In the case of air pollutants, the discussion of the immission situation of freight and individual traffic in Grorl cities has currently focused on formaldehyde and nitrogen oxides, which are harmful to health. In the case of stationary installations, air pollution control is being developed with partly city- and state-specific objectives. The future requirements in Germany are being, and in some cases have already been, newly regulated for this purpose.
In the past, biogas and special gas power plants were already conspicuous for their high carbon monoxide and especially aldehyde emissions. For this reason, the 2009 amendment to the Renewable Energy Sources Act (EEG) introduced a formaldehyde limit of 40 mg/Nm3.