NASA's Terra satellite acquired natural-color images of northeastern China on January 3 and January 14, highlighting a drastic shift in air quality for the region. According to the images, the opaque, gray areas tend to be clouds or fog, which are saturated with a gray or yellow tint as a result from the air pollution. Areas that are cloud-free appear gray and brown as a result from the smog that hides the cities below. Residual snow is also noted in the images.
NASA's Terra satellite acquired natural-color images of northeastern China on January 3 and January 14, highlighting a drastic shift in air quality for the region.
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According to the images, the opaque, gray areas are clouds or fog, which are saturated with a gray or yellow tint as a result from the air pollution. Areas that are cloud-free appear gray and brown as a result from the smog that hides the cities below. Residual snow is also noted in the images.
At the time that the January 14 image was taken by satellite, sensors at the U.S. Embassy in Beijing reported PM2.5 measurements of 291 micrograms per cubic meter of air. This is over ten times the level of which the World Health Organization considers to be safe. PM2.5 is fine, airborne particulate matter that is about the width of one thirtieth of a human hair. This pollutant is considered dangerous because it is small enough to enter the passages of the human lungs and can aggravate heart and lung diseases. Most PM2.5 particles come from the burning of fossil fuels in vehicles and power plants. PM2.5 can also be released from wood fires and agricultural burning.
The air quality index (AQI) in Beijing at the time the second image was taken was 341 whereas an AQI above 300 is considered hazardous to all humans. For comparison, an AQI below 50 is considered good. On January 12, the AQI peaked at 775 which is off of the US EPA scale.
So what exactly can this air crisis be attributed to? Historically, air pollution around Beijing has greatly been influenced by coal-fired power stations. However, population growth along with increasing development is causing the nation to choke on it's own expansion. With thousands of new cars taking to the road, and pollution that is exacerbated by weather patterns and cold spells, air quality and human health are suffering.
As a result of the recent decline in air quality, residents of Beijing and many other cities in China were warned to stay inside this month as the nation faced one of the worst periods of air quality in history.
In an effort to curb short-term air pollution, the Chinese government has ordered factories to scale back emissions. Nonetheless, according to national news reports, hospitals are seeing spikes of more than 20 to 30 percent in patients complaining of respiratory issues.
Read more at NASA Earth Observatory.
Satellite image via NASA Earth Observatory.
