Haze, Warm Mornings and UVB

Cleaning Up Our Atmosphere

The industrial revolution has long been blamed for as many things as the every-several-years El Niño was in the 1980s.  CED thought it might be interesting to look into the climate changes during the time of taller smoke stacks, child labor and wealth generation.

In terms of air pollution and combustion for the human good, history shows a trend toward cleaner and cleaner energy production: wood, peat, brown coal, soft coal, hard coal, fuel oil, natural gas, and PI (i.e. politically incorrect) Nuclear and the hasn't-happened-yet hydrogen fusion. 

From the Bulletin of the American Meteorological Society [1948, Vol. 11, p. 14] we have a little piece on New York City, the Big Apple, and the transition from soft coal to hard coal during the early years of the 20th century.

Rather than using modern PC terminology, such as pre-Robber Baron days, the Bulletin looked at the pre- and post-soft coal days in the Big Apple.  Soft coal via soot, fly ash and hydrocarbon production may well have prevented outgoing radiation and kept warmth in, according to the Bulletin. 

Here is the data. Soft coal era = 1911-1915 and Post-soft coal era = 1928-1932.  Minimum Temperatures in (F).  Winter = Dec. 1 to March 1.




























In pre-soft coal times there was little difference from day-to-day and weekday-to-weekend in minimum temperatures.  In the dirty post-soft coal days, workweek mornings were on average 3.6 F warmer than weekend day off mornings.  The would-be commuter could look skyward at the pall and say at least it cuts his heating bills.

The bulletin then mused on this voodoo economics.  "... it would be interesting to speculate on the economic value of the smoke cloud, on how many tons of coal in furnaces are saved by a ton suspended in the air."  Now talk about politically incorrect science!  Sometimes we forget how dirty our air once was and how far we have come.

Now some up-to-date stuff.

Urban air pollution has long been known to result in a reduction of UVB at street level.  Liu in the Journal of Geophysical Research Letters December 1991, made estimates for New York City today compared to pre-industrial times in the Big Apple.  New Yorkers get 20 to 30% less UVB than those poor, wretched louts of pre-Robber Baron times.  Sun Protection Factor #15 cuts UVB penetration in to the skin by 66%!  Maybe they ought to call the Big Apple's Gothic gray sky ozone hole sunscreen.

Liu also notes that haze in rural areas, which he assumed to be man-made, reduces UVB 5 to 18%.  The hydrocarbons, which make haze in rural areas, come, for the most part, from vegetation (90%) and a lesser part from human sources (10%). 

In spite of the reductions in ozone of some 3% since 1969, UVB levels at the ground have gone down, not up.  Haze?  Perhaps some?  What else?  Clouds!  Evidence indicates that cloudiness over Northern Hemisphere lands has increased dramatically this century and there is also evidence of increases in clouds over the oceans as well.  (Are there ecosystem consequences for the observed 17% increase in cloud cover for North America this century?  Inquiring minds want to know, or is temperature the only variable of climate change with merit?)  Clouds are, next to a good baseball cap, great UVB blockers.  All of this begs the question regarding the cause of the INCREASE in stratospheric ozone between the mid 1950s and 1969.  Ozone in the stratosphere may go through natural as well as person kind caused variations: 6% up then 3% down (Elsasser, 1979).

If we just look at clear sky days (1975-1990) [see the Smithsonian's David L. Correll and a long list of friends in J. Geophy. Res. Vol 97(D7):7579-7591] UVB at the surface in Washington DC has increased in the 1980s, perhaps due to less stratospheric ozone.  So cloudy days and the trend in this century toward more cloudiness is implicated in our reduced UVB load at the surface and the increasing difficulty in getting a tan.  Cut back your use of your UVB blocker to sunscreen #14!  Correll, however attributes the variation in UVB at the surface to ozone variations modulated by the solar sunspot cycle, not to CFCs at all.  Oh, if in our world causality was always an univariate one [Time magazine level stuff], how easy our scientific life would be.

The old Bulletin of the American Meteorological Society article goes on:  "Clean air with its full value of health-giving ultraviolet light must be furnished to all the people just as clean milk and water are now available, insisted Dr. Fred O. Tonney of the Chicago Health Department, in his address before the American Public Health Association in Washington D.C.." Tonney also suggested that supplying clean air might become a "function of government!"  Those guys were ahead of their time or could see the future clearly through the pall of the robber barons' detritus.


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