La Guardia Airport Weather Station
New York City Region - August 1999
Haze/Ozone and Encephalitis
La Guardia is about 3,000 feet west of College Point, part of the the epidemic epicenter. Most departures fly southwest of this area. S, SSW, SSE winds can blow exhaust from aircraft within the mixing height (up to at least 3,000 feet) into the epidemic area.
Ground ozone levels usually correlate with temperature.
Hospital entries of WNV victims, as gleaned from the media, are color-coded with light blue. August 5th (stated August 4th in latest reports) was the first seropositive WNV human of the epidemic.
First substantial rain of the summer was 8/14/99. Previous substantial rain was 5/24/99. So the "mosquito-free summer", touted in the The New York Times on 8/7/99, was still in effect, since it takes 10-14 days for larvae to mature. There was 0.29 inch rain on 8/4/99, but that would evaporate easily at the daily temperatures of 89, 90, 87 following, where the wet bulb temperature was relatively low (indicating high evaporation rates).
Weather Chart Legend HZ Haze (can be smog) RA Rain TS Thunderstorm FG Fog WresSpd Wind, Resultant Speed (given number times 10) WresDir Wind, Resultant Direction Prec Precipitation
Compare with two charts of ozone levels at College Point.