The air quality in Beijing the past two weeks has been excellent. Blue skies, striking sunsets and US EPA Air Quality Index ratings as low as 9, have been enjoyed by Beijingers since August 20th, when government sanctioned clean air measures went into effect.

The air has been so clean, in fact, it’s gotten the attention of the Air Visual team and sent us wondering - when was the last time Beijing had this long a stretch of clean air?

Using our comprehensive database to crunch historical data points for the past seven years, we were able to come to some truly incredible findings.

Not only were the past two weeks the best Beijing has seen in almost a decade, according to our databases, the air was twice as good, in regards to PM 2.5 concentration, as any other two week period in the past seven years.

In Depth - Arriving at our Findings

Digging deep into our historical database we managed to pull recordings of PM 2.5 concentration and AQI scores for the previous seven years.

We divided each year into groups consisting of two week increments. We then took each of these increments and ran statistical analyses to determine which group contained the lowest averages.

The findings of these tests proved that the period spanning August 21st, 2015 to September 3rd, 2015, the two weeks leading up to the military parade, were indeed the lowest on record - with an incredible average PM 2.5 concentration of 17 µg/m3, almost half the concentration of the next lowest reading from 2011.

Table 1.1 shows both the average AQI and PM 2.5 concentration for the 6 lowest recorded data sets and a comparison against the "APEC blue" week and the Olympic Games period. Three sets notably coincide with international events receiving government sanctioned clean air.

The findings prove that the two week period before the military parade was not only the best in terms of PM2.5 concentration and AQI, it was more than three times clearer than the air during the Olympics and APEC conference periods.

Table 1.1. The 6 lowest average PM 2.5 concentration and AQI readings for Beijing since the start of 2008.

The above information conveys Beijing does have a short term solution to air pollution – which is clearly demonstrated when tasked with hosting international events, hence the terms “APEC Blue” and “Parade Blue.” Unfortunately, economic goals often outweigh environmental targets.

Though the situation is improving, excellent air quality is still the exception in Beijing, and not the norm - which has us wondering, how long will it take until the public can name the blue skies once more?

** Historical data will soon be available for download on our website. In the meantime, please contact us if you would like to acquire this data today.