Has onboard / plug-in PicoW which has GP8/9 hooked up for UART to the optional PMS5003. See schematic here: https://cdn.shopify.com/s/files/1/0174/1800/files/pico_enviro_pack_schematic.pdf?v=1664964820 Product page: https://shop.pimoroni.com/products/pico-enviro-pack?variant=40045073662035 Forum post presenting issue: https://forums.adafruit.com/viewtopic.php?p=1000995