A novel approach to the development of 1-hour threshold concentrations for exposure to particulate matter during the response to episodic air pollution events

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Episodic air pollution events, eg wildfires, result in significant increases in pollutant concentrations over a short duration. These events are an increasing phenomenon because of climate warming. Moreover, despite evidence showing that inflammatory response in humans to particulate (PM) exposure occurs in only a few hours, the averaging period for PM exposure guideline values is 24-h. Thus, short-duration (1-h averaging period) exposure guidelines are needed to inform population exposure advice.

Two approaches were used to generate 1-h guideline values for PM exposure: (1) data from UK major air pollution incident monitoring was used to determine a probabilistic relationship between 1-h PM10 or PM2.5 measurements and exceedance data for a range of 24-h guideline values (GVs); (2) we applied Receiving Operating Characteristic statistical analysis to an extensive US PM monitoring data set (38 million hours of data), allowing the determination of 1-h threshold concentrations that predict exceedances of US EPA air quality guideline (AQI) category boundaries.

We found that the maximum-observed 1-h PM concentration in any rolling 24-h averaging period is an excellent predictor of exceedances of 24-h guideline values. This has allowed us to develop de-facto 1-h GVs that correspond to a range of air quality guidance. E.g. we propose a 1-hr PM10 GV of 550μgm-3 for evacuation of exposed areas. Our 1-h GV for evacuation is similar to the (withdrawn) 1–3-h average ‘Recommended Action Level’ for closing public buildings, which was set of 526μgm-3 for PM10/PM2.5 during wildfires.

This straightforward approach allows for the development of 1-hr GVs that can be used to make much more timely public health protection decisions during the response phase to an episodic air pollution incident.
Original languageEnglish
Publication statusAccepted/In press - 18 Jun 2024
Event17th European Public Health Conference: Sailing the Waves of European Public Health: Exploring a Sea of Innovation - Lisbon, Portugal
Duration: 13 Nov 202415 Nov 2024


Conference17th European Public Health Conference
Internet address

Research Group keywords

  • Environmental Monitoring and Reconstruction

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