Using a data flow diagram, design a process controller for an environment monitoring system that collects data from a set of air-quality sensors situated around a city. There are 100 sensors located in 5 neighborhoods. Each sensor must be polled four times per second. When more than 40% of the sensors in a particular neighborhood indicate that the air quality is below an acceptable level, local warning lights are activated. All sensors return the readings to a central processing unit that generates reports every 15 minutes on the air quality.