An empirical and modelling approach to the evaluation of cruise ships' influence on air quality: The case of La Paz, Mexico

Maritime activity has diverse environmental consequences impacts in port areas, especially for air quality, and the post-COVID-19 cruise tourism market's potential to recover and grow is causing new environmental concerns in expanding port cities. This research proposes an empirical and modelling approach for the evaluation of cruise ships' influence on air quality concerning NO2 and SO2 in the city of La Paz (Mexico) using indirect measurements. EPA emission factors and the AERMOD modelling system coupled to WRF were used to model dispersions, while street-level mobile monitoring data of air quality from two days of 2018 were used and processed using a radial base function interpolator. The local differential Moran's Index was estimated at the intersection level using both datasets and a co-location clustering analysis was performed to address spatial constancy and to identify the pollution levels. The modelled results showed that cruise ships' impact on air quality had maximum values of 13.66 μg/m3 for NO2 and 15.71 μg/m3 for SO2, while background concentrations of 8.80 for NOx and 0.05 for SOx (μg/m3) were found by analysing the LISA index values for intersections not influenced by port pollution. This paper brings insights to the use of hybrid methodologies as an approach to studying the influence of multiple-source pollutants on air quality in contexts totally devoid of environmental data. [Display omitted] •Cruise ship's impact on air quality modelling (AERMOD-WRF).•The spatial pattern of pollutant concentration using low-cost analysers.•Differential Moran's I Index with local indicators of spatial association (DiLISA).•The influence of multiple-source pollutants on air quality was elucidated using a hybrid methodology.