Air pollution levels in South America

South America is a vast continent with distinct geographic features ranging from the Amazon rainforest to the Andes mountains. A high fraction of its population lives in dense cities, many of them with informal settlements, strong infrastructure challenges, and moderate-to-high air pollution. Traffic emissions are the most important threat to air quality and its human health burden. Consequently, urban areas dominate air quality monitoring, and significant data gaps exist in rural areas and globally significant natural environments. In addition, biomass burning events are impactful across the continent, in tropical areas during the first quarter of the year, and in the South during the third quarter. There are large differences in size and effectiveness of air quality monitoring systems, with Chile and Brazil having the strongest infrastructure, followed by Peru and Colombia. Available data shows that particulate pollution in many cities has been decreasing in the last 10 to 20 years as a response to air quality legislation and management programs. However, secondary pollutants such as ozone show increasing trends in cities like Santiago de Chile and Sao Paulo. Conversely, populations in small cities and rural areas, who rely on biomass for heating or cooking, face elevated levels of indoor air pollution. To meet challenges ahead, there are needs for i) more and better air quality monitoring; ii) strategic network design; iii) standardized air quality trend analysis; iv) increased air quality modeling capacities; v) planned adoption of air quality guidelines; and vi) innovative adoption of emerging technologies.