Summary :

• Context and justification

Air pollution is a major public health and environmental problem. In 2012, according to the WHO, 8 million premature deaths worldwide were caused by chronic respiratory diseases, lung cancer, strokes, and heart diseases, all of which were attributed to air pollution. Of these deaths, 3.7 million were caused by outdoor pollution and 4.3 million were caused by indoor pollution (WHO, 2012). In southern countries, air pollution also significantly contributes to the onset and aggravation of chronic obstructive pulmonary disease (COPD) and the occurrence of acute and chronic respiratory diseases in children.

Outdoor air pollution caused by vehicles, industries, and rapid urbanization exposes the population to high concentrations of particulate matter (PM) with a diameter equal to or less than 2.5 µm (PM2.5). These PM particles increase the risk of cardiovascular diseases, acute respiratory diseases (such as pneumonia), and chronic respiratory diseases, primarily COPD. They also impact respiratory function in children and exacerbate asthma (WHO, 2016). Additionally, indoor air pollution, which is also a significant source of inhalation of respiratory pollutants, poses a major and additional health risk for people exposed to the use of biomass combustion energy, such as wood, charcoal, crop waste, and kerosene for cooking, particularly children, thereby increasing the risk of pneumonia (WHO, 2018).

Children are particularly vulnerable to respiratory diseases related to pollution. They have an increased sensitivity to atmospheric pollutants due to physiological and anatomical factors, which result in a higher deposition of particles in the lungs during a key period of lung development. Environmental exposure of children to pollution during periods of growth and lung development can lead to long-term irreversible deficits in lung function and expose adults to a high risk of COPD. In 2016, approximately 543,000 deaths of children under 5 years old and 52,000 deaths of children aged 5 to 15 years old were attributed to indoor and outdoor air pollution. Exposure to indoor air pollution increases the risk of pneumonia in children by nearly 2 times and is responsible for 45% of pneumonia-related deaths among children under 5 years old. In low- and middle-income countries, air pollution (both indoor and outdoor) accounts for more than 50% of acute lower respiratory infections in children under five years old.

The health effects of ambient air pollution are understudied in Africa compared to other continents. Few studies evaluate the association between air pollution and negative health effects, and most countries in sub-Saharan Africa do not have available data on pollution. Therefore, the majority of African cities lack pollution sensor networks and alert systems. Knowledge and risk perception of pollution are still very limited.

In cities such as Abidjan (Côte dIvoire), urbanization has not reduced the use of biomass burning for cooking and traditional fish smoking. This activity is particularly harmful to the health of women and their children, as they are intensely and repeatedly exposed to smoke and heat.

• Objective :

Evaluate the frequency of respiratory disorders and symptoms in children aged 5 to 10 years chronically exposed to indoor and outdoor air pollution in Abidjan, Ivory Coast, in 5 steps:

1. Measure the levels of indoor and outdoor pollution exposure in children and track the changes in exposure 5 years after the initial measurement.

2. Identify the socioeconomic determinants of this indoor and outdoor pollution exposure in children and its evolution.

3. Evaluate the frequency of respiratory symptoms, respiratory function, and the frequency of functional respiratory disorders and their impact on children.

4. Study the factors associated with functional respiratory disorders in children.

5. Assess the knowledge, viewpoints, and perceptions of adults and children regarding indoor and outdoor pollution.

• Main methods:

The cross-sectional study will focus on the children of women who were followed in a previous study in 2016-2017. It will involve 104 children for the quantitative part, and 5 to 8 women, 5 to 8 husbands, as well as 5 to 8 children aged 8 to 10 years from different families recruited for the qualitative part.