Air Quality Monitoring Systems in Smart Buildings

by Aug 4, 2023#IoT, #HomePage

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Monitor and Manage Air Quality in Real Time

This page is part of the content series for IoT applications for smart buildings. Here we discuss air quality monitoring systems about the following essential aspects of smart buildings:

  • Improve health and comfort of building occupants
  • Create energy-efficient buildings
  • Optimize HVAC and ventilation systems in buildings
  • Comply with air quality standards and regulations

What Is Air Quality Monitoring?

Air quality monitoring is the process of measuring and analyzing the level of pollutants and harmful substances in the air, such as particulate matter, nitrogen dioxide, carbon monoxide, ozone, volatile organic compounds, and sulfur dioxide, for example.

Air quality monitoring helps identify the sources of pollution and helps to take action to improve people’s health inside buildings.

Air Quality Monitoring Equipment

Air quality monitoring is performed by sensors and data loggers that measure and create data about air quality.
Sensors are electronic devices that detect and collect data about specific pollutants and send data to data loggers.
Adafruit data logger shield
Data Loggers are electronic devices that capture data from sensors and store it to analyze and control air quality.

Rigorous air quality monitoring systems use special sensors and loggers designed for high performance and reliability. Data loggers are standalone devices or part of a quality monitoring system. They are designed for specific sensors (compatible), data logging capabilities, and communication protocols, and they usually include a microprocessor, storage, and battery.

Types of Air Quality Monitoring

You can monitor air quality indoors or outdoors. At Krasamo, we focus on building air quality monitoring apps for indoor use.

  • Ambient Air Quality Monitoring
  • Indoor Air Quality Monitoring

Air Quality Monitoring System Using IoT

An IoT-based air quality monitoring system is a system that monitors air quality using a network of air quality sensors that integrate with data loggers or mobile apps and transmit data in real time to a cloud platform, where data is stored, analyzed, and visualized for controlling and managing the air quality in real time.

Air Quality Monitoring with Embedded Processing

An air quality monitoring system can be created by connecting sensors and a data logger to an Arduino or Raspberry PI development board (using the appropriate interface), then writing a code to read sensor data and writing data and instructions to control the data logger.

Building an air quality monitoring system using Raspberry PI is a low-cost option. It’s an easy-to-program, highly customizable solution that connects with Bluetooth or Wi-Fi and scales as needed.

IoT developers at Krasamo have expertise in embedded systems programming as well as knowledge of sensors, protocols, and integration of sensors in a network.

Air Quality Monitoring Applications

Air quality monitoring applications can serve as data loggers by collecting and storing sensor data and enabling the measurement of pollutants in the air. In addition, these applications can perform specific functions depending on the sensor and environmental requirements. They can provide accurate and real-time information on air quality, comparing data and identifying trends and patterns in air pollution levels.

Air quality monitoring applications are customized with features according to the quantity and type of sensors (needs) and required sampling rates. They can record events under specific conditions (temperature, pressure, humidity), sensor measurement range, desired accuracy, and data storage, and they can track time and date of recordings (time stamps).

The air quality app displays and analyzes the air quality data in real time with a friendly user interface, retrieving historical data, creating alerts and notifications, and sharing data.

The air quality application may reside in the mobile app for real-time analysis (for personal air quality monitors), in a cloud-based platform for large-scale use cases, on a local server (for a specific location), or in an embedded system for low-power/low-cost IoT applications.

How to Log and Monitor Data in Real Time

You can create a customized logging system using Flutter Logger 1.3.0 for customizing the output log messages to a remote server, a console, or a file to meet your requirements. It allows customization of log levels and formats and is easy to integrate with Flutter applications.

The Flutter logger logs and monitors data from a data logger and creates the flexibility to output messages to a target output to meet specific app requirements.

The air quality sensor data is transmitted to a microcontroller or processor that logs it using the Flutter logger and sends it to the cloud or server. The mobile app retrieves the information from the cloud through APIs, MQTT, or HTTPS protocol and displays the data, charts, and graphs in the user interface.

The mobile app can have features to add or log contextual information back to the cloud, such as setting threshold parameters and controlling AC or air filtration according to the air quality level.

Contact Krasamo’s IoT consultants for building an air quality monitoring system.

Air Quality Monitoring Sensors Overview

Sensors for air quality monitoring provide data for accurate and reliable measurements of pollutants and substances in the air. Several types of sensors are designed for detecting specific pollutants with various accuracies, sensitivities, and costs.

Choosing a sensor for your IoT use case requires consideration of the type of sensor (optical sensors, electrochemical sensors, or metal oxide sensors, for example), the type of pollutant to detect, power requirements, compatibility, and required accuracy.

The sensor for your application must have the appropriate measurement ranges to determine the concentration level of pollutants and required accuracy.

Sensors are exposed to various concentrations of pollutants and are calibrated to ensure the desired accuracy. In addition, IoT engineers consider the interference from other pollutants or factors and how the data might be affected.

The frequency of sampling (sampling rate) or how often the sensor must measure is set according to the specifications of the application.

Sensor Data

Sensors transmit or output data in formats that must be compatible with the air quality monitoring system (i.e., data logger, air quality monitoring apps, or monitoring system).

Air quality sensors produce output data in analog signals that vary by concentration. These signals are then converted into a digital format, enabling data processing by microprocessors and eventual storage.

Other sensor types produce binary output/digital signals representing the value of the pollutant concentration. For example, some digital signal outputs come in pulse width modulation (PWM) format, Universal Serial Bus, or serial communication.

Smart sensors transmit data using wireless protocols (Bluetooth, Wi-Fi), cloud-based output, and Modbus output for industrial and commercial applications, such as SCADA systems, programmable logic controllers (PLCs), building automation systems (BAS), or distributed control systems (DCS).

Types of Air Quality Sensors

Following is a brief description of the types of air quality sensors. In most cases, they can integrate with monitoring systems, HVAC systems, air purifiers, thermostats, or other devices. Some of them need microcontrollers to process electrical signals and output data.
Following is a brief description of the types of air quality sensors. In most cases, they can integrate with monitoring systems, HVAC systems, air purifiers, thermostats, or other devices. Some of them need microcontrollers to process electrical signals and output data.

Particulate Matter Sensors (PM). Particulate matter sensors are cost-effective and widely used in industrial and commercial applications (e.g., HVAC and air purifiers). This sensor measures fine particulate matter in indoor spaces using a light-scattering technique that emits a laser beam that hits the matter and scatters the light for measuring and calculating the concentration.

Honeywell HPM Series Particulate Matter Sensor is laser-based
SEN55 from Sensirion: Environmental sensor node for PM, RH/T, VOC, NOx measurements
Honeywell HPM Series Particulate Matter Sensor is laser-based
SEN55 from Sensirion: Environmental sensor node for PM, RH/T, VOC, NOx measurements
Carbon Monoxide Sensors (CO). Carbon monoxide sensors measure carbon monoxide (CO) gas in the air and have sensing elements (metal oxide or electrochemical) that react to CO and create an electric signal. This type of sensor may come on a board and commonly integrates with HVAC systems.

Nitrogen Dioxide Sensors (NO2). Nitrogen dioxide sensors measure the concentration of nitrogen dioxide gas by reacting with electrochemical, optical, and metal oxide sensing elements.

Ozone Sensors (O3). Ozone sensors measure ozone levels in the air (formed when oxygen mixes with pollutants) and, similar to nitrogen dioxide, react to electrochemical, optical, and metal oxide sensing elements.

Volatile Organic Compound (VOC) Sensors. Volatile organic compound sensors measure organic chemicals emitted by products or materials, measuring by reacting with electrochemical, metal oxide, and photoionization (ultraviolet light) sensing elements.

Temperature and Humidity Sensors. Temperature and humidity sensors are used indoors to measure temperature and humidity levels in the air. Three types of sensors—resistive, thermal, and capacitive—use sensing elements that measure resistance or capacitance to calculate temperature and humidity levels.

Radon Sensors. Radon sensors measure the concentration of radon gas (a radioactive gas) in the air. They may be active or passive. Passive sensors measure a signal produced by radon decay (i.e., alpha track detectors expose a plastic film and measure the damage of the film or use a canister of charcoal that absorbs the gas). Active sensors use an ionization chamber that produces electrical signals, and scintillation detectors produce optical signals.

Formaldehyde Sensors (HCHO). Formaldehyde sensors measure the formaldehyde (HCHO) gas concentration in the air. (Formaldehyde is a gas produced by materials and household products.) These sensors have several sensing elements that create a reaction: electrochemical (creates a solution of electrodes and electrolytes), fluorescent (emits lights), or colorimetric (changes with color).

Dust and Particle Sensors. Dust and particle sensors measure the dust and particle matter concentration suspended in the air. This type of sensor includes gravimetric (using filters that weigh the dust before and after measuring) as well as optical and light-scattering sensors (measuring light scattered by particles with a laser). Dust and light sensors use a light source and detector of scattered light to measure the particles in the air.

Sensor Networks

A sensor network is a group of sensors connected wirelessly. They gather data from several locations, and they are connected to a central monitoring system.

IoT development teams work in the design and implementation of a network architecture that is scalable and energy efficient, providing top-notch data processing and analysis techniques.

About Us: Krasamo is a mobile-first digital services and consulting company focused on the Internet-of-Things and Digital Transformation.

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