Apparatus with a diesel particulate filter (DPF) will typically have:

A diesel particulate filter (DPF) significantly reduces the amount of soot and particulate matter emitted from diesel engines. This technology is designed to trap and remove harmful particles from the exhaust before they are released into the atmosphere. The primary purpose of the DPF is to ensure that the exhaust emissions are exceptionally clean, leading to a reduction in environmental pollution.

When operating correctly, apparatus equipped with a DPF will produce exhaust that is much cleaner compared to vehicles without such technology. This means there is a notable reduction in visible black smoke, which is indicative of incomplete combustion and high particulate emissions. The DPF's ability to filter out these particulates ensures that the exhaust released is substantially free of pollutants and contributes to improved air quality.

While other choices suggest varying levels of emission cleanliness, the option indicating that the apparatus produces very clean exhaust emissions and no black smoke accurately captures the effectiveness of a DPF in removing harmful exhaust components, highlighting the significant benefit of using this technology in emergency vehicles and other diesel-powered applications.