/challenges-projects/design-challenges/sustain-the-world-design-challenge/b/blog/posts/gas-sensors-pressure-sensors-mq7-mq135-dps368-blog-9The MQ7 and MQ135 sensors operate with voltages of 5 Volts. and they must be hot to get best measurements.With the MQ135 sensor it was really easy to work. It is highly sensitive to different types of gases that are harmful to our health. I got pretten-USTelligent Community 12