# Presentation: 582775

## AEROSOL MASS SPECTROMETER MEASUREMENTS ON BOARD THE G1 AIRCRAFT DURING THE NEW ENGLAND AIR QUALITY STUDY 2002/2004

- John Jayne, Tim Onasch, Manjula Canagaratna, Scott Herndon
- Doug Worsnop
- Aerodyne Research, Inc.
- Mike Alexander, Alex Laskin, Tom Jobson, John Hubbe
- Pacific Northwest National Laboratory
- Peter Daum, Larry Kleinman, Stephen Springston
- Brookhaven National Lab

**Notes:**
Name, ARI, title, John Jayne and Alex Laskin, PI’s.

## NEAQS Campaigns Improve understanding of sources, production and transport of pollutants in NE area

- Gulfstream 1 (G1) participation
- Worcester, MA.
- July 1-Aug 11, 2002
- 		Worcester regional airport
- Latrobe, PA.
- 		July 25 – Aug 14, 2004
- 		Arnold Palmer regional airport

## AMS Deployment on the G1 Aircraft 

- AMS Deployment on the G1 Aircraft

*AMS Package*

*Double Diffuser Cone Gas/Aerosol Inlet System - Fred Brechtel*

**Notes:**
Rack mounted ~190 kg and 600 Watts.  Utilized the double diffuser cone inlet system designed and built by Fred Brechtel with great success.  The AMS samples aerosol into a vacuum, determines the vacuum aerodynamic diameter via TOF measurements, and utilizes a quadrupole MS for detection.

## Real Time Chemical and Physical Composition of Aerosols

**Real Time Chemical and Physical Composition of Aerosols**

- Aerosol Sampling

*Sampling frequency 30 sec.*
*~3 km spatial resolution*

**Mass distribution**

**Chemical composition**

**Nitrate**
**Sulfate**
**Ammonium       ****Alkanes**
**Organics            ****Aromatics**
**	****             ****Etc**..

**   ****AMS**

**Notes:**
I am going to skip the details of how the AMS works, please feel free to find me and ask questions afterwards if interested.  
The two main types of information that can be derived from the AMS are mass distributions (TOF measurements) and chemical compositions (mass spectrometry).
30 second integrations:  3 km horizontal resolution and 125 m vertical resolution.  Accumulation mode in urban setting.  Small mode organic from traffic and corresponding long chained HC MS.

## NEAQS 2002:  Worcester, MA

- 17 research flights, 3-4 hr duration

**Notes:**
Main objective of the experiment was to characterize the outflow of particles from the NE continental US.  Here a few of the flights made that cover the NE region.  There are four other sites (Whiteface Mnt., Harvard Forest, Boston College, and the Ron Brown) with particle/gas instruments.  Aircraft enables altitude profiles.  Discuss two flights in specific.

17 flights + 2 test flights + 4 ground experiments

## NEAQS 2002:  Sulfate Plume

- July 22, 2002

**Notes:**
Main objective of the experiment was to characterize the outflow of particles from the NE continental US.  Here a few of the flights made that cover the NE region.  There are four other sites (Whiteface Mnt., Harvard Forest, Boston College, and the Ron Brown) with particle/gas instruments.  Aircraft enables altitude profiles.  Discuss two flights in specific.

17 flights + 2 test flights + 4 ground experiments

## Vertical Profile over 

**Vertical Profile over **
**the NOAA Ship *****Ron Brown***
- Flight Track on July 22, 2002

- Ron Brown

- Ron Brown

**Notes:**
July 22nd flight was designated to flying a vertical profile over the Ron Brown, situated off the coast of New Hampshire.  There is definite structure in the mass loadings for this flight.  Here again, the organics and sulfate dominate, with several large plumes of sulfate dominated aerosol.  The G1 passed the Ron Brown at low altitude before and after the vertical profile, with results similar to Ann Middlebrooks results for the same time from an AMS located on the Ron Brown.  The G1 then flew up, did a dog leg, flew up, did a dog leg, etc. up to 10000 ft, passing through several sulfate plumes.  I will now focus in on the vertical profile segment.

## G1 Flight Track

- Latitude (deg.)

- Longitude (deg.)

- Altitude (ft)

- NOAA Ship
- R.H. Brown

*Horizontal Transects over NOAA Ron Brown*

- July 22, 2002

*Air masses are “layered”*

**Notes:**
The vertical profile illustrates the layered ‘nature’ of the atmosphere above the Ron Brown on July 22nd.  This profile suggests that the upper air masses were advected horizontally above the Ron Brown, and the thus were not likely emissions from local NH/Mass sources.

## What Is the Origin of the Sulfate Plume?

*Back trajectory shows high sulfate air mass at 1.3 km originating from Ohio Valley*

*Back trajectory shows high SO**2** air mass at 0.5 km originating within New England Region*

*NOAA Hysplit model trajectories from July 22-20*

**Notes:**
Back trajectories from July 22nd, show that the upper air mass (1300 and 1700 m) may have passed through the Ohio River Valley.  The source of the sulfate plume may indeed be power plants in the midwest.  Note that the lower level air mass is shown to originate within the NE region, passing over Long Island and Boston.

## NEAQS 2004: Latrobe, PA 

*Arnold Palmer Region Airport, LBE*

## Flight Tracks: SO2 Emissions

**Notes:**
Main objective of the experiment was to characterize the outflow of particles from the NE continental US.  Here a few of the flights made that cover the NE region.  There are four other sites (Whiteface Mnt., Harvard Forest, Boston College, and the Ron Brown) with particle/gas instruments.  Aircraft enables altitude profiles.  Discuss two flights in specific.

17 flights + 2 test flights + 4 ground experiments

## PA area coal fired power plant

*PA area coal fired power plant*
* **as viewed from G1*

## NEAQS 2004 Plume Study - South Western PA

- Aug. 9, 2004

## Sulfate Plumes from two PA area Coal Fired Power Plants

## Forward trajectories show plumes being transported to New England Area

- Typical winds are S-SW

## Quick Summary

-  2002 measurements made in NE show sulfate plumes originating from Ohio Valley area
-  2004 measurements made in Ohio Valley Area show sources being transported to NE

*Lets look at the Chemical and Microphysical properties of the aerosol*

## Typical Aerosol Mass Spectrum 

- Typical Aerosol Mass Spectrum
*Latrobe, PA area*

*Electron impact ionization following flash vaporization at ~600C*

## Plume Study – PA

*Aerosol is Acidic in “Fresh” Plumes*

## SO2 – Sulfate plumes NEAQS 2002

- SO2 – Sulfate plumes NEAQS 2002

*“**Newer/less-processed”*

*“**Older/more-processed”*

**Notes:**
Have added SO2 data (black) and the sulfate size distributions.  The altitude curve is the same.  These results illustrate two different air masses.  The first, at low altitude, is strongly influenced by sharp (recent) SO2 plumes and lower, though still correlated, SO4 spikes.  As the G1 goes up in altitude, the SO4 mass loadings increase relative to the SO2 concentrations, and the SO2 becomes less ‘active’, signatures that the upper air mass is ‘older/more processed’ air.  This switch in SO2/SO4 ratio is similar to what was observed for July 14th , but here its more obvious.  The size distribution data is in agreement.  In the lower air mass, significant SO4 mass is observed at smaller sizes, whereas the higher air mass has sulfate mass only in the accumulation mode. 

Taking size distribution slices at two different times (SO2 spike in lower air mass, and in the upper air mass), its obvious that the lower air mass is bimodal, with a lot of SO4 mass in the small, growth mode.  This mode is evidence of particle nucleation that took place somewhere up wind of the G1 that started to grow, but has yet to reach the accumulation mode.  The upper air mass is all accumulation mode, with no evidence of mass in the smaller mode.  During several SO2 spikes, the AMS observed evidence for sulfate mass down to ~30 nm in diameter, indicating that the particles had very recently nucleated.  (Example, 1:30PM).   

## The organic component of the aerosol mass spectrum

- NEAQS 2004, PA

## The organic component of the aerosol mass spectrum

- NEAQS 2004, PA

## Typical terrain in western PA area study  

- Typical terrain in western PA area study

*Significant biogenic emissions...SOA *

## Ratio of m/z 44 to total organic is a measure of the degree of oxidation  

- Ratio of m/z 44 to total organic is a measure of the degree of oxidation

## NEAQS 2002 – New Jersey flight track

*Urban / Industrialized Area*

## Observations of Primary Organic Particles

*Traffic Emissions*

-  Evidence of primary organic particles in small particle mode.
-  Small mode typical of primary traffic exhaust emissions

## Summary

-  Ohio Valley Area appears to be a significant source of sulfate for the New England area.
*High levels of sulfate observed as direct emission from PA area coal fired power plants.*
-  In rural PA area organic aerosol is highly oxidized.
* **SOA (biogenic sources).*
-  In NY/NJ area a measurable fraction of the organic aerosol is primary emitted HC (consistent with vehicle traffic) which adds to the oxidized organic aerosol background.

## Acknowledgements

_**PNNL Team**_
*John Hubbe*
*Carl Berkowitz*
*Alex laskin*
*Victor Morris*
*John Schmelzer*
*Larry Berg*
*Rich Barchet*

_**Pilot**_
* **Bob Hannigan*

_**BNL Team**_
*Larry Klineman*
*Yi-Nan Lee*
*Xiao-Ying Yu*
*Steven Springston*
*Gunnar Sennum*
*Jain Wang*

***Funding***
*DOE ACP*
*DOE SBIR*
*NSF STTR*
*ONR SBIR*

## END

## Organic component of aerosols

-  Highly oxidized organic components
-  No significant stratification of the oxidation “age” of the organics.

**Notes:**
The mass spectra clearly show the sulfate and ammonium fragments standing out above the organic signals.  A look at the total organic aerosol fraction shows fairly short chained organic species that are highly oxidized.  The largest peaks being m/z 44 and the associated 18 due to decarboxylation of acids at the vaporizer temperatures.  m/z 44 is currently our best marker for the particulate C:O ratio.  A scatter plot shows a strong linear relationship for the whole flight with a slope of ~0.15.  Slopes indicated are our markers for “fully oxidized”, “partially oxidized”, and primary organic particles.  Colored here by time, there is no strong relationship to altitude, flight track position, etc.  

## Slide 30

## Organic NEAQS 2004 Aug. 9, 2004

## Measurable Mass at 8000 ft

## Slide 33

## Slide 34

## Slide 35

## Slide 36

## Northeastern Corridor Emissions profile:

**Northeastern Corridor Emissions profile:**
**Power plant and city sources.**
- Flight Track on July 16

*Power Plant Emissions?*

*Traffic Emissions?*

**Notes:**
This flight’s objective was to sample the emissions from power plants and cities along the NE corridor.  

## Aerosol Mass Spectrometer (AMS)

**Particle Inlet (1 atm)**

**100% transmission (40-600 nm), aerodynamic sizing, linear mass signal.**
- Development of an Aerosol Mass Spectrometer for Size and Composition Analysis of Submicron Particles.
*Jayne et al., Aerosol Science and Technology 33:1-2(49-70), 2000.*

**Quadrupole**
**Mass Spectrometer**

**Thermal Vaporization &**
**Electron Impact Ionization**

**Aerodynamic Lens**
**(2 Torr)**

**Chopper**

**Pump**

**Pump**

**Pump**

**TOF Region**

- Particle Beam

- Generation

- Aerodynamic Sizing

- Particle

- Composition

**Notes:**
Introduction to our instrument and the type of information that it generates.  Three sections:  sampling, TOF, and particle composition.

## Constant altitude profile:

**Down wind/up wind of coastal sources.**
- Flight Track on July 14

-  Aerosol composition is dominated by sulfates and organics

**Notes:**
The first flight was a constant altitude profile down wind/up wind of costal sources.  Two main legs to focus on are the yellow (out over the cost) and blue (inland, upstate NY).  The AMS show a fairly constant aerosol mass loading through the flight, with a drop during the high altitude excursion. Flying down wind to up wind of coastal sources, we are looking for signatures of local (North Eastern) and/or transported source contributions to aerosol. Relatively high mass loadings (3000 ft – 1000 m), in what appears to be a large area event.  Same flight plan two days earlier observed much lower aerosol mass loadings!

## Chemically-resolved size distributions

-  Apparent internally mixed accumulation mode aerosol particles.

**Notes:**
An image plot illustrates the sulfate size distribution for the entire flight.  Left axis Dva, bottom axis is time.  The colors indicate the mass loadings at a given size.  Integrated, the full size distributions shown on RHS show internally mixed accumulation mode particles.  Typical results for ‘processed’ or ‘aged’ particles.  There might be a hint of sulfate mass at smaller sizes in the down wind leg, but its not obvious.

## Local sources of sulfur emissions

-  Sulfate aerosol up wind and down wind of costal sources exhibit different sulfate-to-total sulfur ratios
-  Evidence that SO2 is mixing up from local sources on the eastern seaboard.  High levels of background particulate mass on this day may be inhibiting new particle production.

**Notes:**
Adding in SO2 gas phase data, there does appear to be a difference in the yellow down wind segment compared with the blue (aqua) up wind segment.  The SO2/SO4 ratio is higher for the down wind segment, and there is more structure in the SO2 levels, suggestive of emission plumes.  RHS is a scatter plot comparing the SO4 level (converted to ppbv) to the total sulfur level (SO4+SO2).  Colored by flight segment, the difference in SO2/SO4 ratio is apparent.  The down wind air has a lower sulfate content whereas the up wind segment has a higher sulfate composition. Evidence for SO2 infusion (800 m ~3000ft) from local NE sources.  Interestingly, the addition of SO2 is not correlated with small particle formation and growth in this case.  Potentially, the relatively high mass loadings are inhibiting new particle nucleation.

## Degree of Sulfate Neutralization

-  The degree of sulfate neutralization is sulfate mass loading dependent, suggesting that ammonia is the limiting factor.

**Notes:**
Typically, urban sulfate particles are neutralized with ammonium.  For this experiment, the sulfate was neutralized, regardless of altitude, at low sulfate mass loadings, but the particle became acidic at high sulfate mass loadings.  The ammonia was the limiting factor.

## Morning Traffic Events are “Fresh” Organic Compounds (Mainly Hydrocarbons)

- 0.15

- 0.03

## Observations of Primary Organic Particles

*Traffic Emissions*

-  Evidence of primary organic particles in small particle mode.
-  Small mode typical of primary traffic exhaust emissions

## NEAQS 2002: Vertical Transects

## Slide 46

## The nonrefractory submicron aerosol mass loadings were composed primarily of organics and sulfate species.  Mass loadings were <45 g/m3.

- Air masses passing through the NE region at a constant altitude were influenced by emissions (SO2 and organics) within the coastal area.
- Air masses were found to be vertically layered.  Back trajectories indicate that the polluted layers (July 22nd) were transported from the Ohio River Valley region (outside of the Northeastern region).
- The oxidative ‘age’ of sulfate aerosols in air masses were tracked by the SO4:Stotal ratio, back trajectories, and the size and growth of sulfate particles.  These markers illustrate the influence of local sources in the lower atmosphere and the influx of aerosols from sources outside of the region at altitude.
- Air masses with relatively high SO2 and low sulfate were observed to contain bimodal sulfate size distributions:  small growth mode (from a nucleation event) and accumulation mode.  In contrast, air masses with relatively low SO2 and high particulate sulfate were observed to contain only accumulation mode sulfate particles.
- The sulfate to total sulfur ratio increases with altitude, indicating that higher air masses contained ‘older’, more processed particles.
- The organic components of the aerosol appear highly oxidized and, for the most part, independent of the air mass stratification and/or ‘age’ of the sulfate component.
- Observations of primary “traffic” emissions at lower altitudes down wind of city sources highlight organic emissions from the NE region.

## Slide 48

## Slide 49

## Slide 50

## Stratification of sulfate “aging”

**Notes:**
Further evidence that the upper air mass plumes were not emitted locally comes from the relationship between the sulfate and total sulfur in the aerosol.  In this case, the Sulfate to Total Sulfur ratio is a strong function of the altitude.  The lowest air masses all exhibit a low sulfate composition, whereas the large sulfate plumes exhibit a much higher sulfate fraction.  The sulfur in the air mass measured at 10000 ft (~2500 m) had been fully converted to sulfate.  So if the large sulfate plume was not emitted locally, where did it come from?

## Mass Spectrum of 

- Mass Spectrum of
- Oxidized versus Hydrocarbon containing aerosol

- Hydrocarbon

- Oxidized carbon