I'm a fan of the Espressif line of micros.  I was thinking that the ESP8266 would be a candidate, but the Plantower particulate sensor needs to be read with a UART.  The ESP8266 has only one UART which is pretty much dedicated to a serial-USB device.  Also, I'm planning to use an I2S MEMS microphone for audio recording - the ESP32 has a capable I2S peripheral to read samples from the microphone.  It also has multiple analog inputs which are needed to read the ozone and NO2 sensors - I'm cautiously optimistic that these  analog inputs are up to the task (whereas the single ESP8266 analog input is mostly unusable except for making crude measurements).

The WiFi capability will be useful to push sensor data to a MQTT server and cloud database. 

The ESP32 module which best suits this project is the Lolin D32 Pro.  This module has a built-in battery charger which I plan to use for recharging the LiPo battery. It also has a built-in micro SD Card slot - this will play into the logging of sensor data.  Lastly, it has the added advantage of 4MB of PSRAM, which will be useful for buffering audio samples.

https://wiki.wemos.cc/products:d32:d32_pro