Time-to-time See The Air readers contact me because they want to know if some portable Air Quality monitors made in China worth an investment, so I decided to research and find out which of them is the best. First, I cross checked the features as they were presented online and I noticed that some of them have a laser Particulate Matter PM2.5 sensor, which is good, and some other use an optical one. With that in mind, I purchased the WP6930S.

These kind of products are quite economic and the reason for that is because there isn’t any support behind them. There isn’t a customer service either product support. Of course, don’t expect improvements over time with firmware updates because there aren’t any. My device came with the SW version 1.0.0EN and HW version 1.0.0V

Let’s dive in and analyze the device and the PM sensor.

The form factor is very good it fits in your hand like a TV remote control and the user interface is quite easy too. For the basic navigation you need to push the arrows, OK and ESC buttons. Then, there are four button below the screen and each time the function of the buttons change depending what the screen displays. A micro USB port for charging the device is on the right side and an ON-OFF switch on the left side.

Let’s see how accurate is the device next to the AirVisual AQ Monitor. Although the device has a log function that allows you to record all measurements, it doesn’t allow you to transfer the file on your PC/MAC via the USB port. As a result I had to take time-lapse photos for the PM2.5 measurments with the two devices one next to the other and manually create a chart. The value of R is: 0.8956 and the value of R², the coefficient of determination, is 0.8021. Let’s consider here, the non-accurate timing between the measurements that were taken by each device, which there can be a difference of up to 5 seconds, and the Brownian motion.

The device can store up to 500 points which equals to 41 minutes and 40 seconds if the device takes measurements every 5 seconds and it can store up to 16 hours and 40 minutes if it is set to take measurements every 120 seconds.

There are two “Pro” options which allow you to calibrate the device, one by leaving it to air fresh environment such as balcony, outdoors etc… for 10 minutes and the other to calibrate the sensors by adjusting with sliders the values so they can match values from other AQ monitors.

It uses the VSON PM010 sensor for PM1.0, PM2.5 and PM10 detection which is basically a PMS3003 Sensor developed by Plantower. When humidity is higher than ∼85% the PM readings are incorrect.

Conclusion

All in all, the device can offer some value to the costumers but it really bothers me the fact that you can’t transfer the log file to your PC for further analysis of the data.

In the next article I will try to a find out how well the formaldehyde sensor compares against the uRad A3.