Abstract

Nowadays, almost half of the world's population is exposed to air pollution. Sources of pollutants come from energy production, households, industry, transportation, and so on. One of the targets of the sustainable development goals agenda is to pay special attention to air quality to obtain the comfort of residents in their daily activities. To determine the level of air pollution in a certain place, an instrumentation system is needed that can measure the levels of pollutants in that place. This paper describes the development of a low-cost air quality measurement system using the MQ-7 and MQ-135 gas sensors. The detected gases consist of carbon monoxide (CO), carbon dioxide (CO2), and ammonia (NH3). The information from the sensor is then processed by the NodeMCU ESP8266 module which can then be accessed via a certain internet-ofthings platform, namely ThingSpeak, and a cloud-based messaging service, namely Telegram. Experimental results show that the concentration of pollutants in a certain place can be known at any time from the ThingSpeak dashboard. In addition, an alert system is created to notify the user about the number of pollutant concentrations and the effects of the presence of these pollutant gases.

Keywords: air pollutants, MQ-7 gas sensor, MQ-135 gas sensor, NodeMCU ESP8266, ThingSpeak, Telegram.