AirTrack follows Wings of Survival to La Paz

Since our last update, they have ridden the Pacific coast into Los Angeles, crossed into Mexico, the third country of their nine-month expedition, and covered the full length of Baja: 1,403km in 13 riding days.

Following the whimbrels

The pair are retracing the migration route of GPS-tracked whimbrels along the Pacific Flyway. Whimbrels are a tipping point species: their global population has fallen by more than 80% in the last 50 years. The expedition's mission is to reconnect people with the natural world through adventure, science and storytelling.

How AirTrack follows the ride

Behind the scenes, Air Aware Labs has kept tracking the air along their route. AirTrack is plugged directly into their Strava, turning every ride into a private air quality breakdown, modelled along their GPS route for every hour in the saddle. Wherever we can, we check those numbers against the official air monitors along their road, and when the two disagree, the monitors win.

A smoggy welcome to Los Angeles

That check produced the headline of this update. On 3 October, as they rode the coast into Los Angeles, all five ozone monitors within 25km of their road went over the WHO limit for the day. Their highest eight-hour averages ranged from 123 to 139 µg/m³, against a limit of 100. Through August and September, not one monitor near their road had gone over it.

Ozone is the main ingredient in smog. It forms when sunshine reacts with pollution from traffic and industry, and it inflames the airways, especially when you're breathing hard on a bike. The monitors sat 7 to 22km from their coast road, so they show the air around the route that day rather than exactly what the riders breathed (US EPA AirNow data, still provisional).

Baja's empty roads

Baja told a very different story. On the long, empty desert roads from Ensenada to La Paz, traffic fumes fell to just 4% of the WHO guideline, the lowest of the whole ride so far. Fine particles stayed at about a fifth of the guideline.

Ozone, once again, came closest, at about 80% of its guideline, and the only monitor near their route, in La Paz, agreed. Because ozone is made by sunshine from pollution blown in from far away, even the quietest road can't fully escape it.

A pit stop for riders and birds

La Paz is a fitting milestone. The lagoon beside the city, Ensenada de La Paz, supports more than 20,000 shorebirds a year, including whimbrels, and is the last feeding ground for shorebirds heading south down the peninsula. Just like the birds, Timm and Leanna are refuelling here before the next leg.

Next, they cross to Mazatlán to regroup, then continue south towards Patagonia. AirTrack will keep tracking every stretch, so the story of the air they share with the whimbrels should keep unfolding as the journey goes on.