Short-term monitoring of air pollutants at the port-urban exposure zone: a case study of Alexandria Port, Egypt.

Maritime ports are significant sources of greenhouse gas and air pollutant emissions that can affect air quality in adjacent urban areas. This study assesses the potential impacts of Alexandria Port activities on local ambient air quality, based on field measurements collected both inside and outside the port area. Two-monthly monitoring campaigns were carried out between May and October 2022 at 11 sites in the port and 13 sites in the urban area surrounding it, by using a portable multi-gas monitor and particulate sensors. The results are interpreted as screening-level spatial evidence, where measured pollutants included carbon dioxide (CO₂), carbon monoxide (CO), nitrogen oxide (NO₂), sulfur oxide (SO₂), ammonia (NH₃), volatile organic compounds (VOCs), particulate matter (PM2.5, and PM₁₀), from which air quality index (AQI) values were derived for selected pollutants. Spatial analyses reveal that port activities may be associated with high CO and NH₃ concentrations, with fuel and bulk fertilizer handling berths recording significantly higher concentrations than urban sites outside the port. In contrast, SO₂ and traffic-related pollutants measured outside the port appear to contribute to the urban background. Short-term exposure observations at one inner-port site showed the highest CO levels, with AQI values suggesting potentially unhealthy conditions during intensive cargo and ship-handling activities. Particulate matter levels were relatively low across the study area. Hourly meteorological observations from the station at Ras El-Tin were compiled for each field monitoring session from 14:00 to 03:00 the next day. The campaigns were dominated by moderate northerly to northwesterly winds with campaign mean wind speeds between 3.0 and 7.2 m s⁻1, serving as background for the atmospheric dispersion during the experiments. These results underline the air quality local processes controlled by both maritime and urban sources and the efficacy of a green port strategy implementation.