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How do air quality sensors measure the concentration of harmful gases?

Air quality sensors are devices designed to measure and monitor the concentration of harmful gases present in the atmosphere. These sensors play a crucial role in assessing and managing air pollution levels, which is essential for sustainable development and public health.

There are various types of air quality sensors available, each utilizing different technologies and methodologies to measure gas concentrations. Some common methods used by these sensors include:

1. Electrochemical Sensors

Electrochemical sensors are widely used for measuring the concentration of gases such as carbon monoxide (CO), nitrogen dioxide (NO2), and ozone (O3). These sensors work by utilizing a chemical reaction that occurs when the target gas comes into contact with an electrode. The resulting electrical current is then measured and converted into a gas concentration value.

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2. Photoionization Detectors (PID)

Photoionization detectors are effective in measuring volatile organic compounds (VOCs) and other gases that can be ionized by ultraviolet (UV) light. These sensors work by emitting UV light onto the gas sample, causing the gas molecules to ionize and produce a measurable electrical current. The magnitude of the current is proportional to the gas concentration.

3. Metal Oxide Sensors

Metal oxide sensors are commonly used for detecting gases such as carbon dioxide (CO2), methane (CH4), and volatile organic compounds (VOCs). These sensors operate by measuring changes in electrical conductivity when the target gas interacts with a metal oxide film. The gas concentration is determined based on the resulting change in conductivity.

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4. Infrared Sensors

Infrared sensors are effective in measuring gases such as carbon dioxide (CO2) and methane (CH4). These sensors work by emitting infrared light onto the gas sample and measuring the absorption of specific wavelengths by the target gas. The gas concentration is then calculated based on the amount of absorbed infrared light.

It is important to note that air quality sensors are often calibrated and validated against reference instruments to ensure accurate measurements. Additionally, these sensors can be integrated into larger air quality monitoring networks, providing real-time data for decision-making and policy implementation towards sustainable development.

Keywords: sensors, concentration, quality, measuring, infrared, measure, carbon, dioxide, target