RECOMMENDATIONS FOR PLANNING
6.3.1 Industrial and Commercial Areas

Pollution Control Law and Building Law

On the basis of the responsible party principle anchored in federal pollution protection law, the individual emitting facility is the focus of measures for air pollution control, the most significant element of which is the pollution permitting process.

In relation to the permissible level of pollution in the area affected by a facility seeking a permit, the "Technical Guideline for Air Pollution Control" (the first general administrative specification under federal pollution control law, also known as "TA Luft") makes concrete requirements for consideration of the surrounding area, but from an urban development perspective does not distinguish between levels of required protection for areas affected by pollutant immissions. In contrast to noise protection practices, the immission (threshold) values in TA Luft are thus equally valid for all types of construction sites in accordance with § 1 (2) BauNVO.

The compatibility of an emitting facility with its surrounding area results solely from the validity of the permitting process under building law, in accordance with the Federal Building Use Ordinance (BauNVO) and the corresponding regulations of the site plan.

An area"s level of justified protection is measured by what is allowable in that area under planning law. To that extent, the existing classification of types of construction sites in §§ 2 to 10 of the BauNVO also contain a progressive ranking of immissions controls corresponding to the respective land use of a site. This relates to the sensitivity of the allowable land uses to both emissions and immissions.

According to § 15 (3) BauNVO, the permissibility of facilities in construction sites should be evaluated on more than just the process guidelines of the Federal Pollution Control Law (BImSchG) and the ordinances developed from it. Rather, it is noted that facilities requiring a permit under pollution control law can also be located outside of industrial areas, depending on the individual case. The typical view assumes that § 4 of the BImSchG allows permit-requiring facilities (typically manufacturing or other productive enterprises) without restriction only in industrial areas, whereas commercial areas and mixed-use areas are to be reserved for facilities not requiring permits.
Of particular note is the option foreseen under § 1 (4) BauNVO of dividing a construction site according to the types of permissible uses as well as the type of enterprises and facilities and their particular requirements and characteristics. This option of division can be employed to prevent the locating of air-polluting enterprises in special locations (e.g. in air exchange corridors or transient areas to other uses important for the urban climate), even in an industrial area. This corresponds to recognized principles of urban planning that fundamentally forbid the creation of new problem situations in the planning of new development.

§ 50 of the Federal Immission Control Act says that "in the case of regional planning projects and associated measures, the land earmarked for specific types of use shall be zoned in such a manner that harmful environmental effects ... on areas that are ... used for residential purposes as well as on any other areas worthy of protection are kept to a minimum. In the case of regional planning projects ... carried out in areas in which the immission limits and target values ... are not exceeded, one aspect to be taken into account shall be maintenance of optimum air quality."

North Rhine-Westphalia"s Clearance Decree could here be used as an aid in the practical realisation of the adequate designation of land use.

Immissions Climatology

In permitting processes for larger emitting facilities as well as in connection with prescribed accident analyses, immissions prognoses obtained by means of dispersal calculations or experimental simulations are highly important (cf. Chapter 4).

Fundamentally speaking, industrial and commercial areas should be located downwind from developments, with sufficient areas of green space in between. The main direction of wind indicates the compass direction from which the strongest and most frequent winds emanate on average. In southwestern Germany this is typically west through southwest. Thus it is in the easterly or northeasterly direction from a pollutant source that the highest concentrations of pollutants under free dispersal conditions are found. Under much less frequent low-exchange weather conditions the highest levels of pollutant concentration arise in the presence of weak or no winds (east through southeast wind directions). Average annual dispersal calculations therefore show a maximum level of proximate immissions primarily northwesterly from a pollutant emitter. The old rule of urban development concerning the main wind direction thus – with the noted restriction – remains valid.