Design and development af a lightweight low-cost sensor unit for the parallel measurement of particles, gaseous air pollutants, atmospheric pressure, temperature and humidity

There are frequent measurement tasks, where lightweight low-cost sensor units are of interest for the parallel measurement of several environmental parameters. Moreover, often measurements of environmental parameters are necessary not only at one specific point, but distributed over a large area or at different altidudes. In this case it makes sense to utilize lightweight low-cost sensor units. Because of the low price the can be produced in many exemplares und used at several places in parallel.

The Laboratory for Environmental Measurement Techniques (UMT) at the Duesseldorf University of Applied Sciences (HSD) has developed such electronic units with following features:

• They can measure particulate matter PM10, PM2.5, PM1, PNC and size distribution using particulate sensors of different brands, e.g. Alphasense sensors R2 or N3 or Sensirion SDS 30.
• Additionally they have analog interfaces so that they can be equipped with sensor units for gaseous pollutants, e.g, Alphasense sensors for SO₂, NO₂, Ozone and many other gases like CO₂ using Sensirion sensors.
• In parallel atmospheric pressure, temperature and humidity can be measured by additional dedicated sensors.
• The sensor units are equipped with a SD card memory and optionally with I²C or RS232 interface.
• Additionally the data can be transmitted in a wireless way to a server on 433 MHz, 868 MHz, 2.4 GHz ISM-band or via LTE or IRIDIUM.
• The main electronic unit is of lightweight design. Therefore the low-cost sensor units can be used easily on mobile platformes like drones or bicycles.
• The sensor unit has a low power consumption, so it can be operated independently for days or weeks, depending on the battery capacity.
• A GPS module enables a timestamp for the data and gives position and altitude.

Several fully installed measurement units have been tested by UMT groundbased at industrial and heavily polluted urban sites in Germany. Moreover, such a unit has been operated on a measurement drone for taking vertical and horizontal pollutant profiles. It is planned to use these sensor units also at volcanic sites in a mobile and stationary way. The low-cost sensor units have been intercompared with certified air pollution measurement systems to assure the data quality.