Troubleshooting My Philips Humidifier produces a bad smell If your Philips Humidifier produces an unpleasant smell, there might be a simple solution. Discover how to mend it yourself below. Plastic smell produced during initial usage The first few times you use your air humidifier, it may produce a plastic smell. This is normal and will fully disappear within a few days. The filter is dirty If the filter in your Philips Humidifier is dirty, it might cause a bad smell. To solve this, please clean the filter under the tap and descale regularly as indicated in the user manual.