger and staff recommended co-locating units with public-facing institutions to improve public access to real-time data. The board’s questions focused on calibration practices, the limits of the sensors, and how the project would scale if the Helene recovery grant yields additional units.

The board did not take formal action on the presentation. The county will continue the pilot while pursuing additional funding and formalizing placements at libraries and fire departments if grants or supplemental sensor loans are awarded.