Recently, UN releases the report which tells about reducing global health risks through mitigation of short-lived climate pollutants
WHAT ARE SLCPS?
Short-lived climate pollutants (SCLPs), found in ambient (outdoor) and household air pollution, produce strong climate change effects but only remain in the atmosphere briefly –for a few days to about a decade. The short life span of SLCPs means that assertive action now to reduce emissions can rapidly improve both air quality as well as slowing the rate of near-term climate change.
The main SLCPs of direct concern to health include black carbon (or ‘soot’), methane and ozone, which all contribute to both health-harmful air pollution and global warming. . Black carbon (BC) makes up a significant portion of fine particulate matter, the air pollutant most associated with premature death and morbidity. Ozone has significant adverse impacts on respiratory health, and methane contributes to ozone formation.
Mitigation experts believe that firm actions reducing SLCP emissions could slow the pace of climate change by as much as .5⁰ C over the next few decades. Even so, it is important to note that SLCP reduction measures complement, but do not replace, the actions needed to reduce longer-lived CO2 emissions for climate stabilization.
Open fires, (including wildfires, deliberate forest/brush burning, and burning of urban and crop waste), comprise the largest single source of black carbon emissions. Fuel combustion in residential and commercial buildings, as well as transport, account for approximately 80% of black carbon emissions from human activities related to energy production and use. Emissions from diesel, biomass and kerosene combustion are among the sources with the heaviest black carbon concentrations, and accordingly have been identified as priority sources for reducing emissions that contribute to near-term climate change.
Particulate emissions from other sources, such as coal-fired power plants, are also a source of black carbon emissions, but here BC is co-emitted with other pollutants that have a climate “cooling” effect so that mitigation in this sector would have less of an impact on near-term climate change. In health terms, however, mitigation efforts that reduce fine particulates from other sources can, of course, be beneficial, and may also may reduce CO2 and thus longer term climate change.
Ozone is not emitted directly but develops when a number of “precursor” pollution emissions interact in the presence of sunlight. Precursor emissions often include; methane, oxides of nitrogen, volatile organic compounds, and carbon monoxide.
Ozone is the second SLCP that causes adverse respiratory effects, with impacts ranging from changes in lung function and increased incidence of asthma to premature mortality. Methane is a powerful SLCP in and of itself, mainly produced from the agriculture sector, including livestock production, waste sector, and as a byproduct of fossil fuel extraction and distribution. Methane emissions impact on health through their role in ozone formation.
WHAT IS THE IMPACT OF SCLPS ON HEALTH?
Since SLCPs contribute to ambient levels of ozone and PM2.5, SCLP emissions are directly associated with cardiovascular and respiratory diseases, including heart disease, pulmonary disease, respiratory infections and lung cancer. SLCP emissions thus contribute significantly to the more than 7 million premature deaths annually linked to air pollution.
Indirectly, the SLCPs ozone and black carbon reduce plant photosynthesis and growth, thus decreasing agricultural yields, which in turn threatens food security. They also affect weather patterns and the melting of snow and ice, which may harm and endanger health through extreme weather events such as floods.
CAN SLCP EMISSIONS BE REDUCED?
Yes, SLCPs are emitted from a variety of sources in the transport, agriculture, waste management, residential and industrial sectors, so there a range of mitigation opportunities that exist that can be highly beneficial for health.
In fact, addressing SLCPs has distinct advantages insofar as health benefits from many measures can be enjoyed in the near term, and along with slowing the rate of near-term climate change, measures can be very complementary with longer-term CO2 emissions reductions required to reduce long-term climate change. So these are ‘win-win’ policies for the health, environment and climate sectors.
WHAT ARE THE MITIGATION ACTIONS?
The report covers many different strategies, providing indicative “ratings” of potential health and SLCP mitigation benefits for 19. The CO2 reduction potential of the same strategies was also considered, since SLCP mitigation is seen as complementary to mitigation of CO2 emissions required to stabilize climate and ensure the health of future generations. Four strategies were identified which appear to have the largest aggregate potential for health and SLCP mitigation benefits as well as reducing CO2.
- Policies and investments that prioritize dedicated rapid transit and walking and cycling networks in compact cities can promote health in multiple ways, including reduced air pollution exposures, reduced injury risks and greater opportunities for safe active travel.
- Encouraging healthier diets rich in plant-based foods and low in red and processed meats among affluent populations at risk of a range of diet-related noncommunicable diseases will have a positive effect on health and will also reduce emissions.
- Provide and promote the use of clean and efficient cook-stoves and fuels, and cleaner energy sources, to the approximately 2.8 billion low-income households that currently rely on solid fuels for heating and cooking.
- Reducing vehicle emissions of both particulate matter as well as ozone precursors (e.g. NO2) by implementing stricter vehicle and fuel emissions and efficiency standards.
Along with these four, however, many other SLCP measures identified in this report are also very beneficial to health. Examples include improved waste management strategies, more energy efficient homes and buildings, phasing out kerosene lamps and greater reliance on clean light and power sources, using including renewable energy, for homes and health clinics, cleaner brick industries and coke ovens, etc.
Measures outlined can reduce many other types of health risks, ranging from: housing related diseases associated with exposure to extreme heat, cold or damp; sanitation-related diseases; air pollution from kerosene and generator fumes; work-related diseases, and so on.. These approaches are also discussed in detail, by sector.
IN WHAT WAYS WILL REDUCING EMISSIONS BE BENEFICIAL FOR HEALTH?
In summary, there are three key ways in which reducing emissions of SLCPs can provide health benefits:
(1) directly, it will reduce air pollution exposures and related diseases;
(2) indirectly, the negative effects that ozone and black carbon have on weather and food production, which affect food security, will be reduced;
(3) As a result of certain SLCP mitigation actions, such as improved transport systems, healthier diets, or better waste management, there other health benefits may also be obtained, such as improved chances for physical activity, less risk of traffic injury, reduced risks of diet-related chronic diseases, or reduced exposure to waste and sanitation-related health risks.
WHY SHOULD WE ACT NOW?
There is increasing evidence that direct exposure to certain SLCPs is associated with ill-health. As their name indicates, SLCPs have a short life-span in the atmosphere, which means that once emissions are reduced they disappear relatively quickly and health benefits begin to occur soon after and in some cases almost immediately.
Another important feature is that benefits will occur near where mitigation takes place, directly benefitting the health of communities. Therefore, controlling emissions of these SLCPs or their precursors could save lives through improved air quality, reduce expected warming by .5⁰C or more over the next few decades and contribute to food security.