Design of a Monitoring System for the identification of Gas Concentration in the district of Mi Perú – Callao, Perú

In recent years, the contamination of toxic gases in society is a very controversial problem because of the various consequences and effects they generate on health. There are several studies which highlight that the main polluting gases to the environment such as carbon monoxide, lead, cadmium, among others are the main causes of the increase in various acute diseases, such as pneumonia, or chronic diseases, such as cardiovascular diseases or lung cancer. That is why, faced with this problem, this research work proposes a monitoring system that determines the concentration of toxic gases, in such a way that it can contribute as an informative medium which can be implemented in various focused points where high rates of pollution are concentrated. The system has a very efficient MQ 135 gas sensor which includes a reading of 5 to 600 ppm (parts per million) at 3m with a temperature of 25ºC. It should be noted that it is important to keep the sensor on 24 hours beforehand to obtain a correct reading. Thus, concluding that this system of toxic gases can be easily applied to society because it is economical and because it has a free software which will be responsible for informing through a web server the level of ppm that you want to analyze at a certain point. Keywords- Toxic Gases, Pollution, Gas Sensor, Environment, Air Quality

UV-enhanced NO2 sensor using ZnO quantum dots sensitized SnO2 porous nanowires

ZnO quantum dots sensitized SnO2 porous nanowires were fabricated and designed for UV excitation gas sensor. The ZnO/SnO2 composite (SZQ1%) with the molar proportion of 1:100 exhibits excellent sensing properties to NO2 gas under UV irradiation at 40oC. The humidity stability of SZQ1% was also measured and discussed by DC reversed circuit and complex impedance curves. The gas sensing mechanism is well discussed and illustrated to the ZnO quantum dots sensitized and the increased photo-generated carriers under UV irradiation.

A dimethyl methylphonate sensor based on HFIPPH modified SWCNTs

In order to meet the requirements of ultra-fast real-time monitoring of sarin simulator with high sensitivity and selectivity, it is of great significance to develop high performance dimethyl methylphonate (DMMP) sensor. Herein, we proposed a DMMP sensor based on p-hexafluoroisopropanol phenyl (HFIPPH) modified self-assembled single-walled carbon nanotubes (SWCNTs) with field effect transistor (FET) structure. The self-assembly method provides a 4 nanometres thick and micron sized SWCNT channel, with high selectivity to DMMP. The proposed SWCNTs-HFIPPH based sensor exhibits remarkably higher response to DMMP than bare SWCNT based gas sensor within only few seconds. The gas sensing response of SWCNTs-HFIPPH based sensor for 1ppm DMMP is 18.2%, and the response time is about 10 seconds. What's more, the gas sensor we proposed here shows excellent selectivity and reproducibility, and the limitation of detection is as low as ppb level. The proposed method lays the foundation for miniaturization and integration of DMMP sensors, expecting to develop detection system for practical sarin sensing application.