Fresh off its unexpected best month of air quality since 1998, Beijing plunged head first this week back into mashed potato air quality. Mashed potato (scientific term, I promise) air looks like this from the ground (taken around 4pm today):
and this from space (2/20 photo from NASA):
From a data perspective, mashed potato air means three consecutive days of MEP’s API above 200 (including a 2/20 peak of 333 – equivalent to a daily average PM10 concentration of 446 ug/m3), the US Embassy’s BeijingAir Twitter feed consistently reading “Hazardous” or “Beyond Index” (PM2.5 concentrations peaking above 500 ug/m3), and the China National Environmental Monitoring Center’s new hourly air quality data showing…well, no particulate matter data at all for at least the past 48 hours for most centrally-located stations. This is disheartening, because it’s extreme episodes like this during which people – especially at-risk populations – need that data the most. The Wanshouxiguan (万寿西官) station does have hourly PM10 data, which show a peak near 480 ug/m3 (graph below shows that station’s hourly PM10 data from 2/21 6pm to 2/23 6pm):
For context, remember that the WHO’s daily recommended PM10 limit is 50 ug/m3, while the annual limit is 20 ug/m3.
Unfortunately, I have no time this week to run additional data analysis or provide more lengthy commentary, though I would like to repeat my previous comment about the Beijing EPB’s claims of credit for January’s excellent air quality: “If January’s good air quality was ‘far from a one-off,’ does this mean we can expect this much improved air quality to continue? (If it doesn’t, then I will be very curious to see what explanation is offered (if any) when the air pollution levels go back up to more expected levels for this time of year.)” The Beijing EPB issues monthly air quality summaries on the last day of each month, so let’s see what they say next Monday.
Lastly, just one criticism of the AFP story that’s going around:
BEIJING — Thick smog blanketing Beijing went “beyond” measurable pollution levels on Monday, the US embassy said, as a Chinese official warned people to stay indoors and avoid outdoor activities.
Actually, the pollution levels are still measurable, and reported. You can still see the pollution level, as highlighted here (in this case, a PM2.5 concentration of 515.0 ug/m3):
“Beyond index” doesn’t mean the pollution can’t be measured, it just means that the pollution level is beyond the US’ standard system for categorizing, which maxes out at 500. (Though we all know what it’s really called.)