# Development of a Smartwatch with Gas and Environmental Sensors for Air Quality Monitoring

## TL;DR

A smartwatch with gas sensors was developed to provide personal air quality monitoring with high sensitivity and discrimination.

## Contribution

A novel smartwatch device using MEMS gas sensors for personal air quality monitoring with low detection limits and good gas discrimination.

## Key findings

- The smartwatch achieved low detection limits for carbon dioxide and methane.
- Principal component analysis showed effective discrimination between toluene, xylene, and ethylbenzene.
- The device offers a portable and cost-effective alternative to traditional air quality monitoring systems.

## Abstract

In recent years, there has been a growing interest in developing portable and personal devices for measuring air quality and surrounding pollutants, partly due to the need for ventilation in the aftermath of COVID-19 situation. Moreover, the monitoring of hazardous chemical agents is a focus for ensuring compliance with safety standards and is an indispensable component in safeguarding human welfare. Air quality measurement is conducted by public institutions with high precision but costly equipment, which requires constant calibration and maintenance by highly qualified personnel for its proper operation. Such devices, used as reference stations, have a low spatial resolution since, due to their high cost, they are usually located in a few fixed places in the city or region to be studied. However, they also have a low temporal resolution, providing few samples per hour. To overcome these drawbacks and to provide people with personalized and up-to-date air quality information, a personal device (smartwatch) based on MEMS gas sensors has been developed. The methodology followed to validate the performance of the prototype was as follows: firstly, the detection capability was tested by measuring carbon dioxide and methane at different concentrations, resulting in low detection limits; secondly, several experiments were performed to test the discrimination capability against gases such as toluene, xylene, and ethylbenzene. principal component analysis of the data showed good separation and discrimination between the gases measured.