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These risks and health effects are not equally distributed in the population. People with previous disease conditions, children under five, and adults between 50 and 75 years of age are the most affected. Poor people and those living in situation of vulnerability, as well as women and their children using traditional biomass stoves for cooking and heating are also at a higher risk.  

There are short-term and long-term effects of air pollution on health, being long-term and life-long exposure the most significant to public health. The majority of the deaths attributable to air pollution in the general population are related to non-communicable diseases. In effect, 36% of the deaths from lung cancer, 35 % from chronic obstructive pulmonary disease (COPD), 34 % from stroke, and 27% from ischemic heart diseases are attributable to air pollution. However, the highest impact is on infant mortality, as over half of deaths among children less than 5 years old from acute lower respiratory infections (ALRI) are due to particulate matter inhaled from indoor air pollution from household solid fuels ()

The Americas is the most urbanized Region in the world (). 79% of the LAC population lives in towns and cities with more than 20 000 inhabitants (Economic Commission for Latin America and the Caribbean, ECLAC, 2014). This represents a major drive for high energy demands, including for services and for the production and consumption of materials and goods, transportation and for mobility, all of which contributes with air pollution. Transportation of goods and human mobility are mainly based on individual solutions, which demands high energy consumption with low efficiency. Furthermore, largely unregulated city dumpsites for solid waste, or the absence of public policies for the sector, represent not only a source of methane emissions and vector breeding sites, but also large quantities of fine particulate matter from accidental and non-accidental burning of the waste, with potential large contributions to air pollution in urban settings. Burning crop fields is still legal and is widely practiced in many countries, which can also contribute to bad air quality. Globally, household energy is an important source of outdoor air pollution as well. Household air pollution (HAP), mainly from cooking in traditional open fire stoves, is responsible for 12% of global ambient fine particulate matter pollution (PM2.5)  (). 

Policies to reduce air pollution can provide health benefits directly from related ill health; and indirectly from reduced ozone and black carbon effects on extreme weather and agricultural production (which affects nutrition and food security). On the other hand, healthy choices such as healthier diets including increased consumption of plant-based food and reduced consumption of red/processed meats have immediate health benefits, while lessen the demand for livestock products, which is associated with emissions of methane. Policies and investments on sustainable public transportation such as the bus rapid transit (BRT) based on lower emission technologies, walking and cycling networks, can also have immediate health benefits by promoting safe active travel, reduced levels of air pollution and noise, and reducing traffic-related injuries, but will also provide substantial reductions in CO2 emissions as well. These are examples of health promoting strategies with the best potential co-benefits for health and the climate, with the best benefits seen at local level ().

Other examples of these policies are: shifting to cleaner heavy duty vehicles and low-emissions vehicles and fuels, including fuels with reduced sulfur content; implementing stricter emissions and efficiency standards for both particulate matter and ozone precursors including oxides of nitrogen (NOx). Clean household energy solutions also offer a range of benefits, including reduced exposure to household and outdoor air pollution. ().

The theme of air pollution has been object of discussion at the World Health Assembly, that approved a resolution and a roadmap on air pollution () and (). Targets and indicators for the  in health (Goal 3), cities (Goal 11) and energy (Goal 7) were identified in resolution WHA68.8, and four of those indicators are already currently being reported in WHO databases. 

There are many resources to support the development of a knowledge-based platform for action, such as the , and the . Some countries are actively engaged in this endeavor to guarantee clean air for all. An example of this effort is the platform for action "". However, a much stronger engagement of the health sector is needed to implement the global agenda and mitigate the risks posed by air pollution and climate change in the Americas.

There are large differences among countries in the Region of the Americas regarding the adoption of the Air Quality Guidelines () of WHO. The main air pollutants regulated in the Region are PM10, PM2.5, NO2, Ozone, and SO2. PM10 is regulated in 21 countries; NO2, in 20 countries; and PM2.5, in 15 countries. Only Canada, the United States, Guatemala, Peru and Bolivia have adopted the WHO-AQG or lower levels for PM10 in their national legislation and, only Canada, the United States and Guatemala for PM2.5. 

Enforcement and control of the existing regulations in also limited, as only 19 of the 35 countries in the Region of the Americas provide information on ground level air quality measurements. Furthermore, the majority (84%) of the towns and cities with air quality monitoring sites are located in high-income countries. Table 1 present the number of towns and cities with monitoring sites for fine particles (PM10 and PM2.5) in the Region grouped by income level (Country income grouping is based on the ).

Table 1 - Total number of towns and cities in WHO AAP database in 2016, by income groups in the Americas

AAP = Ambient Air Pollution; LMI = Low and Middle Income countries; HI = High income countries. Source: .

In LAC, only 24 out of 43 cities with one million or more inhabitants have measurements of PM10 (56%), and only 16 for PM2.5 (37%).  Table 2 shows the distribution of the cities with monitoring sites for fine particles in LAC according to population size (); Table 3 shows the WHO guidelines for Ambient Air pollution (WHO AQG) and Table 4 shows the compliance with WHO AQG for annual median exposure levels of fine particles in these cities (). 

Table 2 - Number of cities in LAC (?100 000) with ground level monitoring sites of fine particles (PM10 and PM2.5)

Table 3- 

Table 4- Compliance with WHO AQG for annual median exposure levels of fine particles in LAC cities with 100 000 inhabitants or more with ground level monitoring sites of fine particles (PM10 and PM2.5). 

When comparing compliance with WHO AQG between HI and LMI countries in the Americas, more than 80% of the towns and cities assessed in HI are below the guidelines, while less than 10% of them in LMI were below the guidelines. Figure 1 show the distribution of the modelled PM2.5, where the concentration of air pollutants is clearly higher in LMI countries. For additional information on the methodology for modelling PM2.5 see: Ambient air pollution: A global assessment of exposure and burden of disease ().


Figure 1: Modelled levels of PM2.5, Region of the Americas. Source: .