Diesel is dirty and we must not be fooled by clever marketing saying it is clean just because you don't see any smoke
As I was standing in a queue at a McDonald's Drive-Thru today behind a diesel BMW that was just idling away I realised I don't often have my window open when driving and I was just thinking about how much NO2 was busy finding its way into my car. My own car is a hybrid and the whole 6 minutes or so I waited my engine was never running.
Just because I'm not seeing any smoke from the exhaust does not mean that toxic fumes are somehow magically erased. Imagine living next to a busy road, sitting in peak hour traffic for an hour, cycling, walking... When I think that in one Province in South Africa about 500 deaths are attributed to air pollution and over 100,000 people affected by respiratory conditions it makes me realise that the invisible killer is there all around us. Because we don't see it, it does not mean there is no harm.
From Wikipedia https://en.wikipedia.org/wiki/Catalytic_converter on catalytic converters: "or compression-ignition (i.e., diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst (DOC). DOCs contain palladium, platinum, and aluminium oxide, all of which catalytically oxidize the hydrocarbons and carbon monoxide with oxygen to form carbon dioxide and water. These converters often operate at 90 percent efficiency, virtually eliminating diesel odor and helping reduce visible particulates (soot). These catalysts are not active for NOx reduction because any reductant present would react first with the high concentration of O2 in diesel exhaust gas. Diesel exhaust contains relatively high levels of particulate matter (soot), consisting largely of elemental carbon. Catalytic converters cannot clean up elemental carbon, though they do remove up to 90 percent of the soluble organic fraction, so particulates are cleaned up by a soot trap or diesel particulate filter (DPF). Historically, a DPF consists of a cordierite or silicon carbide substrate with a geometry that forces the exhaust flow through the substrate walls, leaving behind trapped soot particles. As the amount of soot trapped on the DPF increases, so does the back pressure in the exhaust system. Periodic regenerations (high temperature excursions) are required to initiate combustion of the trapped soot and thereby reducing the exhaust back pressure."
Catalytic converters do not catch everything and many modern types of diesel are anyway still not compliant(more so in the 3rd world countries). From The Independent at https://www.independent.co.uk/environment/diesel-cars-air-pollution-emissions-which-tests-nitrogen-oxides-nox-a8496121.html "Some modern cars are emitting 25 times the legal levels of harmful pollutants into the atmosphere, according to a new report. Tests conducted on 61 new diesel vehicles found that 80 per cent of them exceeded the limits for nitrogen oxides (NOx)."
Diesel buses, diesel trucks, more and more diesel cars and we are assured they are all clean. Let's not continue to fool ourselves or live in ignorance. People are dying from this (and if not dying their medical costs are increasing). Don't believe the advertising. I'd rather have to stop every 150kmn to charge my EV than to drive a diesel!