Nighttime–daytime PM10 source apportionment and toxicity in a remoteness inland city of the Iberian Peninsula

The distribution of daytime and nighttime sources PM10 collected from January to March 2021 at an urban background site in the city Bragança, Portugal, was performed using positive matrix factorisation (PMF). Additional data PM2.5, NOx meteorological variables were support interpretations. A solution with 5 factor profiles found: traffic (33%), dust (24%), biomass burning (21%), secondary inorganic aerosol (SIA) (12%) sea salt (10%). Mean concentrations 43.1 μg m−3 46.1 m−3, respectively. Nighttime dominated by residential combustion. Vehicle factors showed significantly greater contributions during day (+12% +4%, respectively), suggesting that exhaust non-exhaust emissions long-range transport are important contributors levels. In contrast, there no significant differences between night for SIA salt. Exceedances daily limit (50 m−3) PM2.5 (15 observed 22 (33%) 27 (40%) days campaign, respectively, mostly associated heating, but also Saharan outbreaks. application Aliivibrio fischeri bioluminescence inhibition assay ecotoxicity assessment allowed classifying 70% samples as toxic, especially those nocturnal period, indicating is one main responsible toxicity. Both estimated PMF multiple tracers this source statistically correlations toxicity units.