This week, a piece of journalism from the other side of the Atlantic landed on my radar, and it's stayed with me since.
In three US states, chemical companies backed laws that stop regulators from using data collected by low-cost citizen sensors, even when that data shows real pollution. The official argument: community measurements aren't "reliable enough" for enforcement. The unofficial one, reading between the lines: they work well enough to be inconvenient.
Meanwhile, nearly six in ten US counties have no public air monitor left at all. The gap citizen sensors are filling is the same gap official networks are quietly abandoning.
Lisbon Finals isn't caught in that fight. Nobody is lobbying a parliament to stop a terrace station in Alvalade from counting decibels. But the logic underneath is the same one this project has run on since day one: measure what nobody else is measuring, publish it plainly, and let the numbers speak, not the interpretation of them.
That interpretation part matters more than it sounds. This station used to call some of what it measured a "violation." A visitor wrote in to point out, rightly, that the word implied more than the data could prove, since there's no way to know from a terrace which flights were authorized, which had a dispensation, or how each aircraft is legally classified. So we changed it: every page now says "alert," colour-coded, against a fixed threshold, with the method published next to the number.
Not because the data isn't worth defending, but because the strongest way to defend it is to never overstate what it proves.
A terrace with a Raspberry Pi and a microphone isn't going to make anyone rewrite a noise regulation. But it can keep showing up, month after month, with the same neutral measurement, for as long as it takes to matter to someone who can.
Source: https://www.theguardian.com/environment/2026/sep/10/us-chemical-industry-air-pollution-monitors