Dumping Dirty Diesels in Latin America

Published: November 2014

Client: Natural Resource Defense Council (NRDC)

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Executive Summary

Efforts to reduce black carbon emissions have become an increasingly important component of national and international efforts to fight global warming, particularly as recent studies have concluded that black carbon is the second most powerful climate warming pollutant after carbon dioxide (CO2). Black carbon is one of four major Short-Lived Climate Pollutants (SLCPs) that live in the atmosphere for a relatively short period of time compared to other greenhouse gases, such as CO2. The others are methane, tropospheric ozone, and hydrofluorocarbons. Because these SLCPs stay in the atmosphere only briefly, reducing their emissions provides quick climate benefits.

Among the SLCPs, black carbon has the shortest lifetime—staying in the atmosphere for only days or weeks. Thus, reducing black carbon emissions provides benefits almost immediately.

More specifically, high-emitting diesel vehicles are the largest source of transportation-related black carbon emissions. This is a function of two factors: (1) the high concentration of black carbon within the carbon core of a typical diesel particle and (2) the increasing number of diesel vehicles. Open biomass burning is the leading source of black carbon emissions globally, but its combustion produces great quantities of organic matter, offsetting the warming potential of its black carbon emissions.


Although research into the specific environmental and climate impacts of black carbon emissions continues, there is an emerging consensus that, globally, black carbon emissions accelerate the melting of glaciers, snow, and ice and impact temperature and weather patterns in the Arctic and many alpine regions. In addition, black carbon emissions may also affect photosynthesis when deposited on leaves, reduce the quantity or quality of water available for agriculture, and reduce visibility due to suspended particles.

Research about the local climate impacts of black carbon emissions in Latin America reflects the global trends. For example, the surface area of the Andean glaciers has significantly reduced over the past three decades. Compared to 1964–1975, the loss of glacial surface area has nearly quadrupled in scale through 2010. This drastic decline in glacial ice impacts the 85 million people who live in the Andean regions of Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela. Of these people, 20 million rely on Andean glaciers for drinking water and agriculture. Shrinking glaciers are also a major concern for hydroelectric power generation in the region. In addition, black carbon emissions have a warming effect on the climate that reduces evaporation rates and atmospheric moisture, leading to continually decreasing rainfall throughout the Amazon Basin and surrounding areas.

Although these major trends have been established, research and data on the specific environmental impacts of black carbon in Latin America are scant. More focused and localized studies are needed to discern the full extent and implications of these emissions. Nevertheless, we know that the problem is serious, that cost-effective solutions exist, and that governments have the policy tools to implement those solutions now.


Reducing diesel pollution is an important tactic to improve human health. Black carbon is a component of particulate matter (PM), a complex mixture of extremely small particles and liquid droplets in the atmosphere. The most common source of transportation-related PM is incomplete combustion from diesel engines. The core of a diesel particle is typically comprised of black carbon, so the most common source of transportation-related black carbon is also incomplete combustion from diesel engines. Thus, transportation strategies designed to reduce black carbon will also reduce PM.

Health experts have found links between black carbon exposure and decreased vascular and respiratory functioning, including thrombosis, acute respiratory symptoms, aggravated asthma symptoms, decreased lung function, and lung inflammation. Moreover, the World Health Organization (WHO) has determined that outdoor air pollution, diesel exhaust, and particulate matter cause cancer.

Although there have been some studies (e.g., in Santiago, Chile), there is not enough information regarding black carbon’s specific health impacts in Latin America. Such studies should be a priority for policymakers since the expanding use of diesel fuels and vehicles in Latin America as a whole, coupled with the incredibly high rates of urbanization in the region, mean that more and more Latin Americans are being exposed to harmful fumes that damage their health and environment. One study has shown that by implementing specific measures to reduce black carbon and methane emissions, the Andean region could avoid 27,000 premature deaths annually. But more information is needed; the more we know about the local impacts of black carbon emissions, the better we can mitigate them.

Policy efforts to reduce diesel emissions to very low levels, therefore, represent a promising strategy to combat climate change and a range of public health issues.


The evidence clearly indicates that black carbon has widespread and dramatic impacts on Latin America: glacial melting in the Andes and Patagonia, declining moisture in the Amazon Basin, and illness and premature deaths from outdoor air pollution. Although additional black carbon-focused and health and climate studies are needed in Latin America to expand our understanding of these impacts, we know enough to strongly recommend that policymakers take action now.

Because black carbon is emitted as a component of PM, many tactics that can be used to reduce diesel PM in Latin America will be effective in reducing black carbon emissions as well, providing significant human health and environmental benefits at the local and global levels.

Taken together, the following strategies comprise a “systems approach” that has successfully reduced diesel PM and black carbon emissions in the United States, Canada, Europe, and elsewhere. There are three main components of this systems approach, as follows:

  • Clean fuels: The top priority for Latin America is to ensure widespread adoption of fuel standards that reduce sulfur levels to ultra-low levels (below 50 ppm). Reaching ultra-low sulfur levels will reduce PM emissions from all vehicles and enable the use of advanced vehicle emission control technologies that can eliminate more than 90 percent of black carbon emissions, compared to engines that are not equipped with these technologies. Currently, Chile is the only country to both adopt and implement ULSD standards. Mexico, despite adoption in 2009, has yet to implement its standards, though the country has signaled its intention to revise its fuel regulations this year and to implement an ultra-low sulfur requirement in the near future. Chile is the only country to both adopt and implement ULSD standards to sub-15 ppm levels. Colombia and Uruguay have 50 ppm sulfur standards.
  • Stringent emissions standards for new vehicles: Once ultra-low sulfur fuels are in place, Latin American countries can adopt vehicle emission standards for new vehicles that require the use of diesel particulate filters (DPFs) or comparably effective alternative fuels or advanced vehicle technologies that are emerging in markets around the world (e.g., vehicles powered by natural gas, hybrid-electric, or electric power). Because DPFs and other advanced emission controls are damaged or destroyed by high-sulfur fuels, adopting ultra-low sulfur diesel fuels is the necessary precursor to these new standards. Several countries have already made progress. By requiring urban buses to meet U.S. Environmental Protection Agency’s (EPA) 2007 standards, Chile is leading the way. Mexico has also signaled its intention to publish a rule in 2014 that would implement these (or even more protective) standards in the near future. Argentina and Brazil have Euro V standards for heavy-duty vehicles (HDVs) and others have Euro IV in place as well.
  • Complementary programs to reduce in-use emissions from existing vehicles: Because so many older, high emitting vehicles will remain on the road for years to come, countries should consider complementary measures to reduce in-use emissions from their existing diesel fleets. The most successful of these programs has targeted urban fleets, which focus on high-emitting, centrally fueled fleets. For example, in Santiago, Chile, more than 2,000 city buses have been retrofitted with DPFs. Low-Emissions Zones, which restrict a vehicle’s access to urban centers according to its emissions level, have proven successful in Europe through the establishment of incentives for cleaner vehicles. Small scrappage programs are being implemented in Mexico, Colombia, and Chile, under which owners of the oldest, dirtiest trucks receive financial incentives to retire them and replace them with newer, cleaner, more fuel-efficient models. More than 45 Latin American cities have implemented new Bus Rapid Transit routes that have created new public transit options that use clean buses to replace aging, high-emitting buses. Finally, in-use emissions monitoring helps ensure and improve fuel quality and supports in-use emissions maintenance programs.

In addition to the policy recommendations above, Latin America will benefit from more extensive air quality monitoring. Currently, only eight of the 15 countries surveyed in this analysis monitor for fine particulate matter (PM2.5), and most monitoring activities take place only in major cities. With improved air quality monitoring, public education and communications campaigns can educate the public about the link between diesel pollution, public health, and climate change, and thereby help to catalyze progress towards better government policies.

This report summarizes the latest research on black carbon and its role in global warming and consolidates research Natural Resources Defense Council (NRDC) and Gladstein, Neandross and Associates (GNA) conducted over the past year. The report and its appendices include country-specific research for Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Paraguay, Peru, Uruguay, and Venezuela, as well as case studies of successful programs in Chile, Mexico, China, and the United States.

If policymakers follow the systems approach we describe, which relies on proven fuels, technologies, and strategies, black carbon emissions will be significantly reduced in Latin America, providing important climate, public health, and other environmental benefits to hundreds of millions of people throughout the region, as well as globally.

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