Like shooting fish in a barrel.
More and ‘worse’ than any air anyone ever breathes is smoking. Is maternal smoking associated with miscarriage?
Check out the table (below) from this study:
You can tell just from eyeballing the studies that there is no association between smoking and miscarriage. All the reported associations are either weak, statistically insignificant or otherwise statistically unreliable for deeply inhaled exposures to particulates that are much greater in concentration than anything in the air.
So there is no way there can be any association between ‘air pollution/ and miscarriage.