Getting countries to reduce greenhouse gases causing global warming is proving to be a difficult task.
But persuading them to clean their air for public health was easier ̵
They say that international efforts to reduce air pollution show some promise in terms of gas warming.
The global effort to tackle emissions will be discussed on Monday at the UN Climate Summit in New York.
The Climate and Clean Air Coalition was formed by six countries.
The United Nations Environment Program (Unep) also participates in the coalition, which was formed in 2012 and today lists more than 100 governments as members.
"We have seen countries join this initiative because it is an immediate public health issue," says Zhang Liu, Air Pollution e xpert with Unep, who heads the coalition.
"And there are mutual benefits: air quality and climate."
So, can we really handle both problems with one effort?
While some of the gases mark both boxes, others are air pollutants with no warming effect and vice versa.
Focus on CO2
When scientists talk about reducing greenhouse gases, which are responsible for warming the planet, they focus mainly on carbon dioxide (CO2).
This is because it accounts for nearly two-thirds of the emissions and can remain in the atmosphere for thousands of years.
Last year, it reached 411 ppm (ppm) at the Mauna Loa Loa Atmosphere Base of Hawaii's Observatory, the highest monthly average ever recorded.
Some experts say 350ppm is the safe limit, while others say 400ppm should be a reasonable target.
Combustion of fossil fuels, wood and solid waste results in CO2 emissions. Some industrial processes and changes in land use, including deforestation, also lead to emissions of this major greenhouse gas.
But since the global economy is still largely fossil fuel-based, energy policy is a major impediment to progress in reducing CO2 emissions to combat climate change.
But scientists say there are other gases that pollute the air and also warm the planet.
Black carbon and methane are air pollutants, which are also responsible for 30-40% of global warming, according to atmospheric scientists at Unep.
The sectors that produce the vast majority of greenhouse gases – energy, transport, industry, agriculture, waste management and land use – are also the main sources of these air pollutants.
Thus, limiting their emissions, experts say, will help for the health of humans and also for the health of the planet.
They are also known as short-term climate pollutants (SCLP).
"Rapid action to reduce SCLP emissions will immediately gain human health and slow down the rate of short-term warming – the benefits that will be felt most in regions where emissions are reduced," according to a recent World Health Report
SLCP emissions could reduce warming by up to 0.6C by 2050, he adds, avoiding 2.4 million premature deaths from atmospheric air pollution by 2030
] The UN Health Agency estimates that the pollution of indoor and outdoor air contributes to about seven million premature deaths worldwide
More than four million of these deaths are caused by outdoor air pollution
Common air pollutants
One of the most The most common outdoor air pollutant is particulate matter, which is divided into categories known as PM1, PM2.5, and PM10, based on
respiratory infections, heart disease, lung cancer, and even brain development. PM2.5.
These are fine particles measuring one-third the diameter of human hair that can reach the lungs.
While particles are considered to be an air pollutant, one of its components – black carbon – is a short-term climate pollutant.
Its deposition on snowfields is also accused of absorbing sunlight and accelerating melting.
There are currently no national or international regulatory obligations to monitor, measure or report black carbon emissions, say WHO officials.
Another invisible combination of pollutants is ground-level ozone, which comes from traffic , agriculture and other sources.
One of the precursors of ozone is nitric oxide, which comes from the burning of fossil fuels. This is pleasing to bronchitis in asthmatic children, reducing their lung function.
But it is also a greenhouse gas.
For more information on the UK's efforts to tackle CO2 emissions, download BBC Briefing on energy. Part of a mini-series of guides for downloading the main topics in the news, it has been contributed by scientists, researchers and journalists and is the BBC's response to requests for a better explanation of the facts behind the headlines.
"The theory that reducing air pollution will help reduce some of the greenhouse gas emissions that cause climate change is pretty stable," says Leslie Ott, an atmospheric scientist at Nasa.
"So, for example, if you can make your power plants less polluting, you reduce greenhouse gas emissions and reduce air pollution.
" But you still have to deal with the problem of reducing emissions CO2 because it is the main greenhouse gas we emit and it stays in the atmosphere for a long time. "
Experts say the Paris Climate Agreement does not require countries to report on their steps to reduce SLCP.
Under the agreement, which aims to keep global heat g far below two degrees compared to pre-industrial times, countries are required to report on their actions to mitigate climate change.
It is a legal non-binding requirement.
"The likely achievement of the objectives of the Paris Agreement is impossible without reducing the emissions of SLCP," says Jian Liu, an air pollution expert with Unep.
Although UN officials are pleased that countries support the reduction of air pollutants, which can also reduce greenhouse gas emissions, they acknowledge the lack of reporting and monitoring remains a great challenge.
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