Long-term exposure to PM and all-cause and cause-specific mortality: A systematic review and meta-analysis

The objective of this review is to support the derivation of updated guidelines by the World Health Organization (WHO) by performing a systematic review of evidence of associations between long-term exposure to particulate matter with diameter under 2.5 µm (PM2.5) and particulate matter with diameter under 10 µm (PM10), in relation to all-cause and cause-specific mortality. As there is especially uncertainty about the relationship at the low and high end of the exposure range, the review needed to provide an indication of the shape of the concentration–response function (CRF).