Oxfordshire Bonfire Night 2023
Impact of fireworks and bonfires on PM concentrations
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1 Introduction
1.1 Purpose
Every year on the 5th of November, Britons celebrate Guy Fawkes Night, or “Bonfire Night”, by lighting bonfires and setting off fireworks. While these activities are entertaining ways to spend a winter evening, they are known to emit both gaseous pollutants (NOx) and particulate matter (PM10, PM2.5). The composition of these particulates includes the toxic metals used to give fireworks their colour, the inhalation of which have harmful impacts on human health.
In 2023, Bonfire Night fell on a Sunday. The UK had only recently experienced the effects of Storm Ciarán, which brought yellow weather mornings to much of the South of England. Many regions across the UK experienced wet and stormy weather, leading to firework displays being postponed or cancelled. In other instances, atmospheric conditions prohibited smoke from dissipating, blocking sight of the displays.
This report closely examines particulate matter (PM) concentrations at the Oxford St Ebbes and Oxford High Street monitoring stations to assess how Oxfordshire was impacted by Bonfire Night activities.
1.2 Data
In 2023, Oxfordshire’s air quality network contained 7 AURN/Air Quality England sites. Figure 1 shows a map of these sites. Links to each of their respective OxonAir site information pages are included in each marker popup. Oxford St Ebbes and Oxford High Street, the only two sites which measure particulates, are highlighted in orange. In addition, known firework displays (taken from https://www.dailyinfo.co.uk/fireworks) are shown using black firework icons.
2 Daily Air Quality Index (DAQI)
2.1 What is the DAQI?
The Daily Air Quality Index (DAQI) tells you about levels of air pollution and provides recommended actions and health advice. The index is numbered 1-10, low (1) to very high (10), and divided into four bands to provide detail about air pollution levels in a simple way, similar to the sun index or pollen index (“Daily Air Quality Index (DAQI)” 2023).
“Daily Air Quality Index (DAQI).” 2023. Oxfordshire County Council. https://www.oxonair.uk/about-air-quality/daily-air-quality-index-daqi.
| Band | DAQI | O3 | NO2 | PM2.5 | PM10 |
|---|---|---|---|---|---|
| Low | 1 | 0 – 33 |
0 – 67 |
0 – 11 |
0 – 16 |
| 2 | 34 – 66 |
68 – 134 |
12 – 23 |
17 – 33 | |
| 3 | 67 – 100 |
135 – 200 |
24 – 35 |
34 – 50 | |
| Moderate | 4 | 101 – 120 |
201 – 267 |
36 – 41 |
51 – 58 |
| 5 | 121 – 140 |
268 – 334 |
42 – 47 |
59 – 66 | |
| 6 | 141 – 160 |
335 – 400 |
48 – 53 |
67 – 75 | |
| High | 7 | 161 – 187 |
401 – 467 |
54 – 58 |
76 – 83 |
| 8 | 188 – 213 |
468 – 534 |
59 – 64 |
84 – 91 | |
| 9 | 214 – 240 |
535 – 600 |
65 – 70 |
92 – 100 | |
| Very High | 10 | 241+ |
601+ |
71+ |
101+ |
| AP Band | Accompanying Health Messages | |
|---|---|---|
| at-risk individuals | the general population | |
| Low (1-3) | Enjoy your usual outdoor activities. | Enjoy your usual outdoor activities. |
| Moderate (4-6) | Adults and children with lung problems, and adults with heart problems, who experience symptoms, should consider reducing strenuous physical activity, particularly outdoors. | Enjoy your usual outdoor activities. |
| High (7-9) | Adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly if they experience symptoms. People with asthma may find they need to use their reliever inhaler more often. Older people should also reduce physical exertion. | Anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors. |
| Very High (10) | Adults and children with lung problems, adults with heart problems, and older people, should avoid strenuous physical activity. People with asthma may find they need to use their reliever inhaler more often. | Reduce physical exertion, particularly outdoors, especially if you experience symptoms such as cough or sore throat. |
2.2 DAQI in Oxford
Figure 2 and Figure 3 show the evolution of the particulate matter DAQI across November 2023 at the two Oxfordshire measurement sites. There is no clear peak in daily PM concentrations for either site or particle size. In fact, daily average particulates are higher towards the end of November. Regardless, the DAQI for PM remains in the “low” bound for the entirety of November, which is associated with no adverse public health advice for even the most vulnerable in the population (Table 2).
3 Measured Concentrations
3.1 Air Quality Statistics
Table 3 provides a monthly summary for particulate matter measured at Oxford St Ebbes and Oxford High Street.
| pollutant | min | median | mean | P95 | P99 | max |
|---|---|---|---|---|---|---|
| Oxford High St | ||||||
PM10 |
1.20 | 12.15 | 13.06 | 25.60 | 31.14 | 55.60 |
PM2.5 |
0.50 | 6.60 | 7.70 | 18.30 | 23.54 | 31.00 |
| Oxford St Ebbes | ||||||
PM10 |
0.82 | 7.15 | 8.14 | 16.93 | 18.43 | 28.32 |
PM2.5 |
0.35 | 4.28 | 5.32 | 13.23 | 15.68 | 24.84 |
3.2 Hourly Mean Values
The hourly particulate concentrations measured at Oxford St Ebbes and Oxford High Street are shown in Figure 4. This reveals some key features of measured particulate during the Bonfire Night period.
First, Oxford High Street almost always consistently measured higher PM than Oxford St Ebbes.
Second, Bonfire Night was associated with a peak in hourly mean PM, although this was cut across two days (from around 6 PM on Nov 4 through to 7 AM on Nov 5). This likely explains the low DAQI, which is a daily statistic.
Third, the peak in particulate matter on Bonfire Night is comparable to non-Bonfire peaks throughout November, with additional peaks on Nov 11, Nov 16, and Nov 25, among others.
3.3 Historical Comparisons
Figure 5 shows historic hourly particulate concentrations in early November, from 2019 through to 2023. Focusing on the 5th and 6th of November, particulate matter has typically remained relatively low throughout Bonfire Night, with the exception of 2020 which shows a clear peak in measured concentrations. Regardless, the DAQI at both sites remained in the “Low” band in all of the visualised years, with the highest index recoreded being 3 at both sites.
4 Summary
On Bonfire Night 2023, the daily air quality index (DAQI) across Oxfordshire remained within the “low” (1-3) band (Figure 2, Figure 3), which is associated with no adverse public health advice for even the most vulnerable in the population (Table 2). Time plots show some peaks in particulate matter on the evening of the 5th, but are not notably larger than other peaks throughout the rest of November (Figure 4). Low measured particulate concentrations can potentially be attributed to wet weather and relatively low winds.
These observations should not be used to dismiss the air quality impacts of fireworks on public health. The particulate concentrations measured by air quality monitoring networks are influenced by the distance between the fixed measurement sites and the locations of bonfire events (Figure 1). The DAQI as a statistic may be useful for pollutant events which last throughout a given day, but may underestimate the health impacts of a particularly short-lived but significant increases in pollutants. Despite the DAQI remaining “low”, Bonfire Night attendees may have experienced immediate, short-term effects of breathing air contaminated with particulates.
Historic Bonfire Night events did not appear to cause notably elevated concentrations in Oxford (Figure 5) with the exception of 2020. Still, future Bonfire Nights should continue to be analysed as varying meteorology, evolving legislation, and even the day of the week on which Bonfire Night falls will continue to influence particulate emissions as time goes on.