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The Mediterranean region under climate change

Jean-Paul Moatti
Stéphane Thiébault

Part 1. Mechanisms, observed trends, projections

Sub-chapter 1.4.5. Impacts of air quality on health

Texte intégral

1There is growing concern about the detrimental effects of air pollution on human health (WHO, 2013). However, data have only been collected in some countries in the Mediterranean region (WHO, 2014). A recent review systemically and qualitatively screened relevant papers and reports published between 2000 and 2014 on health impact of air pollution in the eastern Mediterranean region. The authors found only 36 published studies. A variety of indoor and outdoor exposures associated with various acute and chronic respiratory health outcomes were included. However, data were limited to a few studies in a few eastern Mediterranean countries and concerned both indoor and outdoor air pollution (ABDO et al. 2016). Several adverse respiratory health outcomes were positively associated with various indoor/outdoor air pollutants throughout the region. Respiratory health outcomes ranged in severity, from allergies and general respiratory complaints to lung cancer and mortality. In addition, although Mediterranean countries are highly exposed to dust storms and wildfires, their effects have rarely been studied. In this section, we present recent data on the consequences of exposure to particulate air pollution and related health impacts in the case of both anthropogenic and natural air pollution collected in the Mediterranean region. These include air pollution reduction scenarios.

Impact of air pollution on health in Bejaia (Algeria)

2In Algeria, monitoring of air pollution is limited to three big cities (Algiers, Annaba and Oran), and little is known about the impact of air pollution on health in most of the country. Ad hoc measurements of ambient concentrations of particulate matter taken in the Bejaia region in July 2015 indicated that the annual average PM10 (particulate mass concentration of particles smaller than 10 µm in diameter) and PM 2.5 (idem for particles smaller than 2.5 µm in diameter) levels in this urban zone exceed the World Health Organization (WHO) air quality guideline (AQG) values, the EU AQG and Algerian AQG. As expected, the highest 24-hr average concentrations (PM10= 103.7 ±15.1 µg m-3 and PM2.5= 35.7 ±9.5 µg m-3) were measured during peak traffic flow hours, pointing to a significant contribution of emissions from vehicles, which are generally old. These assessments of air pollution put forward that an estimated 55 deaths per year could be avoided by reducing the annual PM10 levels to the WHO AQG of 20 µg m-3. Furthermore, not exceeding the PM 10 WHO AQG would reduce respiratory and cardiac hospital admissions by 36 per 100,000 and 23 per 100,000, respectively (Benaissa et al. 2016). The same author previously showed that people who live in areas with high traffic density and high air pollution suffer from higher rates of asthma and COPD morbidity and mortality (Benaissa et al. 2014).

Impact of air pollution on health in Beirut (Lebanon)

3Another study was conducted in Beirut in 2012 where the main sources of pollution are vehicles and dust storms as there is no industrial activity in the vicinity. Results (Farah et al. 2104; Farah et al. 2016) showed that the annual average concentrations of PM10 and PM2.5 exceeded the annual average of WHO AQG (20 and 10 µg m-3, respectively) by 150% and 200%, respectively. The mean PM2.5:PM10 ratio for the entire study period was 0.61 ±0.12, indicating that in Beirut about 61% of PM10 is made up of PM2.5, i.e. that particulate air pollution is dominated by fine particles. The highest daily averages of PM10 and PM2.5 were measured in spring and summer (March to July) (Fig. 9), echoing the higher frequency of dust storms in this part of the Mediterranean at that period of the year. The correlation between particulate matter and nitrogen dioxide (NO2) indicated that vehicle exhaust emissions contribute an average of 93% of PM2.5 and 43% of PM10.

4Using data collected daily in 2012, the BAPHE (Beirut Air Pollution and Health Effects) study showed that total respiratory admissions were significantly associated with the same day (lag=0) level of PM10 (1.2% increase per 10 µg m-3 rise in daily mean pollutant concentration) and PM2.5 (1.6% per 10 µg m-3 rise in daily mean pollutant concentration) and that children and the elderly were at higher risk (Mrad Naklé et al. 2015). The results obtained in Beirut are similar to, and consistent with, those obtained in other international studies. Air pollution control is expected to reduce the number of disease admissions in Lebanon.

Figure 9
Relative distribution of WHO AQG exceedance days for PM10 and PM2.5 during the different months of the study in Beirut (from Farah et al. 2016).

Impacts of natural particles in the Mediterranean on health

5Since climate change will accelerate desertification processes in arid and semiarid regions, desert dust outbreaks and wildfires will increase substantially in both frequency and intensity in the near future in various regions of the world including the Mediterranean. The recent MED-PARTICLES (“Particles size and composition in Mediterranean countries: geographical variability and short-term health effects”;​medparticles/​) project studied the impact of dust storms and wildfires on human health in 13 cities of Euro-Mediterranean countries, including several on the Mediterranean coasts (Fig. 10): Barcelona and Madrid (Spain), Marseille (France), Bologna, Milan, Modena, Palermo, Parma, Reggio Emilia, Rome, and Turin (Italy), Athens and Thessaloniki (Greece). African dust outbreaks were highly frequent in southern sites during the period 2001-2011, i.e. occurred on 30% to 37% of the days, whereas they occurred on less than 20% of the days at northern sites (Stafoggia et al. 2016). The study also identified Saharan dust outbreaks as the largest source of PM10 in regional background southern sites of the Mediterranean (35% to 50% of PM10), with seasonal peak contributions to PM10 of up to 80% of the total mass. Significant increases by 10-µ g m-3 in non-desert and desert PM10 were associated with a lag of 0-1 day with increases in natural (non-accidental) total and cardiorespiratory mortality and hospital admissions (Stafoggia et al. 2016). The occurrence of wildfires assessed by satellite observations was also linked with health by the MED-PARTICLES project. A significant increase in natural and cause-specific mortality was observed on smoky days, with the biggest increase in mortality from cardiovascular diseases (Faustini et al. 2015). PM10 had more marked effects on cardiovascular and respiratory mortality on smoky days than on other days, suggesting particulate matter is an effective component of fire smoke. This new evidence for adverse health effects of natural sources reinforces the need for control of anthropogenic sources, especially on days when natural dust levels are high, to avoid individuals being subject to excessive exposure resulting from the accumulation of anthropogenic and natural air pollution.

Figure 10
Urban cities involved in the MED-PARTICLES (“Particles size and composition in Mediterranean countries: geographical variability and short-term health effects”) project.

Reducing air pollution in the Mediterranean region

6Recent data from the Mediterranean region showed that reducing air pollution is beneficial (Benaissa et al. 2016). According to the VIIAS (Integrated Assessment of the Impact of Air Pollution on the Environment and Health) project (, 34,600 and 23,400 are the mean numbers of annual premature deaths in Italy that can be attributed to PM2.5 and NO2, respectively (​sites/​default/​files/​ancona.pdf). Applying the 2020 Italian National Energy Strategy (NES) would prevent 17% of the PM2.5-, and 57% of the NO2-attributable deaths. However, compliance with the EU Directive for PM 2.5 would have an even higher impact with a 22% annual reduction in attributable mortality, with the highest reduction (-30%) in urban areas. For NO2, compliance with the EU Directive would result in a 25% annual reduction in attributable mortality, especially in urban areas (-31%). Like for ozone, VIIAS estimated 1,710 annual premature deaths from respiratory diseases due to long-term exposure, and 2,230 annual premature deaths from non-accidental causes due to short-term exposure. Applying the 2020 Italian NES would prevent 23% of the long term and 14% of the short term O 3 attributable deaths, especially in the south (-26% and -20%, respectively) and in rural areas (-27% and -21%, respectively).


7Studies on the impact of air quality on health conducted in the Mediterranean region underline the need to improve assessment of exposure and estimations of anthropogenic and natural (especially dust storms and wildfires) related health outcomes in countries where they have been neglected. A better understanding of the role played by meteorology in the direction and the extension of dust events in space and over time is also important. Prevention needs to be promoted, since it has been shown to be effective in reducing effects on health.

Table des illustrations

Légende Figure 9Relative distribution of WHO AQG exceedance days for PM10 and PM2.5 during the different months of the study in Beirut (from Farah et al. 2016).
Fichier image/jpeg, 121k
Légende Figure 10Urban cities involved in the MED-PARTICLES (“Particles size and composition in Mediterranean countries: geographical variability and short-term health effects”) project.
Fichier image/jpeg, 124k

© IRD Éditions, 2016

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