If you’re a runner, you probably think about distance, pace, maybe even elevation. But how often do you think about the air you’re breathing while you run?

A new 2025 study has done just that – mapping out which running routes across Australian cities have the cleanest air, and when the best time of day is to hit them. And it turns out what time you run is just as important as where you run.

The research, by longevity brand Simply Nootropics, cross-checked postcode air quality data with popular running trails from apps like AllTrails. The results show that Brisbane comes out on top, offering the cleanest air for runners across three major trails. And event better, if you lace up at 6 am, you’ll breathe in about 11% less air pollution than later in the day.

Dr Brian Ramos, neuroscientist and nootropics researcher at Simply Nootropics, says it’s something most people overlook.

“Many of us don’t think about what we’re breathing in while exercising outdoors. This data reminds us that environmental inputs are just as important as physical output. Runners in clean-air cities may be unknowingly gaining cognitive and longevity benefits every time they train. Your need for oxygen goes up when you do aerobic excersise, this is why air quality matters.”

Australia’s Cleanest City Running Routes

Brisbane officially takes the crown for cleanest-air city for runners, boasting an impressively low average Air Quality Index (AQI) of 1.113 – about 32% less pollution than Perth. Top spots like Mount Coot-tha Big Loop and the Goodwill Bridge Loop recorded near-identical AQI scores, making Brisbane the gold standard for lung-friendly running.

Hot on its heels are Melbourne (1.14 AQI), Adelaide (1.17), and Sydney (1.69) – all still offering excellent air quality by global standards.

Melbourne’s Albert Park Lake and Main Yarra Trail remain consistent clean-air choices, while Sydney’s harbourside routes, from Circular Quay to the Botanic Gardens, show that sea breezes really do make a difference.

Adelaide’s Burnside Quarry Loop also impressed, ranking just behind Melbourne with crisp air and scenic views just minutes from the CBD.

Even Perth, which ranked fifth, still scored well overall, with its Galup Loop Track and Law Walk offering beautiful coastal runs and respectable AQI levels.

The Best Time of Day to Run

The study found that air quality changes throughout the day, meaning the time you choose to run could make a noticeable difference.

• Brisbane: Cleanest air at 6 am (11.3% less pollution than average)
• Sydney: Best at 6 am, with air 16.5% cleaner than the city average
• Melbourne: Cleanest at 5 pm
• Adelaide: Peaks at 10 pm, with 8% cleaner air – perfect for night runners
• Perth: Major win for early risers – 6 am runs offer 26% cleaner air than the city’s daily average

Whether you’re chasing a PB or just some peace of mind, it’s worth checking your watch before you head out the door.

How do you choose when and where to run? Let us know in the comments below.