Air pollution monitor required

Began investigating the idea of an air pollution monitor for use in UK and Indonesia. Motivation is understanding polution levels in a "gang" (small street) microclimate in Jakarta Indonesia, and understanding pollution levels close to a waster water processing plant in Eastbourne UK.
Budget is a major factor.
Considering something based on a Raspberry Pi or Arduino or both.
Want to be able to read local values at least, but really want to automatically upload to the web.
Currently looking at: Circuitdigest.com's Arduino idea using

• MQ135
• ESP8266
• 16x2 LCD
• various resistors and a buzzer.