Now-a-days indoor air quality has been a vital concern, due to increased global warming, extensive usage of fossil fuels, rapid growth of transportation, and urbanization. Adequate and clean indoor air quality is essential for good health and comfort of individuals, especially considering that people who spends most of their time indoor. Due to lack of proper awareness, many people suffer from respiratory disorders like asthma, dust allergies, etc., because of prolonged exposure to the polluted environment. Hence, a real time monitoring and analysis of indoor air quality in the atmosphere has been the interest of recent topic. This paper deals with design and implementation of an Internet of Things (IoT) based system useful for monitoring levels of vital indoor atmospheric parameters like gaseous pollutants, particulate matter, temperature, and humidity using various sensors interfaced to microcontroller for analysis and processing for automation, display outputs on LCD, and communicates via Wi-Fi module using CoAP. The controller programming is done on embedded C language based on RTOS concept, resource sharing, and reduced time complexity with enhanced features. Monitoring and control mobile App is developed in Java language. Experiments were conducted to validate and support the development of the system for real-time monitoring and automation.