Se ha denunciado esta presentación.
Utilizamos tu perfil de LinkedIn y tus datos de actividad para personalizar los anuncios y mostrarte publicidad más relevante. Puedes cambiar tus preferencias de publicidad en cualquier momento.

040704 July4 Haze

821 visualizaciones

Publicado el

  • Sé el primero en comentar

  • Sé el primero en recomendar esto

040704 July4 Haze

  1. 1. FASTNET Event Report: 040705July4Haze, July 6, 2004 July 4, 2004 Aerosol Pulse Event Summary by the FASTNET Community Please send PPT slides or comments to Erin Robinson or Rudy Husar, CAPITA Visit the event discussion forum
  2. 2. Background • During the US Independence day celebrations on July 4th, fireworks cause the emission of considerable smoke in most populated areas • While it is a sort-term aerosol event, the fireworks smoke has a measurable impact on the local aerosol pattern • Earlier analyses of IMPROVE aerosol chemistry data have shown that fireworks smoke has a strong signature, rich in potassium (Poirot, 1998) • The FASTNET data shown here also demonstrates that the fireworks cause a strong short-term pulse of the PM2.5 concentration in most urban areas. • A community analysis activity could quantify the magnitude, significance and relevance of this phenomenon.
  3. 3. Previous work: The July 4th Potassium Spike (Poirot 1998) • Potassium nitrate is a major component of all fireworks (provides the bang!). • Fine particle K for all IMPROVE data (1988-1997) were averaged for each day of year • The potassium spike on July 5 is 120 ng/m3 compared to 40-60 during the year • The corresponding IMPROVE-average daily fine mass did not show the spike • The K spike is clearly something to consider (and perhaps screen out) in conducting any analyses using K data
  4. 4. FASTNET Analysis: AIRNOW PM25 Hourly data • Hourly PM25 concentrations are averaged over all the AIRNOW sites (~300) • Late on July 4 and early July 5, the average PM2.5 increased from 12 to 35 ug/m3 • An aerosol pulse of the same magnitude occurred on July 4, 2003 • Thus, the July 4-5 smoke pulse is clearly discernable in the mass concentration data
  5. 5. AIRNOW PM25 Maps, July 4, 5, 2004 12:00 00:00 16:00 04:00 20:00 08:00 AIRNOW PM25 mass concentration shows urban hot-spots The aerosol pulse first appeared in the East and subsequently in the West See the GIF animation for the hourly pattern
  6. 6. ASOS Light Scattering • Hourly ASOS scattering is averaged over all the ASOS_STI sites (~200) • Conspicuous is the absence of ANY trace of the July 4 spike • Note: ASOS sites are at airports; many AIRNOW sites are downtown
  7. 7. Discussion Issues • Why is the PM25 mass spike so strong in AIRNOW but not in the IMPROVE data? • Is the fireworks smoke significant on regional scale? • How to handle the July 4th data in the source apportionment models (UNMIX, PMF) • Is the PM25 and potassium pulse useful for further tracer analysis?
  8. 8. July 4, 2004 Aerosol Pulse • The US-avg. AIRNOW PM25 shows a 3 hr. spike at midnight • In the (airport) ASOS the July 4 spike is conspicuously absent AIRNOW PM25 • Thus, the US spike is due to the urban sites affected by smoke 20:00 AIRNOW PM25 Pulse US Hourly Average 00:00 ASOS Bext No Pulse 04:00 US Hourly Average 08:00