The exposed layer of the HDC3020 can sense small changes in moisture content in the air. If the volatile compound is absorbed by the sense layer, it may degrade the sensor and lead to incorrect measurements. The below section describes the effect of some volatile chemicals that have been exposed to the HDC3020. The purpose of this section is to determine the chemical effects on RH accuracy of the HDC3020 sensors. The devices were exposed to volatile organic compounds (VOCs) that are common in commercial, industrial, and residential cleaning products.

The list of chemicals can be divided into two subsections categorized based on the level of exposure: Saturation and recovery testing and long-term exposure testing. These two subsections have different test procedures, methods of application and exposure quantities.

These sections go over some of the results that were observed during testing. The devices were measured against a chilled mirror and swept at 30°C. An average of the error between 10% to 90% RH was measured and graphed in the following sections. The exposure quantity was minimum and the chemical concentrations were below industry standards, therefore the devices did not exhibit significant change in humidity measurement. However, during manufacturing and assembly processes, the humidity sensors should not be exposed to the chemicals outlined in the above section. Any significant exposure can damage the polymer and it will be difficult to recover the sensor back to operating conditions. If the device will be assembled where chemical exposure is high, then a HDC3021 can be the right solution. Another option is to consider the HDC3022 which comes with a permanent Polytetrafluoroethylene (PTFE) filter that can block particles up to 100 nm.

If salt contamination occurs and the RH error is greater at higher humidities, then the sensor can be washed with deionized (DI) water.