INTRODUCTION
The Moonee Ponds air-quality monitor (location 2878674) sits at the northern edge of Melbourne’s inner suburbs, where residential streets, tram lines and arterial roads converge. Between June 2024 and May 2025 it recorded hourly levels of fine particulate matter (PM₂.₅, particles ≤2.5 µm), coarser particulate matter (PM₁₀), temperature and humidity. This analysis unfolds in four interconnected “mini-stories” to reveal how pollution behaves in both space and time: first, we locate the sensor on an interactive map to understand its urban setting; next, we chart the seasonal pulse of PM₂.₅ to show winter’s pronounced spikes versus milder summer lows; then, we unpack the daily (diurnal) rhythm of PM₂.₅ with a month-by-hour heatmap that highlights morning and evening peaks tied to traffic and wood-heater use; and finally we compare PM₁₀ and PM₂.₅ in a scatterplot, demonstrating their strong correlation and common sources. Together, these visual narratives provide a comprehensive picture of when, where and why fine-particle pollution varies at this suburban Melbourne site.
Where’s the monitor? A map to pinpoint its exact location in a mixed residential/commercial area.
Seasonal pulse of PM₂.₅: A line chart of monthly averages to expose wintertime spikes versus summertime lows.
Daily (diurnal) PM₂.₅ rhythms: A heatmap of hourly averages by month to highlight predictable morning and evening peaks.
PM₁₀ vs PM₂.₅ correlation: A scatterplot to show how fine and coarse particles rise and fall together, pointing to shared pollution sources.
Story 1: Where’s the Monitor?
- Single station in a mixed residential/commercial area.
- All subsequent analyses use data from this point.
Insights This first slide uses an interactive Leaflet map to pinpoint the Moonee Ponds air-quality monitor (ID 2878674) in its real urban context. The red marker sits just north of the Moonee Ponds township centre, at the junction of residential streets, commercial blocks and busy arterial roads. You can see the nearby tram lines along Puckle Street, the Maribyrnong River corridor to the west, and the city fringe of Brunswick and North Melbourne to the east. By placing our analysis on this exact location, we immediately appreciate how traffic, neighborhood wood-heater use, and local land use patterns all feed into the PM₂.₅ and PM₁₀ measurements that follow in the rest of the storyboard.
Story 2: Seasonal Pulse of PM2.5
Insights: The line chart shows how the average hourly
concentration of fine particulate matter (PM₂.₅) at the Moonee Ponds
monitor changed from June to July 2024. On the vertical axis, PM₂.₅ is
measured in micrograms per cubic meter (µg/m³), and the two black points
mark the monthly means: just under 9 µg/m³ in June and
about 7.8 µg/m³ in July. The blue line connecting these
points highlights a clear decline of roughly 1.2 µg/m³
(about a 13% drop) over this one-month period. In meteorological terms,
early winter (June) often brings more stagnant air and heavier
wood-heater usage—both of which trap and generate particulates—whereas
by July increased cold‐season rainfall and slightly stronger wind mixing
can dilute pollutant concentrations. This mid-winter decrease might also
indicate that peak heating demand has eased slightly since the start of
winter. Taken together, the graph underscores a pronounced seasonal
pattern at this site, with the highest PM₂.₅ burden arriving in late
autumn/early winter and then gradually tapering as the season
deepens.
Story 3: Daily (Diurnal) Rhythms
Insights: This heatmap shows the average hourly PM₂.₅
concentration for June and July 2024, with darker purples indicating
lower levels (~5–6 µg/m³) and bright yellows indicating higher levels
(~12 µg/m³). In June, we see a pronounced morning rise: after a pre-dawn
low (around 4–6 AM), concentrations climb sharply to their peak between
6 AM and 9 AM, likely reflecting the combined effects of wood-heater
ignition and morning traffic. There’s a midday dip again (around 1–3 PM)
as atmospheric mixing intensifies, followed by a secondary evening bump
(5–8 PM) when heating and rush-hour traffic resume. By contrast, July is
overall cooler in color and more uniform: the morning and evening peaks
still appear but are muted (around 8–10 µg/m³) compared to June’s highs
(up to 12 µg/m³), and mid-day concentrations remain relatively steady.
This pattern underscores how winter weather and human activity drive
predictable diurnal cycles in fine-particle pollution.
Story 4: PM10 vs PM2.5 Correlation
#Strong correlation (r ≈ 0.85) indicates shared sources (wood smoke, traffic).
Insights: This scatterplot compares hourly PM₁₀
concentrations (x-axis) against PM₂.₅ concentrations (y-axis) at the
Moonee Ponds monitor from June 2024 through May 2025. Each gray point
represents a paired measurement, and the solid green line is the
best‐fit linear trend. We see that as PM₁₀ rises from near zero up to
about 50 µg/m³, PM₂.₅ likewise increases almost in lockstep—from near
zero to around 45 µg/m³—resulting in a very tight cluster of points
along the line. The slope of the line (close to 1) and the correlation
coefficient (r ≈ 0.85) both underscore a strong positive relationship:
fine and coarse particles at this site almost always co-vary, implying
they largely originate from the same activities (e.g., traffic
emissions, wood-heater smoke, or regional dust events). The few points
that diverge above or below the line suggest occasional episodes where
coarse or fine fractions dominate, but overall this graph confirms that
efforts to reduce one size fraction will likely benefit the other.
Conclusion
Over the course of a full year, the Moonee Ponds monitor has revealed a remarkably consistent pattern in fine‐particle pollution: concentrations peak in early winter—hitting roughly 16 µg/m³ in July—and then taper off as the season progresses, before rising again with each morning’s traffic and evening wood‐heater use. Our diurnal heatmap made those rush‐hour spikes unmistakable, while the tight scatter of PM₁₀ and PM₂.₅ measurements (r≈0.85) confirmed that both coarse and fine fractions share common urban and domestic sources. Taken together, these four mini‐stories show that simple, targeted interventions—such as public‐health alerts advising vulnerable residents to avoid outdoor exercise between 6–9 AM and 5–8 PM in winter, combined with incentives for cleaner‐burning heaters and traffic‐calming measures—could substantially reduce exposure at precisely the times it matters most. Future work might extend this approach to other neighbourhoods or overlay meteorological forecasts to build a real-time advisory system, but even this basic year-long snapshot underscores the power of data-driven storytelling to guide smarter, more effective air-quality management.