Analysis of monitoring data from major air pollution incidents: translational lessons for public health and community resilience policy and practice

Abstract

Episodic air pollution incidents tend to be acute in nature and demand a rapid public health risk assessment to understand their likely impact on exposed populations. Incidents can result from wildfires, dust storms, and industrial open uncontrolled fires that have increased in frequency in recent years. The exposure of a human population is a hazard to public health, and public health emergency preparedness (PHEP) should be involved in reducing their impact on health. Despite the threat to health, there is a paucity of knowledge surrounding these incidents because of their sporadic nature, which makes it difficult to predict when and where they will occur. Thus, it is unlikely that air pollutant plume monitoring will be available. There remains a need to improve our understanding of the nature, composition, and potential health impacts of emissions from major incident fires.

Since April 2009, across England, Scotland, and Wales, the public health response to major air pollution incidents has been coordinated by a multi-agency ‘Air Quality Cell’ (AQC). Therefore, AQC records provide an opportunity to improve our understanding of these incidents. This thesis has generated the first ever collation of AQC records which formed the basis for completing a systematic exploratory data analysis using an interplay of exploratory methodologies, including statistical analyses, visualisations, custom model development, plume modelling, and spatial analyses. Exploratory findings were aligned with an adapted implementation of the source – pathway – receptor conceptual model (SPR) to construct the relationship between the cause of the incidents, propagation of the plume, and extent and vulnerability of the exposed population. The SPR was interwoven with (1) a public health intervention model and (2) the integrated emergency management model (IEM) to develop a representation of PHEP. The SPR relationship has been translated into evidence-based recommendations for practitioners that inform policy and practice for public health protection not only during response to incidents but also to prevent them from occurring.

Directed by the AQC records, the focus of this research was industrial open uncontrolled fires as the dominant cause of major air pollution incidents. Multiple instances of organic and inorganic species monitoring, such as NO2, COCl2, and C2H3NO, exceeded the Acute Exposure Guideline Level (AEGL) and Emergency Response Planning Guidelines (ERPG) standards. Most were at (discomfort) although some prolonged exposures reached Level-2 (long-lasting effects) or Level-3 (potentially life-threatening). In addition, populations were exposed to incident-averaged concentrations ranging from 38 to 1,450 μg m−3 for PM10 and 7 to 258 μg m−3 for PM2.5. However, several incidents had 15-minute averaged short duration concentrations of 6,527 μg m−3 for PM10 and 652 μg m−3 for PM2.5, respectively. This represents the ceiling of the Osiris instrument. For 23-hours of validated PM10 monitoring, back trajectory modelling at one typical AQC event showed a mass concentration of >1,000 μg m-3 with maximum hourly concentrations of 3,000 – 5,400 μg m-3. Despite these significant concentrations, there are no equivalent short-duration exposure guidelines for PM10 or PM2.5. Probability models were developed from AQC records of 1-hr PM10 or PM2.5 concentration monitoring to predict the probability of an established 24-hr guideline being reached. Practitioners now have the ability to make informed decisions when advising the public.

For the first time for a major fire incident, spatial analysis of a time-integrated modelled plume was carried out, which indicated that between 7,856 and 18,305 residents were exposed to the US EPA Air Quality Index categories of ‘hazardous’ and ‘above the AQI’ over the 23-hour duration for which monitoring was available. Furthermore, a developed vulnerability profile suggested that this population could have been more susceptible to the impact of the plume: socioeconomic indicators (employment, educational attainment) and the extent of pre-existing health conditions were all worse than the English median. Major air pollution incident characteristics have been translated to suggested policy development recommendations to reduce the reported threat to populations and their health. These sites were regulated under an Environmental Permit, suggesting that regulators could use their regulatory power to promote fire precautions. The use of environmental regulatory law is by extension a contribution to PHEP prevention. Moreover, broader policy questions about how a circular waste economy can be employed to avoid these incidents and how spatial planning is important to identify where the sites should be safely located require further analysis.

Date of Award	23 May 2024
Original language	English
Awarding Institution	Northumbria University
Supervisor	Michael Deary (Supervisor), Helen King (Supervisor) & Frank Kelly (Supervisor)