<p>Open biomass burning has major impacts on the Earth system, including on air quality via the emission of primary fine particulate matter (PM_2.5). Its effect on secondary inorganic PM_2.5 formation is comparatively little investigated. Simulations with the EMEP MSC-W WRF atmospheric chemistry transport model reveal that global biomass burning emissions lead to elevated annual mean ammonium nitrate (NH₄NO₃) concentrations in densely populated regions where biomass burning mostly does not occur. These regions include eastern USA, northwestern Europe, the Indo-Gangetic Plain and eastern China, where NH₄NO₃ conditional on biomass burning emissions constitutes between 29% and 51% of the annual mean PM_2.5 conditional on biomass burning emissions. Biomass burning emissions of CO, NO_<i>x</i> (NO and NO₂) and volatile organic compounds perturb the HO_<i>x</i> (OH and HO₂) cycle globally, such that there is increased oxidation of anthropogenic NO_<i>x</i> to HNO₃. This results in additional contributions to local-scale secondary NH₄NO₃ in areas with high emissions of anthropogenic NO_<i>x</i> and NH₃. These teleconnections increase, by up to a factor of two, the contribution of biomass burning emissions to long-term PM_2.5 concentrations, which measurements alone cannot identify as an impact of biomass burning activity. This may become relatively more important as anthropogenic sources of PM_2.5 are reduced and as the wildfire component of biomass burning increases under climate change.</p>