Spatial analysis of the burden of lung cancer attributable to long-term PM2.5 exposure in Morocco: a national assessment using the WHO AirQ+ model.

This study quantified PM2.5-attributable lung cancer burden across Morocco's diverse districts using WHO's AirQ+ model. With lung cancer being a major public health concern linked to both smoking and air pollution, we aimed to provide localized evidence on PM2.5 impacts to guide policy decisions. We analyzed city-specific PM2.5 concentrations (2019 data), population exposures, and epidemiological risk functions for 46 urban and rural areas. The model calculated relative risks (RR), attributable proportions (AP), and case numbers with 95% confidence intervals (CI). Results revealed striking geographical disparities. PM2.5 levels varied from 7.1 µg/m3 in coastal El Jadida (RR = 1.02, 95% CI, 1.01-1.03; AP = 2.35%) to 28.4 µg/m3 in southern Errachidia (RR = 1.30, 95% CI, 1.17-1.42; AP = 23.29%). Other high-exposure areas included Ouarzazate (20.2 µg/m3; RR = 1.19, 95% CI, 1.11-1.25; AP = 15.82%) and Taourirt (19.0 µg/m3; RR = 1.17, 95% CI, 1.10-1.23; AP = 14.67%). While major cities showed moderate RRs (Casablanca: RR = 1.06, 95% CI, 1.04-1.08), their large populations contributed substantial case numbers (24 attributable cases). Distinct pollution patterns emerged-urban centers affected by traffic/industry versus rural areas impacted by biomass combustion. These findings demonstrate PM2.5's substantial contribution to Morocco's lung cancer burden, with population risks increasing by 2-30% across exposure gradients. The southern regions and certain rural areas emerge as priority zones for intervention. Results underscore the urgency for region-specific air quality strategies addressing dominant pollution sources (industrial emissions, vehicular traffic, residential burning). Strengthened monitoring systems and policies aligned with WHO guidelines are needed, particularly in high-risk areas. This spatial analysis provides critical evidence for Morocco's National Cancer Prevention Plan while highlighting needs for future research incorporating individual exposure data.