Air quality comparison · Australia, 3290 km apart
Perth vs Sydney Air quality index (AQI) today
Perth has cleaner air than Sydney right now: AQI 25 (Good) against 31 (Good).
Both sit in the same EPA band, so the health advice is the same for each today. Over the past 6 days, on modeled daily averages, Perth averaged AQI 39 against 46, and it was the cleaner of the two on 5 of those days. Sydney has lost more forest since 2001. Sydney has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Perth25Sydney31
Head to head
Perth vs Sydney at a glance
Perth is ahead on 4 of 6 measures, and Sydney on 2. The better figure in each row is marked.
| Perth | Sydney | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 25 (better) | 31 |
| PM2.5Fine particles, µg/m³. | 4.5 (better) | 5.6 |
| Past week's averageUS AQI, 6 days. | 39 (better) | 46 |
| Forest lost since 2001Within 10 km of the center. | 78 ha (better) | 92 ha |
| Tree coverWithin 2 km of the center. | 18.1% | 28.3% (better) |
| Trees still neededTo reach a healthy canopy. | 30.3K | 3.8K (better) |
Air quality today
What is the air like in Perth and Sydney right now?
Perth has cleaner air than Sydney right now: AQI 25 (Good) against 31 (Good). PM2.5 is setting the index in both.
Both readings come from nearby ground stations.
PerthSydney
Concentrations at the same moment as the index above, for the pollutants both places report. Lower is better. The dark marks on the PM2.5 and PM10 rows show the WHO's 24-hour guidelines (15 and 45 µg/m³).
The past week
Which had cleaner air over the past 6 days?
Over the past 6 days, on modeled daily averages, Perth averaged AQI 39 against 46, and it was the cleaner of the two on 5 of those days. A single reading can catch a city on a bad afternoon; the week says whether it was the weather or the place.
- Cleaner days
- Perth5Sydney1
- Average AQI
- Perth39Sydney46
- Worst day, AQI
- Perth43Sydney60
The daily numbers (6 days)
| Day | Perth | Sydney |
|---|---|---|
| Nov 6 | 41 | 54 |
| Nov 7 | 41 | 44 |
| Nov 8 | 43 | 26 |
| Nov 9 | 27 | 37 |
| Nov 10 | 43 | 55 |
| Nov 11 | 37 | 60 |
Daily averages from the CAMS atmospheric model for both places, so the week compares like with like. They can differ from today's reading at the top of the page wherever that comes from a ground station.
What it means today
Is it safe to go outside in Perth and Sydney today?
Air quality is satisfactory for everyone. Both are in the same EPA band today (Good), so the advice is the same.
Exercise outdoors
A good day to be active outside.
Windows
Open them to air the house.
Masks
Not needed.
Air purifier
Not needed.
Against everywhere else
How do Perth and Sydney compare with the rest of the world?
Right now Perth's air is cleaner than 83% of the 5,420 places Airleaf tracks, and Sydney's is cleaner than 77%. Within Australia, that is 50% and 30% of its 21 measured places.
Cleaner air than…
- Perth
- Beats 83%
- Sydney
- Beats 77%
More tree cover than…
- Perth
- Beats 42%
- Sydney
- Beats 65%
Includes model estimates as well as station readings, so it can differ from our most polluted and cleanest air rankings, which use station readings only.
Deforestation · 2001–2025
Which has lost more forest, Perth or Sydney?
Sydney has lost more: about 92 ha of forest within 10 km of its center from 2001 to 2025, against 78 ha around Perth. 27 ha of that was cleared for good, for farms, mines or towns.
Measured within 10 km of each center, from the yearly satellite maps of forest loss: a wider circle than the one for tree cover, because forest is usually lost at a city's edges.
Worst year: 2007, with 10 ha lost.
Worst year: 2020, with 16 ha lost.
| Perth | Sydney | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 78 ha (better) | 92 ha |
| Share of its forestOf what it had in 2000. | 9.3% | 4.7% (better) |
| Cleared for goodTurned into farms, mines or towns. | 70 ha | 27 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (90%) | Wildfires (59%) |
Satellite timelapses
Watch both change, year by year
A clear satellite photo a year of the land around each city. Press play, turn on the forest cleared since the first year, or drag the before and after.
Perth
2017: satellite photo from March 2017 of a 5 × 5 km area in the city center.
Sydney
2018: satellite photo from December 2017 of a 5 × 5 km area about 7 km northeast of the city center.
Trees
Which has more trees, Perth or Sydney?
Sydney has more tree cover: 28.3% of the land within 2 km of its center against 18.1% around Perth, or about 63,657 trees against 46,116.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Perth | Sydney | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 46.1K | 63.7K (better) |
| Trees still neededTo reach the target. Fewer is better. | 30.3K | 3.8K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 1.0M kg | 1.4M kg (better) |
Tree cover on the satellite image
The same 2 km radius around each center, with the tree cover the satellite found marked on it.
Reading these numbers
How this comparison is made
Air quality index
The US EPA index, computed from current pollutant concentrations: ground stations where a place has them nearby, and the CAMS atmospheric model everywhere else. It moves hour to hour, so it is a snapshot rather than a verdict on either place. The guideline marks are from the WHO's 2021 air quality guidelines.
Trees and forest
Tree cover is the share of ground under canopy within 2 km of each center, read from Sentinel-2 satellite imagery at 10 m detail. It measures that circle, not the whole municipality, which is what makes the two comparable. Forest loss comes from the University of Maryland's Global Forest Change maps.
More on the method on the About Airleaf page.
Frequently asked
Perth vs Sydney: your questions answered
Is Perth cleaner than Sydney?
On air quality, yes, right now: Perth reads AQI 25 against 31, a gap of 6 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. Over the past 6 days, on modeled daily averages, Perth averaged AQI 39 against 46, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Perth and Sydney today?
The advice is the same for both today. Air quality is satisfactory for everyone. Perth reads AQI 25 and Sydney reads AQI 31.
Which has lost more forest, Perth or Sydney?
Sydney has lost more: about 92 ha of forest within 10 km of its center from 2001 to 2025, against 78 ha around Perth. 27 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Perth or Sydney?
Sydney has more tree cover: 28.3% of the land within 2 km of its center against 18.1% around Perth, or about 63,657 trees against 46,116. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Perth and Sydney need?
Perth needs about 30,319 more to reach its canopy target of 30%, and Sydney about 3,824 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Perth and Sydney measured the same way?
The method is the same: the US EPA index for air, and Sentinel-2 satellite imagery at 10 m detail over an identical radius for trees. Both readings come from nearby ground stations. Nothing is adjusted for population, city limits or climate.
How often does the Perth vs Sydney comparison update?
The air readings refresh about once an hour, and each reading's local time is shown at the top of the page. Tree cover comes from the latest clear satellite image of each area (Mar 6, 2026 and Mar 10, 2026), and the forest figures are published yearly.
Keep going
Compare them with somewhere else
Build your own
Compare Perth with somewhere else
This place
Perth