Tiny particles make seasonal appearance
The cooler, calmer weather signals the start of the Valley's next air pollution concern: tiny bits of soot, dust and chemicals. In warmer weather, the problem is ozone, the main ingredient in smog.
The San Joaquin Valley violated the federal standard the first for days of November, but the air has been better for the last week.
Pay attention to the local air district's daily forecasts to find out if it's legal for you to burn wood in your fireplace or wood stove. There already have been several wood-burning bans.
The tiny pollution specks, as you may recall, are quite dangerous. They pass through the body's defenses and get into the lungs.
Such particles have been connected with lung and heart disease as well as early death.
The early morning hours are generally fine for vigorous, outdoor exercise, local air district experts say. But there's a buildup of particles in the later morning and early afternoon. By late afternoon, the particle levels begin to drop.
Comments:
Interesting how the best air this time of year is during the two or three hours right after sunrise and then, again, during the last couple hours of daylight. It is generally the worst around midnight but the particulates peak again around noon. Any explanation for this cycle? Maybe it is November only that does this when the days are still relatively warm.
Posted by: airqualityguy at November 10, 2009 9:54 PM
The pattern of high PM 2.5’s is consistent with fireplace use, there really is no other explanation for high PM at midnight. When I come out of a late movie in Clovis the stench of wood-smoke is pronounced, whether there is a burn ban or not. (You can sometimes smell it even in the theatre) Of course no one is ever cited for burning at night. There are no inspectors after dark, they only inspect during banking hours when (surprise) most people are at work.
Many people light a fire early in the morning before going to work. (This I observe in my own neighborhood) Retirees, who might tend to sleep in a bit, start theirs later. The accumulation of all those fires, as well as the morning traffic, causes the mid day spike. Says me.
Alternately, maybe it’s the ghost of Archie Crippen.
It’s pretty rotten that the soot level has to be twice the federal clean air standard before a ‘no burn’ is called. By my count, there have been 4 days already this November when the average reached or exceeded the 30mcg per cubic meter threshold but were burn days anyway. Guess it’s not an easy job to forecast how bad the air will be tomorrow, but if the air district allows 29.9mcg/m2 as an acceptable daily average and says ‘go ahead and burn “cleanly”’, how will we ever get to a yearly average of 15?
Pray for wind.
As I write this, the soot levels are rising and it looks like Fresno will exceed the 30mcg average. All that clean burning.
Posted by: fumed at November 17, 2009 9:56 PM
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