FASTNET Event Report: 040705July4Haze, July 6, 2004

July 4, 2004 Aerosol Pulse

Event Summary by the FASTNET CommunityPlease send PPT slides or comments to Erin Robinson or Rudy Husar, CAPITA

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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.

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

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

AIRNOW PM25 Maps, July 4, 5, 2004

12:00 00:00

04:0016:00

08:00AIRNOW 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

20:00

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

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?

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

• Thus, the US spike is due to the urban sites affected by smoke

00:00

04:00

08:00

20:00

AIRNOW PM25

AIRNOW PM25

US Hourly Average

ASOS Bext

US Hourly Average

Pulse

No Pulse