The "airpocalypse" in China has become so severe in recent years, with outdoor air pollution levels 25 times higher than what is deemed safe in the United States, that its annual death toll is over one million.

A new summary of Chinese data from the massive 2010 Global Burden of Disease Study, which was published last December by the medical journal The Lancet, calculated a whopping 1.2 million premature deaths related to outdoor air pollution in the year 2010 alone, reported the New York Times.

The researchers calculated that "ambient particulate matter pollution" was the fourth-leading risk factor for deaths in China in 2010, and ranked seventh on the list of worldwide risk factors. According to their figures, outdoor air pollution led to 3.2 million deaths worldwide that year.

The public health threat of the "airpocalypse" in China has grown even worse in the past three years- in January 2013, outdoor air pollution skyrocketed to record heights in northern cities like Beijing. The New York Times reported widespread outrage in the Chinese media, and the notoriously restrictive government finally began releasing hourly pollution readings for 74 Chinese cities earlier this year.

Such a dramatic increase in outdoor air pollution indicates that premature death counts for the years after 2010 are likely to rise even higher. According to the NY Times, a 2007 report sponsored by the World Bank estimated that up to 400,000 people die from air pollution in China each year- only a third of the 2010 death toll.

It seems unclear how effectively the Chinese government is responding to the nation's airpocalypse. NPR reports that the city of Beijing has vowed to cut air pollution by 15 percent over the next three years- a paltry figure compared to the growing use of coal among factories in surrounding provinces.

The Organization for Economic Cooperation and Development expects that "urban air pollution is set to become the top environmental cause of mortality worldwide by 2050, ahead of dirty water and lack of sanitation."

Worldwide outdoor air pollution deaths are concentrated mostly in Asia, where China and India represent much of the world's growth in population, infrastructure, and energy consumption. An "airpocalypse" is no longer such a severe threat in the United States- a recent study announced that American air pollution deaths are projected to drop to about 36,000 in 2016.

According to the United States Environmental Protection Agency (EPA), outdoor air pollution, primarily from excess ozone in the air, "can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ground level ozone also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue."

Illnesses and deaths from exposure to severe outdoor air pollution are more likely in certain subsets of the population.

"For the most part, the air pollution effects are generally manifested in frail populations - people with asthma are generally more susceptible to the effects of air pollution," study researcher Robert O'Keefe of the Health Effects Institute in Boston told NPR. "Also the very young and children who live in highly polluted areas for extended periods of time."