  We investigate local environmental effects from dark matter (DM) on
thermonuclear supernovae (SNe Ia) using publicly available archival data of 224
low-redshift events, in an attempt to shed light on the SN Ia progenitor
systems. SNe Ia are explosions of carbon-oxygen (CO) white dwarfs (WDs) that
have recently been shown to explode at sub-Chandrasekhar masses; the ignition
mechanism remains, however, unknown. Recently, it has been shown that both
weakly interacting massive particles (WIMPs) and macroscopic DM candidates such
as primordial black holes (PBHs) are capable of triggering the ignition. Here,
we present a method to estimate the DM density and velocity dispersion in the
vicinity of SN Ia events and nearby WDs; we argue that (i) WIMP ignition is
highly unlikely, and that (ii) DM in the form of PBHs distributed according to
a (quasi-) log-normal mass distribution with peak $\log_{10}(m_0/1$g$)=24.9\pm
0.9$ and width $\sigma= 3.3\pm 1.0$ is consistent with SN Ia data, the nearby
population of WDs and roughly consistent with other constraints from the
literature.
