Photos: Seattle can't dodge fog, but does escape air quality issues
Despite the week-plus of fog and stagnant air, the greater Puget Sound region has managed to dodge a burn ban and air quality advisories as so far, air quality has maintained at good to moderate levels through the period.
In measuring air quality, anything under 50 on the Air Quality Index (AQI) is considered good and 50-100 is moderate. Seattle has peaked around 65-75 in the period and has spent a good chunk of time under 50.
How have we managed that? Luckily, it hasn't been too cold overnight.
The mild overnight temperatures -- only dropping into the mid-upper 40s -- have helped curtail wood burning and prevented us from reaching levels unhealthy for sensitive groups in many areas in our region up to this point, says Erik Saganic, Puget Sound Clean Air Agency meteorologist. So pat yourselves on the back for not burning wood stoves and needing a burn ban!
What's up with China? I hear they're having terrible smog problems?
Even though we've leaned into the moderate category this week, our air quality issues are peanuts compared to what has been happening in China.
Winter typically brings the worst air pollution to northern China because of a combination of stagnant weather conditions and an increase in the burning of coal for homes and municipal heating systems, which usually starts on a specific date.
For the large northern city of Harbin, the city's heating systems kicked in on Sunday, and on Monday visibility there was less than 50 meters, according to state media.
"I couldn't see anything outside the window of my apartment, and I thought it was snowing," Wu Kai, 33, a housewife and mother of a baby boy, said in a telephone interview with the Associated Press from Harbin. "Then I realized it wasn't snow. I have not seen the sun for a long time."
She said her husband went to work in a mask, that he could barely see a few meters (yards) ahead of him and that his usual bus had stopped running.
"It's scary, too dangerous. How could people drive or walk on such a day?"
The density of fine particulate matter, PM2.5, used as an indicator of air quality was well above 600 micrograms per cubic meter - including several readings of exactly 1,000 - for several monitoring stations in Harbin, according to figures posted on the website of China's environmental protection agency. They were the first known readings of 1,000 since China began releasing figures on PM2.5 in January 2012, and it was not immediately clear if the devices used for monitoring could give readings higher than that.
To compare, Seattle has peaked around 25 to 35 on the PM2.5 scale this past week.
Is this persistent Seattle fog a record?
Wednesday marked the 6th day in a row with dense fog at Sea-Tac Airport, nearing at least an entry in the Top 5 of record books for consecutive days with dense fog. The record is 13 days in a row in Dec. 16-28 in 1985:
Most consecutive days with dense fog (1/4 mile visibility or less):
1) 13 -- Dec. 16-28, 1985
2) 10 -- Dec. 30, 1980 - Jan. 8, 1981
3) 9 -- Jan. 3-11, 1985
4) 8 -- Oct. 16-23, 1955
5) 7 -- 6-way tie, most recent: Jan. 16-22, 2013
11) 6 -- Oct. 18-23, 2013* -- Current (tied with several other years)
How about dry streaks? Wednesday marks the 11th day in a row with no rain in October. Turns out, long October dry streaks are not that uncommon.
Most consecutive days without rain in October:
1) 23 -- 1986
2) 19 -- 1978
2) 19 -- 1952
4) 15 -- 1991
5) 13 -- 1987
While this year has pretty decent odds we'll finish the month dry, since our streak began on Oct. 13, we can't even reach the record this year.
Once we get into November, streak counting gets tricky. If the October streak is still current at 19 days once we reach Nov. 1, the streak has to register into the overall annual dry streak record to count in the record books-- which is 51 days. So, no way we'll reach that (we hope?)
There are records kept for "rainy season" dry streaks but that doesn't start until Nov. 1, so the 19 days we'd have prior to that would not factor into that record. In other words, if it didn't rain until Nov. 6, our rainy season dry streak for 2013 would be considered 5 days, not 24.
How about driest Octobers? Not this year. The convergence zone rains earlier in the month already have October's tally at 1.44 inches -- 11th driest (driest is 0.31" in 1987). So even if we go blank the rest of the month, it's not record-dry. Same for fewest days with rain: We already have 9 and 3 is the record with a number of years at 4, 7, and 8 days of October rain.
So really the only record we're chasing is days with dense fog, but it appears to be in reach! Something to root for besides seeing the sun again some day...
Associated Press writer Louise Watt contributed information on the China air pollution.