Air pollution is killing millions of people every year, making it a global public health concern.

Research released on Feb. 12 suggests that over 5.5 million people die every year as a result of breathing in too much polluted air.

Michael Brauer, a professor at the University of British Columbia’s School of Population and Public Health in Vancouver, Canada, told CBS News, “Air pollution is a major global health issue that is probably something that many people experience, but that is not as well-recognized by the health sector in general.”

The countries with the highest number of deaths are China and India, with 1.6 million and 1.3 million pollution-related deaths each year, respectively. Both countries have rapidly growing economies.

Most of the pollution is the small particles that power plants, factories, vehicle exhaust and burning coal and wood produce. Inhaling tiny liquid or solid particles can increase a person’s risk for heart disease, stroke, respiratory complaints and cancer.

Dan Greenbaum from the Health Effects Institute in Boston, Mass., explained to BBC News how much some countries will need to do to improve their citizens’ air quality.

“In Beijing or Delhi on a bad air pollution day, the number of fine particles (known as PM2.5) can be higher than 300 micrograms per cubic meter. That number should be about 25 or 35 micrograms.”

In China, most of the particle emissions come from coal burning, a source that this project calculates is responsible for 360,000 yearly deaths. With an aging population, China expects to struggle to bring that number down.

In India, the problem is from indoor pollution: people burning things like wood, dung and crop residues for cooking and heating. This indoor pollution allows for more direct contact between people and the harmful particles, leading to more deaths than those caused by outdoor pollution.

As these economies expand and standards of living rise, curbing emissions will only become more challenging.

India is already experiencing this tension.

“Despite proposed emissions control, there is significant growth in the demand for electricity as well as industrial production,” Chandra Venkataraman, from Mumbai’s Indian Institute of Technology Bombay, told BBC News. “So, through to 2050, this growth overshadows the emissions controls (in our projections) and will lead to an increase in future air pollutant emissions in 2050 in India.”

Brauer hopes China, India and other pollution heavy countries will solve their air pollution woes before then.

“The trick here is to not take the 50 or 60 years that it took in the high-income countries, and to really accelerate the process — and that’s really where we think these statistics, the data, will come in handy,” he told BBC News.

It seems possible that China and India will successfully address this issue. This study has come out only months after the Paris climate talks, where 188 countries (including China and India) agreed to cut carbon emissions. And although it took them decades to do so, many high-income countries managed to improve air quality as their economy has grown.

Reducing air pollution could save countries millions of dollars in health related expenses as well. Brauer estimates that for every dollar the United States spends on lessening, it saves between $4 and $30 on reduced health impacts.

With this knowledge, decreasing air pollution is beneficial to all.

“Everybody breathes the air and everybody benefits,” Brauer told CBS News. “Cutting back on air pollution is an efficient way to improve the health of the whole population.”