SOUTH COAST AIR QUALITY 

MANAGEMENT DISTRICT 

General Aviation Airport Air 

Monitoring Study 

FINAL REPORT 

August 2010 

Prepared for the 

U.S. Environmental Protection Agency, Region IX 

San Francisco, CA 94105 

i 
AUTHORS AND CONTRIBUTORS 

The following individuals contributed to the development, implementation, and reporting 

of this project. 

South Coast Air Quality Management District 

Executive Officer

Barry R. Wallerstein, D.Env. 

Deputy Executive Officer

Chung Liu, D. Env. 

Science and Technology Advancement 

AUTHORS 

Philip Fine Atmospheric Measurements Manager 

Andrea Polidori Air Quality Specialist 

Solomon Teffera Principal Air Quality Chemist 

CONTRIBUTORS 

Libby Ayers Meteorological Technician 

Steven Barbosa Principal Air Quality Chemist 

Paul Chavez Senior Air Quality Instrument Specialist 

Kevin Durkee Senior Meteorologist 

Rudy Eden Senior Laboratory Services Manager 

Sandra Hom Senior Air Quality Chemist 

Dan Houghton Senior Air Quality Chemist 

Judy Hwa Air Quality Chemist 

Aaron Katzenstein Program Supervisor 

Michael Koch Senior Air Quality Instrument Specialist 

Kay Liu Air Quality Chemist 

Jianhang Lu Air Quality Chemist 

Jason Low Quality Assurance Manager 

Paul Mayo Air Quality Instrument Specialist I 

Richard Parent Air Quality Instrument Specialist II 

Tom Parsons Atmospheric Measurements Manager 

Claudius Phipps Senior Air Quality Instrument Specialist 

Edward Ruffino Air Quality Instrument Specialist II 

Yang Song Air Quality Chemist 

Steve Taw Laboratory Technician 

Na Mon Trinh Assistant Air Quality Chemist 

Brian Vlasich Senior Air Quality Instrument Specialist 

Mark Von Der Au Supervising Air Quality Inspector 

Sumner Wilson Principal Air Quality Instrument Specialist 

Robert Yi Air Quality Chemist 

i 
TABLE OF CONTENTS

FIGURE AND TABLE CAPTIONS ......................................................................................................... III

EXECUTIVE SUMMARY ........................................................................................................................ IX

BACKGROUND ................................................................................................................................ IX

OBJECTIVE ....................................................................................................................................... IX

METHODS ......................................................................................................................................... IX

KEY FINDINGS .................................................................................................................................. X

CONCLUSIONS AND RECOMMENDATIONS ............................................................................. XII

INTRODUCTION ........................................................................................................................................ 1

REGULATORY BACKGROUND ..................................................................................................... 1

AIRCRAFT EMISSIONS .................................................................................................................... 1

RESULTS FROM PREVIOUS STUDIES ........................................................................................... 3

CURRENT STUDY ON GENERAL AVATION ................................................................................ 5

The Van Nuys Airport (VNA) ........................................................................................................ 6

The Santa Monica Municipal Airport (SMO) ............................................................................... 7

METHODS.................................................................................................................................................... 7

MONITORING SITES AT THE VAN NUYS AIRPORT ................................................................... 7

Van Nuys Airport Sampling Loctions ........................................................................................... 9

MONITORING SITES AT THE SANTA MONICA AIRPORT ....................................................... 10

Santa Monica Airport Sampling Location .................................................................................. 11

MEASURED POLLUTANTS ........................................................................................................... 13

SAMPLING SCHEDULE ................................................................................................................. 13

LABORATORY ANALYSIS ............................................................................................................ 14

RESULTS AND DISCUSSION ................................................................................................................. 16

METEOROLOGY ............................................................................................................................. 16

Van Nuys Airport ........................................................................................................................ 16

Santa Monica Airport ................................................................................................................. 17

LEAD................................................................................................................................................. 18

Van Nuys Airport ........................................................................................................................ 18

Santa Monica Airport ................................................................................................................. 20

EAST TARMAC SITE (METHOD COMPARISON) ....................................................................... 22

VOLATILE ORGANIC COMPOUNDS (VOC) ............................................................................... 24

Van Nuys Airport ........................................................................................................................ 25

Santa Monica Airport ................................................................................................................. 28

EIGHT-HOUR VOC ......................................................................................................................... 31

Van Nuys Airport ........................................................................................................................ 31

Santa Monica Airport ................................................................................................................. 33

CARBONYLS ................................................................................................................................... 34

Van Nuys Airport ........................................................................................................................ 34

Santa Monica Airport ................................................................................................................. 36

PM2.5 MASS, ELEMENTAL AND ORGANIC CARBON ............................................................... 38

Van Nuys Airport ........................................................................................................................ 38

Santa Monica Airport ................................................................................................................. 41

ULTRAFINE PARTICLES ............................................................................................................... 44

Van Nuys Airport ........................................................................................................................ 44

 Phase 1(November 2005 - March 2006) .......................................................................... 44

 Phase 2 (July - September, 2006) .................................................................................... 47

 

i 
Santa Monica Airport ........................................................................................................................ 50

 Phase 1(April - July, 2006) .............................................................................................. 50

 Phase 2 (October 2006 - February 2007) ........................................................................ 55

DAILY CARBON MONOXIDE (CO) VARIATIONS ..................................................................... 58

TRACE ELEMENTS ......................................................................................................................... 61

JET SIGNATURES ........................................................................................................................... 64

CONCLUSIONS AND RECOMMENDATIONS .................................................................................... 70

ACKNOWLEDGEMENTS ....................................................................................................................... 71

REFERENCES ........................................................................................................................................... 72

APPENDIX A ............................................................................................................................................ 77

ii 
iii 

FIGURE AND TABLE CAPTIONS 

Figure 1 A current aerial view of the Van Nuys Airport 

Figure 2 A current aerial view of the Santa Monica Airport 

Figure 3 Map of the Van Nuys Airport sampling sites. Yellow and blue circles represent 

“fully” and “partially” instrumented sites, respectively (see text for details) 

Figure 4 Map of the Santa Monica Airport sampling sites. Yellow and blue circles 

represent “fully” and “partially” instrumented sites, respectively (see text for details) 

Figure 5 Average wind speed and direction at the Van Nuys Airport during a) Phase 1 

(November 2005 - March 2006) and b) Phase 2 (July - September, 2006) 

Figure 6 Average wind speed and direction at the Santa Monica Airport during a) Phase 

1 (April - July, 2006) and b) Phase 2 (October 2006 - February 2007)

Figure 7 Box plots showing the median and mean lead concentrations in total suspended 

particles (black and red lines within each box, respectively) (ng/m3) measured at the Van 

Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Representative lead levels for the South Coast Basin are also reported 

for comparison. Data collected during Phase 2 have been magnified on the top right panel 

to facilitate a comparison among sites 

Figure 8 Box plots showing the median and mean lead concentrations in total suspended 

particles (black and red lines within each box, respectively) (ng/m3) measured at the 

Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 (October 2006 - 

February 2007). The correspondent lead levels for the South Coast Basin have also been 

reported for comparison 

Figure 9 Comparison between lead concentrations obtained from XRF and ICP-MS 

analyses of selected TSP samples collected at the East Tarmac site (Santa Monica 

Airport) during Phase 1 

Figure 10 Box plots showing the median and mean lead concentrations (ng/m3

) in fine 

particulate matter (PM2.5) measured at four monitoring sites of the Santa Monica Airport 

(black and red lines within each box, respectively) during Phase 1 (April - July, 2006) 

and Phase 2 (October 2006 - February 2007). Lead levels for the South Coast Basin 

(same time periods) and at MATES III sites (from April 2005 to March 2006 only) are 

shown for comparison 
iv 

Figure 11 Spatial distributions of a) 1,3-butadiene, methylene chloride, and chloroform, 

b) benzene, carbon tetrachloride, and toluene, and c) perchlroethylene at 5 monitoring 

sites of the Van Nuys Airport (i.e. Golf Course, Holmes School, VOR, and National 

Guard sites) during Phase 1 (November 2005 - March 2006) and Phase 2 (July 200 - 

September, 2006). Data collected concurrently at a monitoring station in Burbank are also 

included for comparison 

Figure 12 Spatial distributions of a) 1,3-butadiene, methylene chloride, and chloroform, 

b) benzene, carbon tetrachloride, and toluene, and c) trichloroethane and 

perchloroethylene at selected monitoring sites of the Santa Monica Airport (i.e. Richland 

School, Marine Park, Ernst Residence, East Tarmac, West Tarmac sites) during Phase 1 

(April - July, 2006) and Phase 2 (October 2006 - February 2007). Data collected 

concurrently at a monitoring site in Central Los Angeles are also included for comparison 

Figure 13 Percentage contribution of volatile organic compounds (VOCs) measured at 

the VOR site during three 8-hr intervals (i.e. 00:00 to 08:00, 08:00 to 16:00, and 16:00 to 

00:00) to the corresponding 24-hr average concentrations. The two panels refer to a) 

Phase 1 (November 2005 - March 2006) and b) Phase 2 (July - September, 2006) data 

Figure 14 Percentage contribution of volatile organic compounds (VOCs) measured at 

the West Tarmac site during three 8-hr intervals (i.e. 00:00 to 08:00, 08:00 to 16:00, and 

16:00 to 00:00) to the corresponding 24-hr average concentrations. The two panels refer 

to a) Phase 1 (April - July, 2006) and b) Phase 2 (October 2006 - February 2007) data 

Figure 15 Spatial distributions of formaldehyde, acetaldehyde, acetone, and methyl ethyl 

ketone (MEK) at selected monitoring sites of the Van Nuys Airport (i.e. Golf Course, 

Holmes School, VOR, and National Guard sites) during Phases 1 and 2. Data collected at 

an AQMD monitoring station in Burbank are also included for comparison 

Figure 16 Spatial distributions of formaldehyde, acetaldehyde, acetone, and methyl ethyl 

ketone (MEK) at selected monitoring sites of the Santa Monica Airport (i.e. Richland 

School, Marine Park, Ernst Residence, East Tarmac, and West Tarmac sites) during 

Phases 1 and 2. Data collected at an AQMD monitoring station in Central Los Angeles 

are also included for comparison 

Figure 17 Spatial distributions of fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) at selected monitoring sites of the Van Nuys Airport 

(i.e. Golf Course, Holmes School, VOR, and National Guard sites) during Phases 1 and 2. 

Data collected at an AQMD monitoring station in Burbank are also included for 

comparison 

Figure 18 Spatial distributions of fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) at selected monitoring sites of the Santa Monica 

Airport (i.e. Richland School, Marine Park, Ernst Residence, East Tarmac, and West 

Tarmac sites) during Phases 1 and 2. Data collected at an AQMD monitoring station in 

Central Los Angeles are also included for comparison 
v 

Figure 19 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3

) at the Van Nuys Airport measured from 02/10/06 to 02/28/06. Hourly data were 

averaged from 1-min values to facilitate comparison among sites (top panel). An example 

of more resolved 1-min data is shown in the magnified portion of the graph within broken 

lines 

Figure 20 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3) measured at three sites of the Van Nuys Airport (i.e. Golf Course, VOR, and 

Holmes School stations) during Phase 1 (November 2005 - March 2006) 

Figure 21 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3) at the Van Nuys Airport measured between 09/01/06 and 09/18/06. Hourly data 

were averaged from 1-min measurements to facilitate comparison among sites (top 

panel). An example of more resolved 1-min data showing elevated UFP levels from 

09/07/06 to 09/09/06 is illustrated in the magnified portion of the graph within broken 

lines

Figure 22 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3

) measured at three sites of the Van Nuys Airport (i.e. Golf Course, VOR, and 

National Guard stations) during Phase 2 (July - September, 2006) 

Figure 23 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3) at the Santa Monica Municipal Airport measured from 05/03/06 to 05/24/06. 

Hourly data were averaged from 1-min measurements to facilitate comparison among 

sites (top panel). An example of more resolved 1-min data showing elevated UFP levels 

from 05/11/06 to 05/12/06 is illustrated in the magnified portion of the graph within 

broken lines

Figure 24 Ultrafine particle (UFP) number concentrations data showing the impact of 

aircraft movements at the East Tarmac, Ernst Residence, West Tarmac, Richland 

Elementary School sites on 07/07/06 

Figure 25 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3

) measured at five sites of the Santa Monica Airport (i.e. East Tarmac, West 

Tarmac, Ernst Residence, Richland School, and Marine Park) during Phase 1 (April - 

July, 2006) 

Figure 26 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3) at the Santa Monica Municipal Airport measured from 01/01/07 to 01/23/07. 

Hourly data were averaged from 1-min measurements to facilitate comparison among 

sites (top panel). An example of highly resolved 1-min data showing elevated UFP levels 

from 01/02/07 to 01/03/07 is illustrated in the magnified portion of the graph within 

broken lines 
vi 

Figure 27 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3

) measured at four sites of the Santa Monica Airport (i.e. East Tarmac, West 

Tarmac, Ernst Residence, and Richland School) during Phase 2 (October 2006 - February 

2007) 

Figure 28 Average diurnal variations of carbon monoxide (CO; ppm) at four sites of the 

Van Nuys Airport (i.e. Golf Course, VOR, Holmes School and National Guard). 

Measurements were taken from a) November 2005 to March 2006 (Phase 1) and b) 

between July and September 2006 (Phase 2). Because of a malfunctioning of several 

monitors deployed at VNA and issues related to data recovery, CO concentrations for 

Phase 1 are only available at the VOR site 

Figure 29 Average diurnal variations of carbon monoxide (CO; ppm) at different four 

sites of the Santa Monica Municipal Airport, namely West Tarmac, Ernst Residence, 

Richland School, and Marine Park. Measurements were taken a) from April to July 2006 

(Phase 1) and b) between October 2006 and March 2007 (Phase 2) 

Figure 30 Ambient concentrations of selected metals in fine particulate matter (PM2.5) at 

different sampling locations of the Van Nuys Airport during a) Phases 1 (from November 

2005 to March 2006) and b) Phase 2 (from July to September 2006) 

Figure 31 Ambient concentrations of selected metals in fine particulate matter (PM2.5) at 

different sampling locations of the Santa Monica Airport during a) Phase 1 (from April to 

July 2006) and b) Phase 2 (from October 2006 to March 2007) 

Figure 32 Comparison between the emission profiles of the two canister samples 

collected at the East Tarmac site and those of a) jet fuel, b) diesel exhausts, and c) 

gasoline vehicle emissions. Data are expressed as the percentage weight contribution of 

each species to the total measured organic gas concentration. The emission profiles of jet 

fuel exhaust (aircraft exhaust - jet fuel), typical gasoline vehicle emissions (gasoline - 

catalyst - stabilized exhaust - ARB summer 2003), and diesel exhaust (farm equipment - 

diesel - light & heavy) were downloaded from the California Air Resource Board 

(CARB) speciation database for organic compounds (ORGPROF; 

http://www.arb.ca.gov/ei/speciate/speciate.htm) 

Figure 33 Comparison between the hazardous air pollutants (HAPs) speciation profile 

for commercial aircraft engines emission profiles provided by EPA (Aircraft Engine 

Speciated Organic Gases: Speciation of Unburned Organic Gases in Aircraft Exhaust, 

prepared by EPA in 2009) and those of the two canister sample collected at the East 

Tarmac site when jets were either idling or taking-off (sample #1; bottom panel) and 

when no aircraft activity was ongoing (sample #2; top panel) 

Table 1 List of the most relevant particle and gaseous species monitored during this 

study at both the Van Nuys and Santa Monica Airports 

Table 2 Sampling schedule for the Van Nuys and Santa Monica Airports 
vii 

Table 3 Sampling and analysis methods 

Table 4 Average and median lead concentrations in total suspended particles (ng/m3

) at 

the Van Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid samples (Valid N) have also been reported along with 

representative lead data for the South Coast Basin (in red) 

Table 5 Average and median lead concentrations in total suspended particles (ng/m3

) at 

the Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 (October 2006 

- February 2007). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid samples (Valid N) have also been reported along with 

representative lead data for the South Coast Basin (in red)

Table 6 Average and median fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) concentrations (μg/m3

) at the Van Nuys Airport 

stations and at an urban site in Burbank (CA) during Phase 1 (November 2005 - March 

2006) and Phase 2 (July - September, 2006). Minimum (Min) and maximum (Max) 

values, standard deviations (SD), and the total number of valid samples (Valid N) have 

also been included 

Table 7 Average and median fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) concentrations (μg/m3

) at the Santa Monica Airport 

stations and at an urban site in Central Los Angeles (CA) during Phase 1 (April - July, 

2006) and Phase 2 (October 2006 - March 2007). Minimum (Min) and maximum (Max) 

values, standard deviations (SD), and the total number of valid samples (Valid N) have 

also been included 

Table 8 Average and median ultrafine particle (UFP) number concentrations (μg/m3) at 

the Van Nuys Airport stations during Phase 1 (November 2005 - March 2006). Minimum 

(Min) and maximum (Max) values, standard deviations (SD), and the total number of 

valid samples (Valid N) have also been included 

Table 9 Average and median ultrafine particle (UFP) number concentrations (μg/m3

) at 

the Van Nuys Airport stations during Phase 2 (July - September, 2006). Minimum (Min) 

and maximum (Max) values, standard deviations (SD), and the total number of valid 

samples (Valid N) have also been included 

Table 10 Average and median ultrafine particle (UFP) number concentrations (#/cm3) at 

the Santa Monica Airport stations during Phase 1 (April - July, 2006). Minimum (Min) 

and maximum (Max) values, standard deviations (SD), and the total number of valid 

samples (Valid N) have also been included 

Table 11 Santa Monica Airport take-off observation data on 7/17/2006. Time periods 

associated with the particle number concentration peaks in Figure 24 are highlighted in 

red 
viii 

Table 12 Average and median ultrafine particle (UFP) number concentrations (#/cm3) at 

the Santa Monica Airport stations during Phase 2 (October 2006 - March 2007). 

Minimum (Min) and maximum (Max) values, standard deviations (SD), and the total 

number of valid samples (Valid N) have also been included 

Table 13 Ambient concentrations (ppb) of several important gaseous pollutants present 

in canister samples collected at the East Tarmac site (samples #1 and #2) and behind the 

blast-fence (sample #3) at SMO 
ix 

EXECUTIVE SUMMARY 

BACKGROUND 

The Van Nuys and Santa Monica Municipal Airports (VNA and SMO, 

respectively) are among the most important general aviation airports (GA) in the South 

Coast Air Basin. In 2005, VNA was the world's busiest GA airport with around 450,000 

takeoffs and landings annually, while SMO is the oldest operating GA airport in Los 

Angeles County. Both airports are surrounded by public areas and private residences, and 

odor and/or noise complaints by people living in nearby communities have raised 

concerns about possible health effects from exposure to gaseous and particle pollutants 

emitted from the airport areas. 

OBJECTIVE 

Conducted as part of a Community-Scale Air Toxics Ambient Monitoring Grant 

from the U.S. Environmental Protection Agency (U.S. EPA), the main goal of this study 

is to characterize the ambient levels of several important air toxics in communities 

adjacent to VNA and SMO. Since GA aircraft with piston-driven engines use leaded 

gasoline, lead monitoring was a major focus of this study. Also, because jet turbine 

engines emit substantial amounts of ultrafine particles (UFPs) and other combustionrelated pollutants, attention was given to the monitoring of the particle number 

concentration (an indicator of UFPs). Recent studies conducted at the Los Angeles 

International Airport (LAX) and at SMO (Fanning et al., 2007; Westerdahl et al., 2008; 

Hu et al., 2009) have shown that UFP levels are higher in areas adjacent to and 

downwind of the airport runways. Volatile organic compounds (VOCs), carbonyl 

compounds, fine particulate matter (PM2.5) and some of its organic and inorganic 

components (i.e. organic and elemental carbon, and trace elements) were also measured 

at VNA and SMO. Although the monitoring approach was designed to focus on longterm exposures, the potential for short-term exposures was examined by continuous 

measurements of UFP and carbon monoxide (CO). 

METHODS 

The monitoring strategy included deployment of sampling equipment near 

runways and at locations in the community under the flight path to detect and 

characterize pollution levels and exposure gradients caused by airport emissions. The 

sampling protocols were primarily based on previous AQMD air toxics studies such as 

the Multiple Air Toxics Exposure Study (MATES-III). Sites that were placed upwind and 

downwind of each airport included a full array of integrated samplers (for the collection 

of total suspended particles for lead analysis, selected VOCs, carbonyls, and metals) and 

continuous analyzers (for UFP and CO measurements). Other locations situated to the 

sides of the runways were monitored using lead samplers and CO sensors only. Sampling 

was conducted for two different periods at each airport to assess the seasonal variability 

of the measured pollutants. Each monitoring period lasted for a nominal three months. 

The first phase of sampling at VNA was from 11/22/2005 to 3/3/2006. This was followed 
x 

by a field campaign at SMO from 4/26/2006 to 7/19/2006. The second sampling 

campaign in Van Nuys was conducted from 7/28/2006 to 9/29/2006, followed by 

measurements in Santa Monica from 10/20/2006 to 3/1/2007. Integrated and continuous 

data from the analysis of all collected samples were analyzed to assess the levels of air 

toxics in the communities relative to other areas of Southern California. The data were 

also examined to determine, if possible, the contribution of airport-related emissions and 

those from other potential pollution sources (such as local traffic) on the measured 

ambient levels. Meteorological data at VNA and SMO were provided by the local airport 

authorities. 

KEY FINDINGS 

• The 24-hr average total suspended particulate (TSP) lead concentration gradient at 

the Van Nuys and Santa Monica Airports reflected the relative distance of the 

various monitoring sites from the runway areas. This indicates that piston-driven 

aircraft and the leaded fuel they use were sources of TSP lead at the monitored 

stations. Daily average TSP lead concentrations at VNA and SMO sites were 

substantially higher (up to two and nine times higher, respectively) than the 

corresponding South Coast Basin levels during the same time periods, and mostly 

below the new national ambient air quality standard (NAAQS) of 150 ng/m3

. 

However, 24-hr average concentrations close to, or above the current NAAQS for 

lead were recorded at SMO near the Tarmac in more than one occasion and 

during both phases of the study. In addition to direct aircraft exhaust 

contributions, decades of aircraft exhaust emissions may have caused lead 

accumulation in the soil on which the samplers were located. A recent study 

conducted by U.S. EPA regarding lead emissions from SMO included soil 

analysis for lead (U.S. EPA, 2010). However, results from the analysis of samples 

collected at SMO using the PM2.5 speciation samplers indicates that the majority 

of particulate lead is present in the fine fraction, suggesting that a relatively high 

proportion of lead at this airport was not associated with re-suspended material. 

• The atmospheric levels of VOCs at VNA and SMO stations were mostly 

influenced by their proximity to busy surface streets surrounding the airports’ 

perimeters and nearby freeways. However, the contributions of these and other 

potential pollution sources (including airport-related emissions) to the measured 

VOC and carbonyl levels could not be assessed from the available data. The 

highest VOC concentrations measured at VNA and SMO were generally 

comparable to or lower than those observed at two companion urban monitoring 

sites (Burbank and Central Los Angeles, respectively), where motor-vehicles 

emissions dominate the atmospheric levels of most primary pollutants. 

 

• The mass concentrations of PM2.5, organic carbon (OC) and elemental carbon 

(EC) at all Van Nuys and Santa Monica stations were at or below the 

corresponding South Coast Basin averages. Comparisons among sampling sites 

did not show any significant spatial or temporal gradient that could be attributed 

to aircraft operations. It is likely that other local and regional sources (e.g. motor-
xi 

vehicle emissions from nearby traffic and atmospheric transport of aged 

pollutants, respectively) were mainly responsible for the observed atmospheric 

levels of PM2.5 and its carbonaceous components. 

• Aircraft idling near the runway before departure and during take-off were found 

to generate large numbers of UFPs over short time periods. Continuous (1-

minute) particle number levels up to 600 times higher than those measured in 

background air were observed both in Van Nuys and in Santa Monica, including 

at a residential site located less than 100 m downwind of SMO. Emissions from 

major freeways and surface streets surrounding both airports are another source of 

UFPs, but the largest short term increases were often not consistent with motorvehicle sources. Further work is needed to better define the contribution of 

aircraft to community UFP exposures with respect to specific aircraft and airport 

operations. 

• The average diurnal profile of CO at the Van Nuys and Santa Monica stations 

followed a distinctively different pattern from that observed for other combustionrelated pollutants such as UFP count and EC, with peak values during morning 

rush hour traffic and lower levels in the afternoon. This suggests that the 

concentration of this gaseous pollutant was dominated by contributions from 

motor-vehicle emissions from nearby roadways/freeway and surface streets, and 

that the influence from airport-related activities was not significant. 

 

• Our results suggest that the majority of the trace elements detected in the PM2.5

samples collected at both airports originated from re-suspension of crustal 

materials. The atmospheric concentrations of all measured metals are comparable 

to those reported in previous studies conducted in the South Coast Air Basin. 

• An analysis of the VOC profile of two canister samples collected at SMO near the 

blast-fence when jet-propelled planes were idling close to the runway and when 

no airplane activity was occurring revealed that emissions from aircrafts idling 

before departure increased the concentration of all combustion-related VOCs 

substantially. The speciation profile of the idling sample closely resembles that of 

typical jet exhaust, indicating that short-term VOC levels near the runway were 

influenced by aircraft emissions when jets were idling before take-off. 

Conversely, the emission profile of the other sample is similar to that of diesel 

truck emissions; when no airplane activity was taking place, the ambient air was 

probably affected by diesel emissions from vehicles operating within or in close 

proximity of the airport’s perimeter. Lastly, the VOC profiles of both these 

samples differ from that of gasoline vehicle exhaust, indicating that gasolinepowered vehicles did not influence the composition of the two canister samples at 

the time of sampling. 

• Overall, the atmospheric concentrations of most of the measured air toxics were 

higher during the winter months than in the summer period. This seasonal pattern 

of air toxics levels is similar to that observed in previous studies in the South 
xii 

Coast Air Basin. In the late fall and early winter, light winds result in reduced 

ventilation, and overnight inversions contribute to increasing surface-level 

concentrations of those pollutants that are emitted from ground-level sources. 

During the summer months, stronger on-shore breezes and atmospheric 

circulation due to increased solar insulation results in higher wind speeds, 

increased vertical atmospheric dispersion and, subsequently, reduced ambient 

concentrations at ground level. 

CONCLUSIONS AND RECOMMENDATIONS 

 Overall, the most significant airport-related impacts on air quality were observed 

for lead and for UFPs. Airport impacts on other pollutant levels were difficult to 

determine, but appeared to be minor when considering long-term averages. This study 

focused on longer-term exposure as it was based on MATES-III sampling protocols. 

Shorter term impacts may be present, such as those observed for UFPs, instantaneous 

VOCs, and odors. Further investigation into short-term impacts would require a different 

study design with more continuous measurements, although continuous instruments for 

some air toxics are not commercially available. Future work may also include more 

detailed measurements of UFP levels correlated to aircraft type and aircraft operations. 
1 

INTRODUCTION 

REGULATORY BACKGROUND 

Questions regarding the impact of airport related pollution on local air quality 

arose in the 1960s. The first comprehensive studies on aircraft’s emissions were 

conducted by the then Los Angeles County Air Pollution Conctrol District in 1960 and 

1965 (Bastress 1973). Their results indicated that aircraft contributed to a small but 

significant fraction of the pollutants emitted in the Los Angeles County. However, the 

integrated and centralized assessment and gathering of data in a regulatory framework 

started after the Clean Air Act (CAA) of 1970 was passed by the United States Congress. 

CAA gave the Environmental Protection Agency (EPA) the right to establish air pollution 

standards, including those applicable to aircraft exhaust. Section 231(a)(2)(A) of the 

CAA directs the EPA administrator to “issue proposed emission standards applicable to 

the emission of any air pollutant from any class or classes of aircraft or aircraft engines 

which in his judgment causes, or contributes to, air pollution which may reasonably be 

anticipated to endanger public health or welfare”. Under this authority EPA has 

conducted several rulemakings since 1973, establishing emission standards and related 

requirements for several classes of aircrafts and aircraft engines, including commercial 

and general aviation engines. Although airports don’t meet the definition of “area” or 

“major” source under section 112 of the CAA, the EPA has taken a “combinations of 

sources” approach to tackle the issue of airport emissions and their impact on the 

surrounding communities. To this end, EPA released a report in April 1999 that assessed 

the potential impact of aircraft emissions on local air quality at ten selected airports (U.S. 

EPA, National Emission Trends, Average Annual Emissions, All Criteria Pollutants, 

1970-2001, August 13, 2003). 

The International Civil Aviation Organization (ICAO) was created by the United 

Nations in 1947 to "achieve maximum compatibility between the safe and orderly 

development of civil aviation and the quality of the human environment". The United 

States is one of more than 150 participating members or "Contracting States" of this 

organization. To achieve its objective, ICAO established exhausts emissions standards 

and test procedures for three pollutants: hydrocarbons (HCs), carbon monoxide (CO), and 

oxides of nitrogen (NOx), that are expected to be met by each of the Contracting States. 

Throughout the past few decades numerous and increasingly stringent standards have 

been set by ICAO to reduce aircraft emissions, and in 2005 EPA amended the existing 

emission standards for NOx for new commercial aircraft engines (EPA, 2005) to bring 

the United States aircraft standards into alignment with the international guidelines. 

These standards apply to new aircraft engines utilized on small regional jets, single-aisle 

airplanes, twin-aisle aircrafts, and other larger commercial units. 

AIRCRAFT EMISSIONS 

In addition to the carbon dioxide (CO2) released by airplanes in flight through the 

burning of fuels [such as jet-A for turbine aircraft, or aviation gas (Avgas) for piston 

aircraft], other important pollutants are typically present in aircraft emissions. These 

include CO, nitrogen dioxide (NO2) and nitrogen monoxide (NO), water vapor, sulfur 
2 

oxides (SOx), incompletely-burned HCs, transition metals (e.g. lead) and particulate 

matter (PM) of various sizes (http://epa.gov/oms/aviation.htm). Ultrafine particles [UFP; 

particle diameter (Dp) ≤ 0.10 μm] are the biggest contributor to the total particle number 

concentration and have the highest potential to penetrate deeply into the human lungs. In 

a recent study conducted by Ntziachristos et al. (2007a), size-fractionated ambient PM 

samples [i.e. UFP, accumulation (Dp ≤ 2.5μm), and coarse (2.5 μm ≤ Dp ≤ 10 μm) mode 

particles] were collected at four different locations in the Los Angeles Basin, and 

analyzed for their redox potential (an indicator of particle toxicity; Cho et al, 2005; Geller 

et al., 2006). The ultrafine fraction had the highest redox activity on a per-PM mass basis. 

No health-based standards are currently in place for this important PM fraction. 

Emissions from airports are associated with both direct emission (i.e. aircraft exhaust) 

and different airport activities including refueling, pre-flight safety procedures, and fuel 

venting (Federal Aviation Administration; http://www.faa.gov/regulations_policies/). 

In the Los Angeles metropolitan area the combustion of gasoline and other 

hydrocarbon fuels in automobile, trucks, airplanes and marine vessels represent the main 

sources of PM (including UFP), transition metals, volatile organic compounds (VOCs), 

CO, NOx, and other primary emitted pollutants. In order to improve our understanding of 

the toxic risk associated with exposure to these particulate and gaseous species, it is 

important to characterize the contribution and spatial distribution of the most important 

mobile, point and areas sources, and their relative impact on nearby communities. 

Although most of the air toxic studies on combustion-related species have focused on 

motor-vehicles emissions, the contribution of aircraft emissions to air toxic exposure 

levels should be examined for individuals living in close proximity of an airport area. 

The term “general aviation” (GA) refers to most of the aircraft used for 

recreational flying and personal transportation. Airplanes that support business travel, 

usually on an unscheduled basis, are also included in this category. General aviation 

flights range from gliders and powered parachutes to large, non-scheduled cargo jet 

flights. As a result, the majority of the world's air traffic falls into this category, and most 

of the world's airports serve GA exclusively. One of the fastest growing areas in the GA 

sector is that of small passenger aircraft and cargo for short distance. These airplanes, 

usually smaller than those operated by major carriers and often referred to as “air taxis”, 

provide scheduled services by carrying passengers, freight, or both. Air taxis have been 

playing an increasingly important role in the U.S. aviation system, and by 2015 such 

operations are forecast to represent 54% of total air traffic 

(http://www.apo.data.faa.gov/main/taf.asp; U.S. EPA Average Annual Emissions, All 

Criteria Pollutants Years Including 1980, 1985, 1989–2001, February 2003). 

Most GA aircraft are powered by piston engines and are fueled by Avgas [one 

hundred octane low lead aviation gas (100LL Avgas) is the most commonly available 

type of aviation gasoline in the United States], which is characterized by a higher 

volatility and lead content than other gasoline fuels. Lead is added to the fuel as tetraethyl 

lead, an additive that boosts fuel octane and prevents valve seat recession, which can be a 

significant concern from a safety standpoint. Lead is not present in the jet fuel that is used 

in commercial, military, or other turbine-engine powered aircrafts. 
3 

RESULTS FROM PREVIOUS STUDIES 

Unlike the present work, the vast majority of the studies that examined the impact 

of airport operations on local air quality focused on emissions from very large 

commercial aircraft. Spicer et al. (1984) first reported NOx, CO, PM, and speciated HC 

emission rates from jet aircraft turbine engines. Further studies by Spicer et al. (1992, 

1994) provided additional information on the detailed organic composition of turbine 

engine exhausts, and revealed that during engine idle, emissions were dominated by 

products from fuel cracking, unburned fuel and products of incomplete combustion, with 

ethene, propene, acetylene and formaldehyde comprising 30–40% of the total HC 

emissions. 

Between 1998 and 2001, the South Coast Air Quality Management District 

(AQMD) conducted a series of monitoring campaigns at several locations surrounding 

the Los Angeles International Airport (LAX) (AQMD 1998, 2000a, 2000b, 2001). PM10

(Dp ≤ 10 μm), organic and elemental carbon (OC and EC, respectively), CO, and VOCs 

(e.g. benzene, 1,3 butadiene, and formaldehyde) concentrations were measured with time 

resolutions between 8 and 24 hours and were found to be higher than the corresponding 

ambient levels away from the airport. The relative contribution of LAX aircraft emissions 

to the total measured pollutant concentrations could not be estimated, mainly because 

more resolved (e.g. hourly) data were not available, and because vehicular emissions 

from heavily trafficked roads nearby (e.g. Aviation Boulevard and the 405 Freeway) may 

have influenced the atmospheric concentration of the targeted compounds. 

In 2000, AQMD undertook a study at Felton Elementary School and Lloyde High 

School in response to community concerns about the impact of the pollutants emitted 

from the LAX and the 405 Freeway on local air quality (Air Monitoring Study at Felton 

and Lloyde Schools, September 2001, South Coast Air Quality Management District). 

The results indicated that concentrations of all monitored air contaminants (with the 

exception of carbonyl compounds) at these schools were at or below the average levels 

for the Los Angeles Basin. Increased concentrations of carbonyl species were probably 

related to emissions from both LAX and the heavily trafficked 405 Freeway. A proposed 

plan to conduct a more comprehensive air monitoring study with measurements within 

and outside the airport was delayed due to the September 11, 2001 incident. This 

monitoring campaign is currently planned to be conducted by Los Angeles World 

Airports, the operator of LAX, for 2011. 

A more recent field study was conducted in 2003 by Westerdahl et al. (2008) to 

determine how emissions from LAX affect the ambient air of a nearby residential 

neighborhood located downwind of the airport. A mobile air monitoring platform was 

deployed to measure UFP number, black carbon (BC), NOx and particle-bound 

polycyclic aromatic hydrocarbons (p-PAHs) concentrations and the particle size 

distribution. Ultrafine particle counts at an upwind coastal site (580-3,800 #/cm3

) were 

substantially lower than those observed 500 m downwind of the airport (~50,000 #/cm3) 

in a residential area. Black carbon, p-PAHs, and NOx levels were also elevated at 

locations further downwind, but to a lesser extent. Peaks of about 5×106

 #/cm3 were 

occasionally measured downwind of a runway used by jet aircrafts for take-off. The size 

distributions found at the upwind and downwind sites were dominated by particles with 

mode diameters of ~90 and ~10-15nm, respectively. 
4 

A similar study was conducted by the California Air Resource Board (CARB) and 

the University of California, Los Angeles (UCLA), in 2005-2006 (Fanning et al., 2007) 

to monitor UFP and BC levels at and in the vicinity of the LAX. Near real-time 

instruments were employed to measure the number concentrations and the size 

distribution of UFP from aircraft emissions, and to capture the corresponding temporal 

variability. Increased number concentrations of UFP with a mode diameter of around 14 

nm were found downwind of an area where aircrafts were taking-off, and the total UFP 

counts exceeded 107 #/cm3 in some occasions, consistent with the findings of Westerdahl 

et al., 2008. Number concentrations of UFP were lower at a residential community 2-3 

km east of the LAX, but still higher than those at a background reference site located 

further away. Time averaged levels of PM2.5 mass, formaldehyde, and acrolein were 

elevated at the airport sites relative to those at a background location. However, the 

concentrations of most VOCs were around or below the corresponding Los Angeles 

Basin average values. Despite the influence of airport emissions on the UFP count 

observed at this residential community, no increase in the exposure levels to any of the 

other measured pollutants were found. 

During a monitoring study conducted in 2006 at the Teterboro Airport (TEB; one 

of the busiest GA airports in the United States located in Teterboro, New Jersey), 

ENVIRON Corp. measured the concentrations of selected air toxics at the airport fenceline, and evaluated the associated risks to human health (Teterboro Airport, New Jersey, 

Detailed Air Quality Evaluation, Final Report Prepared by ENVIRON Corp. in 2008). 

Four sampling stations were set-up to monitor PM2.5, BC, and selected VOCs and 

carbonyls. The median, mean, and maximum concentrations of certain VOCs 

(formaldehyde and toluene in particular) were significantly higher than those measured 

further from TEB, where concentrations are typically dominated by mobile source 

emissions (such as in Elizabeth, New Jersey). The atmospheric concentrations of other 

VOCs detected around TEB (e.g., benzene, acetaldehyde) were comparable to those at 

other “representative” New Jersey locations. A conservative risk assessment was also 

conducted to estimate the health implications of these monitoring data. Between 75 and 

87% of the cancer risk associated with the concentrations of VOCs detected at the 4 

monitored locations was associated with formaldehyde exposure. Although the PM2.5 and 

BC levels measured around the TEB area appeared to be higher than those at other New 

Jersey monitoring locations, the data were insufficient to quantify the contributions from 

airport activities, which are highly dependent on wind direction and wind speed. 

Another relevant study was conducted in September 2004 at the HartsfieldJackson International Airport (one of the world’s busiest airports both in terms of 

numbers of aircraft and numbers of passengers conveyed) in Atlanta, Georgia, to 

characterize commercial aircraft engine emissions of in-use aircrafts (Herndon et al., 

2008). A mobile laboratory was set-up downwind of the active runway and taxiway, 

inside the airport fence-line. Emissions from in-use commercial aircraft engines were 

analyzed continuously for selected gaseous and particle species (e.g. CO, NOx and BC) 

and particle characteristics (e.g. particle number concentration and size distribution). The 

CO emission index (i.e. amount of CO emitted per Kg of fuel burnt) observed in ground 

idle plumes was up to 100% greater than that predicted by engine certification data 

provided by ICAO at 7% thrust conditions. Significant differences were also observed in 

the emissions of BC and particle number among different aircrafts and engine 
5 

models/technologies, suggesting that total emissions of gaseous and particle pollutants 

from aircraft exhausts might be misrepresented (or under estimated) in current 

inventories such as the ICAO databank (see Herndon et al. 2009 for more details). 

Therefore, this study concluded that there is a need to revise the current information 

about emissions of air contaminants from modern aircraft engines run under different 

operating conditions (e.g. idle, take-off and cruise). 

Similar studies on air pollutant emissions from aircrafts and airport-related 

activities have also been conducted at several European cities. For example, during the 

AIRPUR project Lelievre et al. (2006) characterized the physical and chemical 

characteristics of various gaseous and particle pollutants at the Charles de Gaulle (CDG) 

Airports in Paris, France, using various real-time, integrated and remote sensing 

techniques, and investigated the influence of these emissions on local air quality. 

Measurements of PM, UFP number, soot, CO, NOx, and speciated VOCs were taken 

three days in late 2004 and seven days in early 2005 at aprons, beside taxiways and 

runways, at engine test areas, along roads, and at airport landscape areas. Sampling 

performed inside engine plumes for different power settings showed a maximum in UFP 

number on the order of 106

 #/cm3 at 7-10 nm in diameter, while the number concentration 

of the soot mode (20-40 nm) was a factor of 100 lower. The analysis of the collected 

filter samples revealed the presence of aggregated soot (20-40 nm) and aerosols 

containing some proportion of S, Si, Fe, Ca, Mg, and K. Volatile organic compound 

emissions indicated a maximum for ehtyne, propene, ethane, benzene, toluene, m/pxylenes, nonane and 1,3-butadiene. Although contributions of particle and gaseous 

pollutants from the CDG Airports were found to be substantial, the airport maximums 

were lower than those observed in its vicinities and in the city of Paris during the same 

time period. 

In a recent field campaign conducted in the spring/summer of 2008, Hu et al. 

(2009) measured real-time air pollutant concentrations downwind of Santa Monica 

Airport, a GA airport operated for private aircraft and corporate jets in Los 

Angeles County, California. Aircraft operations resulted in study average UFP levels that 

were elevated by factors of 10 and 2.5 at 100 and 660 m downwind of the runway, 

respectively, over background concentrations. These elevated UFP concentrations were 

mostly associated with jet departures, but also with jet taxi and idle, and operations of 

propeller aircrafts. Conversely, aircraft emissions did not appreciably elevate average 

levels of BC and p-PAHs, although spikes in the concentration of these pollutants were 

commonly associated with jet take-offs. Jet departures resulted in peak 1-min average 

concentrations of up to 2.2 × 106

 #/cm3, 440 ng/m3, and 30 μg/m3 for UFPs, p-PAH, and 

BC, respectively, 100 m downwind of the take-off area. These peak levels were elevated 

by factors of 440, 90, and 100 compared to the corresponding background concentrations. 

CURRENT STUDY ON GENERAL AVATION 

Between November 2005 and February 2007 AQMD conducted a series of field 

campaigns aimed to study the air quality in the communities around the Van Nuys 

Airport (VNA) and Santa Monica Municipal Airport (SMO). The concentrations of 

several gaseous and particle pollutants (i.e. PM, BC, OC, VOCs, lead and other trace 

elements, VOCs and carbonyls) and some of their physical and chemical characteristics 
(e.g. number of UFPs) were measured using real-time and time-integrated instruments at 

multiple monitoring stations set-up inside and at different distances from the airports 

perimeters. The average concentrations of the measured chemical species were compared 

to the corresponding South Coast Air Basin averages and to values obtained at two 

additional concurrent monitoring sites located in Central Los Angeles and in Burbank, 

CA. The resulting data were analyzed to determine if one or both of the study areas 

showed ambient air toxic concentration gradients that can be attributed to aircraft 

emissions/airport activities and/or to other potential sources of air pollution such as 

roadway emissions. 

Launched as part of the U.S. EPA Community Scale Air Toxics Grant, the main 

objectives of this study are a) to characterize the air toxics levels in the communities 

around SMO and VNA, b) to determine the potential impact of airport emissions on 

measured pollutant levels, c) to establish if airport-related emissions are distinguishable 

from those of other potential sources (e.g. nearby traffic), and d) to provide baseline data 

for future studies. Background information about the two airports studied during this field 

campaign is reported below. 

The Van Nuys Airport (VNA)

Located in the San Fernando Valley area in the city of Los Angeles, California, 

VNA (Figure 1) is a public airport used by private, chartered, and small commercial 

aircraft (no commercial airlines fly into this airport). Owned and operated by Los 

Angeles World Airports (LAWA), VNA is one of the busiest GA airports in the world 

with around 450,000 takeoffs and landings annually (2005). With two parallel runways, 

this airport handled around 1,200 and 1,100 operations per day in 2005 and 2006, 

respectively. By comparison, LAX (with 4 runways and a large amount of commercial 

traffic) has about 1,700 operations/day. Most of the news helicopters used in the Los 

Angeles area are based at VNA. With 725 acres, this airport is surrounded by more open 

non-residential areas compared to SMO. 

Figure 1 A current aerial view of the Van Nuys Airport 

6 
The Santa Monica Municipal Airport (SMO)

Located in the heart of the residential community of Santa Monica, California, the 

airport is around 9 miles north-west of LAX, and approximately 23 miles south-west of 

VNA. The Douglas Aircraft Company began to use SMO (Figure 2) to test and fly 

aircraft in 1922. By 1924, production was ramped up to 24/7 with the number of 

employees increasing into the thousands. A large number of employees working in 

aircraft manufacturing needed housing and, consequently, the City of Santa Monica and 

the Los Angeles County designated areas immediately adjacent to the airport for 

residential use. Santa Monica Airport handles an average of about 300 operations per day 

(2009 data) and annual jet air traffic has increased from about 1,000 in 1984 to almost 

14,000 in 2009, mostly due to the ease of access and the increased fees associated with 

fewer access slots at LAX. Total aircraft operations in 2009 numbered 111,688 with 85% 

propeller, 13% jet, and 2% helicopters. In order to minimize the noise and pollution 

impact on the residential area nearby, the city of Santa Monica has strict ordinances that 

prohibit take-offs between the hours of 11pm and 7am on weekdays, and between 11pm 

and 8am on weekends. The lack of a buffer zone separating the airport from residences 

and odor and/or noise complaints by people living in nearby community have raised 

concerns about possible health effects from exposure to gaseous and particle pollutants 

emitted from the airport areas. 

Figure 2 A current aerial view of the Santa Monica Airport 

METHODS 

MONITORING SITES AT THE VAN NUYS AIRPORT 

The airport air quality study work plan included a series of “fully” and “partially” 

instrumented sampling sites (Figure 3). The “fully” instrumented stations (i.e. VOR, Golf 

Course and Holmes School) were set-up at both ends of the runways and in nearby 

communities under the flight path, and were equipped with sequential VOC samplers 

(Xontec® 924 multi-canister VOC sampler), sequential carbonyl samplers (Xontec® 924 

Sampler), total suspended particle (TSP) samplers for lead, speciated PM2.5 samplers 

(Met One® SASS Sampler), continuous CO analyzers, and UFP counters (Condensation 

7 
Particle Counters, or CPCs; TSI® Model 3020 and Model 3781). The “partially” 

instrumented sampling sites (where only a TSP lead sampler and a CO sensor were 

operated) were located on both sides of the runways (i.e. Maintenance Yard and National 

Guard) and at a local elementary school (Cohasset School station). On July 2006, the Air 

National Guard station (Site 5 in Figure 3) was upgraded to a “fully” instrumented site. 

The sampling campaign was divided into two intensive periods to study the 

seasonal variations of the studied air pollutants: from November 2005 to March 2006 

(Phase 1) and from July 2006 to September 2006 (Phase 2). All sampling locations were 

chosen upon examination of historical wind patterns collected from the Federal Aviation 

Administration (FAA) meteorological network. 

Figure 3 Map of the Van Nuys Airport sampling sites. Yellow and blue circles represent 

“fully” and “partially” instrumented sites, respectively (see text for details)

4

3

5

6

2

1

Site # Location 

1 Golf Course 

2 VOR Site 

3 Maintenance Yard 

4 Holmes School 

5 National Guard 

6 Cohasset School 

8 
9 

Van Nuys Airport Sampling Locations

Site 1: Golf Course (Executive Golf Course Service Yard site) 

Address: 16235 Gilmore St., Van Nuys, California 

This monitoring site was located at a Golf Course maintenance facility, 

about 700 m south of the airport and directly under the airport’s fixed 

wing traffic paths. Carbon monoxide, TSP for lead, speciated PM2.5, 

carbonyls, air toxics (in both the particle and the gaseous phases) and 

particle number concentration were collected/measured at this site. 

Site 2: VOR (VHF Omnidirectional Range site) 

Address: 8300 Hayvenhurst Place, Van Nuys, California 

Set-up near the VHF Omnidirectional Range (VOR) navigation system, on 

the strip of land separating Hayvenhurst Ave. from Hayvenhurst Place, 

this station was situated just north of the airport, and sat directly under the 

airport’s fixed wing traffic path. Here sampling consisted of CO, TSP for 

lead, speciated PM2.5, carbonyls, air toxics (in both the particle and the 

gaseous phases) and particle number concentration. 

Site 3: Maintenance Yard 

Address: 7701 Sophia Ave., Van Nuys, California 

This site was operated east of the runway and within the airport facilities 

maintenance complex adjacent to the Tarmac. Here sampling consisted of 

TSP for lead and CO. 

Site 4: Holmes School (Holmes Middle School site) 

 Address: 9351 Paso Robles Ave., Los Angeles, California 

This monitoring site was set-up in the teacher’s parking lot on the southeast corner of the school complex, and near the intersection between 

Prairie Street and Paso Robles Ave. The school itself is approximately 

2,400 m north-west of the airport and, although it was more than 1,000 m 

from the extended centerline of the runway, airplanes were observed 

directly over the school on several occasions. Here sampling consisted of 

CO, TSP for lead, speciated PM2.5, carbonyls, air toxics (in both the 

particle and the gaseous phases) and particle number concentration. The 

first sampling session at the school was from December 2005 to February 

2006. The second monitoring period started in July 2006 and it was 

stopped on 8/11/2006 because of a construction project at the school. 

Site 5: National Guard (Air National Guard Site) 

Address: Van Nuys Airport, Van Nuys, California 
10 

Located next to building No. 105 at the unused Air National Guard 

facility, this site was set-up within the north-west perimeter of the airport 

complex and perpendicular to the centerline of the runway. Here sampling 

consisted of TSP for lead, and CO (Dräger personal monitor) during Phase 

1. This monitoring location was upgraded to a “fully” instrumented site 

upon closure of the Holmes Middle School station in August 2006, at 

which point sampling consisted of CO, TSP for lead, speciated PM2.5, 

carbonyl, air toxics (in both the particle and the gaseous phases) and 

particle number concentration. 

Site 6: Cohasset School (Cohasset Street Elementary School) 

Address: 15810 Saticoy Street, Van Nuys, California 

This monitoring station was operated on the roof of classroom 26, on the 

south-east perimeter of the school campus, and approximately 900 m east 

of the airport. Sampling at this site consisted of TSP for lead and CO.

MONITORING SITES AT THE SANTA MONICA AIRPORT 

Similar to VNA, the airport air quality study work plan included a series of 

“fully” and “partially” instrumented sites (Figure 4). The stations were located close to 

the airport runway (West and East Tarmac sites), in the back yard of a private residence 

downwind of the airport (Ernst Residence site), at an elementary school further away 

from the SMO area (Richland School station), and at a park upwind of the airport 

(Marine Park site). These “fully” instrumented sites were equipped with sequential VOC 

samplers (Xontec® 924 multi-canister VOC sampler), carbonyl samplers (Xontec® 924 

Sampler), TSP samplers for lead, speciated PM2.5 samplers (Met One® SASS Sampler), 

continuous CO analyzers, and UFP counters (TSI® Model 3020 and Model 3781). The 

“partially” instrumented sampling stations (i.e. Maintenance Facility and Walgrove 

School), were set-up on opposite sides of the airport and the centerline of the runway. 

Only a TSP lead sampler and a CO sensor were run at these sites. 

The sampling campaign was divided into two intensive periods to study the 

seasonal variations of the studied air pollutants: from April 2006 to July 2006 (Phase 1) 

and from October 2006 to February 2007 (Phase 2). All sampling locations were chosen 

upon examination of historical wind patterns collected from the FAA meteorological 

network. 
Figure 4 Map of the Santa Monica Airport sampling sites. Yellow and blue circles 

represent “fully” and “partially” instrumented sites, respectively (see text for details) 

7

5

6

1

2 3

4

11 

Site # Location 

1 West Tarmac 

2 East Tarmac 

3 Ernst Residence 

4 Richland School 

5 Maintenance Facility 

6 Walgrove School 

7 Marine Park 

Santa Monica Airport Sampling Locations

Site 1: West Tarmac 

 Address: Santa Monica Airport 

 This monitoring site was located in a field west of the runway, at the same 

elevation as the runway and within the south-west perimeter of the airport. 

Here sampling consisted of CO, TSP for lead, speciated PM2.5, carbonyls, 

air toxics (both in the particle and in the gaseous phases) and particle 

number concentration. 

Site 2: East Tarmac 

 Address: Santa Monica Airport 

 This station was set-up approximately 30 to 40 m west of the end of the 

runway, on the north-east perimeter of the airport and in very close 

proximity to the blast-fence. During Phase 1 sampling was limited due to 

lack of available power and consisted of TSP for lead (using battery 

operated samplers) and gaseous air toxics (collected once every six days). 

During the second phase of the study, SMO personnel provided power to 

the site and sample collection was upgraded to include continuous particle 

count measurements, three 8-hr VOC samples per day (i.e. 00:00 to 08:00, 

08:00 to 16:00, and 16:00 to 00:00), and speciated PM2.5. 
12 

Site 3: Ernst Residence 

Address: 12130 Sardis Ave., Los Angeles, CA 

Set-up in the back yard of a private residence, this site was directly under 

the fixed wing arrival/departure route. The residence (and the surrounding 

neighborhood) sits at a lower elevation than the airport and is 

approximately 100 m northeast of the end of the runway. Sampling 

consisted of CO, TSP for lead, speciated PM2.5, carbonyls, air toxics (in 

both the particle and the gaseous phases) and particle count. 

Site 4: Richland School (Richland Elementary School site) 

 Address: 11562 Richland Ave., Los Angeles, CA 

 This monitoring station was operated in the teacher’s parking lot, close to 

the extended centerline of the runway. The school is less than 1,000 m 

northeast of the airport, and located at a lower elevation than SMO. At this 

location sampling consisted of CO, TSP for lead, speciated PM2.5, 

carbonyls, air toxics (in both the particle and the gaseous phases) and 

particle number concentration. 

Site 5: Maintenance Facility (Airport Maintenance Facility site) 

 Address: Santa Monica Airport 

 Set-up next to the airport facilities maintenance building, which is located 

on the Tarmac, this station was less than 150 m north of the runway. 

Sampling consisted of TSP for lead and CO. 

Site 6: Walgrove School (Walgrove Elementary School site) 

 Address: 1630 Walgrove Ave., Los Angeles, CA 

 This monitoring site was located on the roof of one of the classrooms on 

the north perimeter of the campus and approximately 600 m south of 

SMO. Sampling consisted of TSP for lead and CO. 

Site 7: Marine Park 

 Address: 1406 Marine Street; Santa Monica, CA 

 This station was set-up 1,000 m south-west of SMO, next to several tennis 

courts and directly under the fixed wing arrival/departure flight path. The 

park (and the surrounding neighborhood) is at a slightly lower elevation 

than the airport. Sampling at this site consisted of CO, TSP for lead, 

speciated PM2.5, carbonyls, air toxics (in both the particle and the gaseous 

phases) and particle number concentration. 
13 

MEASURED POLLUTANTS 

Table 1 lists the targeted air toxics measured at VNA and at SMO. Previous work 

has shown that these species are among the most significant contributors to health risks 

related to exposure to air toxics in the South Coast Air Basin (MATES III report). The air 

toxics data have been complemented by the additional measurements of OC, EC, PM2.5

and ultrafine particle count. Information about wind speed and wind direction for the 

entire duration of the study has been obtained from the local airport authorities. 

Table 1 List of the most relevant particle and gaseous species monitored during this 

study at both the Van Nuys and Santa Monica Airports 

Target Pollutants 

PM2.5 mass 1,3-Butadiene Perchloroethylene 

Organic Carbon (OC) Methylene chloride Formaldehyde 

Elemental Carbon (EC) Chloroform Acetaldehyde 

Trace Elements (e.g. Lead) Benzene Acetone 

Ultrafine Particles (UFP) Count Carbon Tetrachloride Methyl Ethyl Ketone 

Carbon Monoxide (CO) Trichloroethene 

Vinyl Chloride Toluene 

SAMPLING SCHEDULE 

All 24-hr integrated PM2.5 samples were collected on a one-in-three day basis. 

High volume total suspended particulate samples for lead analyses could not be collected 

at the East Tarmac site during Phase 1 because of a lack of electrical power, and a low 

volume sampler with a smaller power requirement (BGI® Model PQ100 Sampler; 

Waltham, Massachusetts) was used instead. Three 8-hr VOC samples (i.e. 00:00 to 08:00, 

08:00 to 16:00, and 16:00 to 00:00) were collected every third day at the “fully” 

instrumented monitoring locations. This schedule is identical to that used by AQMD 

during the third Multiple Air Toxics Exposure Study (MATES III) and the typical U.S. 

EPA schedule for ambient PM sampling. One minute data from all continuous 

instruments (i.e. CO and ultrafine particle measurements) were recorded on a data logger 

and averaged to hourly concentrations to facilitate comparison among sites. The data files 

were periodically downloaded to a laptop computer and transferred to the AQMD’s 

central database. A summary of the sampling schedule for VNA and for SMO is shown 

below (Table 2). 
14 

Table 2 Sampling schedule for the Van Nuys and Santa Monica Airports 

Van Nuys Airport Santa Monica Airport 

November 2005 – Site set-up March 2006 – Site set-up 

December 2005 – Sampling start date 

(Phase 1) 

April 2006 – Sampling start date 

(Phase 1) 

March 2006 – Sampling end date July 2006 – Sampling end date 

July 2006 – Site set-up November 2006 – Site set-up 

August 2006 – Sampling start date 

(Phase 2) 

December 2006 – Sampling start date 

(Phase 2) 

November 2006 – End of the 

sampling campaign 

March 2007 – End of the sampling campaign 

LABORATORY ANALYSIS 

Laboratory analysis of the collected samples was conducted by the AQMD 

laboratory. A variety of analytical methods were used to measure the concentrations of 

the targeted chemical compounds (Table 3). 

Table 3 Sampling and analysis methods 

Ambient 

Species 

Sampling 

Method Analysis Method 

Volatile 

Organic 

Compounds 

Silica-Lined 

Canisters 

Gas Chromatography-Mass Spectrometry (GCMS) with automated pre-concentration 

Carbonyls DNPH Cartridge Solvent recovery and subsequent analysis via high 

pressure liquid chromatography (HPLC) 

Carbon 

Monoxide 

Continuous 

Analyzers 

Infrared radiation absorption using gas filter 

correlation 

Lead TSP Samplers Inductively Coupled Plasma Mass Spectrometry 

(ICP-MS) 

Ultrafine 

Particles 

CPC Particle 

Counter 

Continuous particle counts via photo detection of 

light scattering from particles 

PM2.5 Mass PM2.5 Speciation 

Samplers 

PM2.5 Mass determined using analytical 

microbalance 

PM2.5

Metals 

PM2.5 Speciation 

Samplers 

Metals determined by Energy Dispersive X-ray 

Fluorescence Spectrometry (EDXRF) & ICP-MS 

Organic and 

Elemental 

Carbon 

PM2.5 Speciation

 Samplers 

Sections of the PM filter were removed and 

analyzed using a thermal-optical carbon analyzer 

(IMPROVE method) 
15 

Volatile organic compounds were measured from air samples collected in silicalined 6-liter canisters connected to Xontec® 910/912 multi-canister samplers. In addition 

to integrated 24-hr canister samples, VOCs were also collected at 8-hr intervals (i.e. 

00:00 to 08:00, 08:00 to 16:00, and 16:00 to 00:00) to get some insight into the diurnal 

variation of this compound class. VOCs were identified and measured using a Gas 

Chromatograph-Mass Spectrometer (GC/MS). A modified EPA TO-15 method was used 

to collect and analyze all VOC samples. 

Carbonyl compounds were sampled by drawing air through a DNPH (2, 4-

Dinitrophenylhedrazine) cartridge attached to Xontec® 924 samplers; carbonyls undergo 

derivatization upon contact with DNPH. The derivatives were extracted using acetonitrile 

and analyzed using Waters® High Pressure Liquid Chromatography (HPLC) in 

accordance with U.S. EPA method TO-11. The HPLC system employed for the analysis 

of these samples consists of a Waters® 2690 separation module and a Waters® 996 

Photodiode Array Detector. 

At all “fully” instrumented sites, CO was continuously monitored in accordance 

with U.S. EPA equivalent methods criteria using CO Analyzers (Dasibi® 3008 model) 

that operate on the principle of infrared radiation absorption. Personal CO monitors, 

consisting of a CO detector tube attached to a small air pump (Dräger® Personal CO 

Monitors), were used at the “partially” instrumented stations. All sampling probes met 

U.S. EPA criteria for CO sampling. Data were stored on electronic data recorders, 

downloaded on a laptop computer, and transferred to AQMD’s air quality database. 

The concentrations of lead and beryllium were measured on total suspended 

particulate (TSP) samples collected on glass fiber filters using high volume samplers 

(Graseby/Anderson TSP Sampler). The glass fiber filters were extracted with acid and 

analyzed using Inductively Coupled Plasma Mass Spectrometer (ICP-MS; Leco®

Renaissance Time of Flight). 

The concentration of ultrafine particles at VNA (Phases 1 and 2) and at SMO 

(Phase 1 only) was measured continuously by mean of butanol-based condensation 

particle counters (CPCs; TSI® Model 3070). The CPC uses a laser photo diode to flash 

light on the particles that have been supersaturated and grown to detectable sizes with nbutyl alcohol. A photo detector is then used to count the particles in the sample stream. 

The sample inlet probe uses a PM2.5 sharp cut cyclone to eliminate particles larger than 

2.5 μm in diameter. Particle counts were recorded on the same electronic data recorders 

that also stored the CO data. Because the term of the loan for the butanol-based CPCs 

used during the first phase of the Santa Monica field campaign (April–July, 2006) 

expired at the end of September 2006, water-based CPCs (TSI® Model 3781) were 

purchased by AQMD and used instead during the second part of the campaign in Santa 

Monica (October 2006–February 2007). This newer model utilizes water instead of 

butanol to reach supersaturation conditions and grow particles, eliminating the 

characteristic strong odor associated with the Model 3070. 

Integrated 24-hr PM2.5 samples were collected on quartz or teflon filters using 

SASS PM2.5 speciation samplers (Met One® SASS Speciation Sampler), and analyzed 

for: gravimetric mass (using an analytical micro-balance; Sartorus® MC-5), trace 

elemements, OC and EC. Metal analysis of particulate samples was performed using a 

methodology based on IO-3 (Compendium of Methods for Inorganic Air Pollutants) 
16 

implementing a combination of energy dispersive X-ray fluorescence (PANalytical 

Epsilon 5® Energy Dispersive X-Ray Fluorescence Spectrometer), and inductively 

coupled plasma mass spectrometry (Leco® ICP-MS). 

Carbon analysis for the determination of OC and EC was performed on small 

circular disks taken from the loaded PM2.5 quartz fiber filter samples. These disks were 

placed inside a heated furnace of a Thermal/Optical Carbon Analyzer (Desert Research 

Institute, Model 2001) one at the time and subjected to a programmed, step-wise 

temperature increase while helium gas (He) with varying amounts of oxygen was passed 

over the sample. This method (based on the IMPROVE protocol) uses a laser beam to 

monitor and correct, when necessary, the degree of oxidation or carbonization (pyrolysis) 

that occurs during the analysis. 

RESULTS AND DISCUSSION 

The data collected at VNA and at SMO were examined for upwind/downwind 

differences, concentration gradients, evaluated against measurements collected at 

companion AQMD sites (located in downtown Central Los Angeles and in Burbank, CA) 

and compared to the corresponding South Coast Air Basin averages (when available). 

Ultrafine particle count measurements were not taken elsewhere in the Basin and, thus, 

UFP number concentrations at the study sites were compared to one another to assess 

spatial and temporal variabilities. 

METEOROLOGY 

Van Nuys Airport

The wind patterns at the Van Nuys Airport are influenced by the orientation of the 

San Fernando Valley, the surrounding mountain ranges, and the synoptic weather 

systems which pass over Southern California. Wind conditions during Phase 1 

(November 2005-March 2006) and Phase 2 (July-September 2006) of this study are 

typical for this location and the surrounding areas in the San Fernando Valley (e.g. 

Burbank) (Figure 5). In particular, winds around the Van Nuys Airport are influenced by 

a predominant on-shore flow during the day and a lighter off-shore flow at night. This 

land-sea breeze effect dominates the Basin for most of the year. During the winter 

months, north and north-northwest winds are more prevalent and stronger than at other 

times of the year (Figure 5a). Five to ten times a year, normally in the winter months, 

high pressure systems build over the desert plateaus of Nevada and Utah spreading 

southward into the Mojave Desert. The clockwise circulation around these high pressure 

systems can produce a warm, intense north-east wind known locally as Santa Ana winds. 

Santa Ana winds can last from a few hours to several days. The wintertime is the wettest 

season of the year in the Basin and the heaviest precipitation typically occur in February. 

During Phase 2 of this study, the predominant wind flow at the Van Nuys Airport 

was from south-southeast (Figure 5b), although all wind directions are represented in 

varying amounts throughout the year. During summer, atmospheric conditions are more 

consistent when the dominant features influencing winds are strong temperature gradients 

caused by heating over the deserts and the cold waters along the coast. The July through 
September wind rose has features that are representative of the San Fernando Valley 

during a transitional summer to fall climatology. At this time of year, predominant winds 

correspond more closely with south to south-east flows which dominate throughout the 

year. 

Figure 5 Average wind speed and direction at the Van Nuys Airport during a) Phase 1 

(November 2005 - March 2006) and b) Phase 2 (July - September, 2006) 

17 

00

2700 900

1800

00

2700 900

1800

00

2700 900

1800

00

2700 900

1800

a) b)

Wind Speed (mph)

Santa Monica Airport

At this location winds were monitored from April through July 2006 (Phase 1) 

and between October 2006 and February 2007 (Phase 2). Wind rose charts for these time 

periods show the presence of a distinct daytime sea breeze, characteristic of beach 

communities in the South Coast Air Basin (Figure 6). During the spring and summer 

months, winds were predominantly from the west-southwest and southwest (Figure 6a). 

In addition to this strong onshore see breeze, the fall and winter periods were 

characterized by winds coming from all directions (Figure 6b). It is worth noting that 

strong north winds are probably indicating that Santa Ana offshore wind conditions were 

present occasionally. 

Figure 6 Average wind speed and direction at the Santa Monica Airport during a) Phase 

1 (April - July, 2006) and b) Phase 2 (October 2006 - February 2007)

00

2700 900

1800

00

2700 900

1800

00

2700 900

1800

00

2700 900

1800

a) b)

Wind Speed (mph)
18 

LEAD

Van Nuys Airport

TSP lead concentrations collected at all six monitoring stations and during both 

phases of the study were examined for spatial and seasonal patterns, and the results have 

been summarized in Table 4 and Figure 7. The highest average and median lead levels 

(26.1 and 24.4 ng/m3, respectively) during Phase 1 (November 2005-March 2006) were 

measured at the Maintenance Yard site, in close proximity to the east side of the runway 

and within the airport fence-line, and were approximately 3 times higher than the lowest 

average lead concentration (8.45 ng/m3

; measured at the Holmes School site) (Figure 7a). 

Higher increases over typical background concentrations are likely to occur on smaller 

time scales (1-min to 1-hr), especially during periods of intense traffic activity when 

piston driven aircraft are taking-off or landing. A non-parametric one-way Analysis of 

Variance (ANOVA) on ranks revealed that the median lead concentration at the 

Maintenance Yard site is significantly higher (p<0.05) than the corresponding median 

levels observed at all other airport sites and in the South Coast Basin (11.0 ng/m3

). The 

median lead concentrations at the Cohasset School (17.3 ng/m3), at the VOR site (12.0 

ng/m3

), and at the National Guard site (12.8 ng/m3) were also higher than the typical 

median value for the South Coast Basin. 

Overall, our data suggest that the lead concentration gradient at VNA during 

Phase 1 reflect the distance of the six monitoring sites from the runway area, probably 

because of lead emissions from piston driven aircraft operations including idling, takeoff, landing and re-fueling. As explained in a previous paragraph, most aircraft operation 

at GA airports are powered by piston engines and fueled by Avgas, which is 

characterized by a higher volatility and lead content than regular jet fuel. These results 

are in line with those obtained at the Buttonville Airport near Toronto in 2000 (Airborne 

Particulate Matter, Lead and Manganese at Buttonville Airport; prepared by Conor 

Pacific Environmental Technologies Inc. in 2000), where the average lead concentration 

in 24-hr PM10 air samples collected at four different sites near (15 to 50 m) the runway 

was 30 ng/m3

, a value four times higher than that measured at a background station. The 

Buttonville Airport averages about 22,000 aircraft movements per month, many of which 

are small aircraft using aviation gas containing lead, and it is fairly comparable to VNA 

in terms of size and traffic activity (VNA averages about 33,000 per month). 

During the second part of the study (Phase 2; July-September 2006), the overall 

lead concentrations at all sites were substantially smaller than during Phase 1 (Figure 7b), 

with average values between 3.88 and 7.11 ng/m3

 (measured at the Holmes School and at 

the Cohasset School, respectively). A non-parametric one way ANOVA on ranks 

indicated that there is no statistically significant difference among the median lead 

concentrations across all monitored sites (p > 0.05). It is possible that these substantially 

lower concentrations observed in the warmer months are related to seasonal differences 

in airport practices and traffic volume or, most likely, in meteorological conditions. 

Generally, in the late fall and winter light winds result in reduced ventilation, and late 

night/early morning inversions contribute to increasing the surface-level concentrations 

of those pollutants that are emitted from ground-level sources. During the summertime 

months, stronger land breeze/sea breeze circulation and increased insulation results in 
higher wind speeds, increased vertical atmospheric dispersion and, subsequently, reduced 

ambient concentrations. 

Figure 7 Box plots showing the median and mean lead concentrations in total suspended 

particles (black and red lines within each box, respectively) (ng/m3) measured at the Van 

Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Representative lead levels for the South Coast Basin are also reported 

for comparison. Data collected during Phase 2 have been magnified on the top right panel 

to facilitate a comparison among sites 

Mean

Median

75 %

25 %

90 %

10 %

5 %

95 %

Mean

Median

75 %

25 %

90 %

10 %

5 %

95 %

Interestingly, a revised airport-specific lead inventory recently released by EPA in 

2008 (Lead Emissions from the Use of Leaded Aviation Gasoline in the United States, 

prepared by the U.S. EPA) showed that in 2002 lead emissions from landing and take-off 

activities of piston-engine aircraft at the Van Nuys Airport amounted to 1,256 Kg (the 

highest recorded value in the U.S. for that year). It should be noted that the sum of lead 

emissions at the 3,413 airport facilities listed in this EPA document was estimated to be 

282 tons, or about 45% of the total lead emitted nationwide from the use of leaded Avgas. 

The sources that are most likely to account for the remaining 55% include a) over 16,000 

airport facilities where leaded Avgas is used but emissions are not accounted for in the 

national emission inventory, and b) lead emitted outside the landing and take-off cycle 

(airport-specific lead emissions estimates account only for the lead emitted during 

taxi/idle-out, takeoff, climb-out, approach, and taxi/idle-in and do not account for lead 

emitted during cruise). 

19 
20 

Finally, as of October 2008 the U.S. Environmental Protection Agency 

strengthened the National Ambient Air Quality Standard (NAAQS) for lead, lowering it 

from 1500 ng/m3 (quarterly average) to a more stringent 150 ng/m3

 (rolling 3-month 

average). In this respect, none of the concentrations measured at the Van Nuys Airport 

between November 2005 and September 2006 were close to or above the current 

NAAQS. 

Table 4 Average and median lead concentrations in total suspended particles (ng/m3

) at 

the Van Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid samples (Valid N) have also been reported along with 

representative lead data for the South Coast Basin (in red)

Golf 

Course VOR HolmesSchool 

National 

Guard 

Cohasset

School 

Maintenance 

Yard 

South 

Coast

Phase 1 

Average 10.2 15.1 8.45 14.5 18.6 26.1 12.3 

Median 10.1 12.0 6.52 12.8 17.3 24.4 11.0 

SD 5.06 11.5 6.1 9.26 13.3 16.7 7.12 

Min 1.45 1.51 1.55 1.68 0.95 0.10 0.93 

Max 20.7 40.5 21.9 30.5 64.7 83.7 45.9 

Valid N 30 31 33 33 29 33 180 

Phase 2 

Average 4.51 7.85 3.88 6.31 7.11 5.61 5.92 

Median 4.13 7.06 4.19 5.96 7.64 5.49 4.02 

SD 1.84 2.60 1.54 2.59 2.40 2.49 9.24 

Min 1.81 4.66 2.09 2.49 4.07 2.51 0.75 

Max 10.3 15.7 6.10 13.2 9.07 11.1 89.5 

Valid N 22 19 5 21 4 18 131 

Santa Monica Airport

Figure 8 illustrates the spatial and seasonal variations in lead concentration (TSP) 

at all monitored SMO locations. As reported in Table 5, the highest average and median 

lead levels were measured at the East Tarmac and at the Ernst Residence sites, both 

located north (downwind) of the runway and under the fixed wing arrival route. The 

average and median lead concentrations at all other monitoring sites were always slightly 

lower than the correspondent values for the South Coast Basin. The results of a one-way 

ANOVA on ranks revealed that the median lead levels at the East Tarmac and Ernst 

Residence sites were significantly (p<0.05) higher than those at the other monitored 

locations throughout the entire duration of the study. 

It is worth noting that the average lead concentrations at the East Tarmac station 

(85.2 and 77.0 ng/m3

, for Phases 1 and 2, respectively) were 14 to 26 times higher than 

the corresponding average background levels at the Marine Park site, and around one half 
the current, more stringent, NAAQS for lead (150 ng/m3

; rolling 3-month average) (Table 

5). Twenty four hour average values close to, or above the current NAAQS for lead were 

recorded at the East Tarmac site in more than one occasion and during both phases of the 

study. The highest recorded 24-hr lead concentration value was 299 ng/m3

 and refers to a 

TSP sample collected at the East Tarmac in Phase 2. These increased values are probably 

related to the close proximity (30-40 m) of this last site to the blast-fence, where planes 

sometimes idle before clearance for take-off, and to the fact that the predominant winds 

(from southwest) are aligned to the runways of the airport and blowing towards the East 

Tarmac station. 

Located around 100 m northeast of the runway and directly under the fixed wing 

arrival route, the Ernst Residence site (where average lead levels were 28.6 and 22.2 

ng/m3

 during Phases 1 and 2, respectively) was also characterized by increased lead 

concentrations with respect to background conditions (average lead values at the Marine 

Park station were 4 to 9 times lower). Unlike what was observed at VNA, the magnitude 

of the lead concentrations measured in Santa Monica was not substantially different 

between Phase 1 and Phase 2 (Figures 8). 

Figure 8 Box plots showing the median and mean lead concentrations in total suspended 

particles (black and red lines within each box, respectively) (ng/m3

) measured at the 

Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 (October 2006 - 

February 2007). The correspondent lead levels for the South Coast Basin have also been 

reported for comparison 

 It is worth mentioning that a revised airport-specific lead inventory released by 

EPA in 2008 (Lead Emissions from the Use of Leaded Aviation Gasoline in the United 

States, prepared by the U.S. EPA) showed that in 2002 lead emissions from landing and 

take-off activities of piston-engine aircraft at SMO were 369 Kg, a value 3.4 times lower 

than that recorded at VNA during the same year, but within the top 2% among the 3,413 

airport facilities considered in this EPA document. 

21 
Overall, our results show that the measured lead concentration at the Santa 

Monica sites increased with decreasing distance from areas where airplanes were idling, 

taking-off and landing. These outcomes are in line with those obtained at the Buttonville 

Airport near Toronto in 2000 (discussed in the previous chapter) and with those from a 

study conducted at the O’Hare International Airport (Chicago, Illinois) in 2000, where 

airport emissions were found to have an impact in the areas adjacent to the airport for 

several key target compounds including lead (Chicago O’Hare Airport Air Toxic 

Monitoring Program; prepared by the Illinois Environmental Protection Agency, Bureau 

of Air, in 2002). 

 

Table 5 Average and median lead concentrations in total suspended particles (ng/m3

) at 

the Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 (October 2006 

- February 2007). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid samples (Valid N) have also been reported along with 

representative lead data for the South Coast Basin (in red)

ND = non detected 

Walgrove 

School 

Richland 

School 

Marine 

Park 

Maintenance 

Facility 

Ernst 

Residence

East 

Tarmac 

West 

Tarmac

South 

Coast 

Phase 1

Average 3.38 4.50 3.30 3.66 28.6 85.2 4.58 9.47 

Median 2.66 4.00 2.76 2.69 25.3 83.5 4.07 8.86 

SD 2.35 3.57 2.17 3.20 14.1 33.0 4.18 3.55 

Min 0.10 0.10 0.10 0.10 1.59 27.0 0.10 5.19 

Max 9.58 14.7 8.72 13.5 60.1 135.0 17.7 15.0 

Valid N 29 37 30 32 20 12 31 13 

Phase 2 

Average 5.79 7.59 5.50 7.68 22.2 77.0 9.05 13.1 

Median 5.97 6.92 5.95 6.52 17.1 67.0 7.14 12.7 

SD 2.66 5.32 2.48 4.92 16.6 68.6 6.84 4.05 

Min ND ND 0.10 1.78 3.99 0.10 2.01 4.88 

Max 9.22 30.1 9.86 21.3 70.1 299 37.7 19.3 

Valid N 25 32 35 25 38 33 32 16 

EAST TARMAC SITE (METHOD COMPARISON) 

During Phase 1 electrical power was not available at the East Tarmac site to 

operate the hi-volume TSP samplers. Therefore, a smaller battery powered low volume 

sampler (BGI® Model PQ100 Sampler; Waltham, Massachusetts) configured to collect 

TSP was deployed instead. In this case, all filter samples were collected on teflon 

substrates at 12 lpm and analyzed for lead using X-Ray Fluorescence (XRF) rather than 

Inductively Coupled Plasma Mass Spectrometry (ICP-MS). PM2.5 speciated samples were 

also collected at the Ernst Residence, Marine Park and Richland School stations during 

the entire duration of the study and analyzed for lead using XRF. Small quantities of all 

22 
loaded teflon filters were also digested with acid, and the extracts analyzed by ICP-MS to 

compare the two methods. Although the lead concentrations obtained by XRF may be 

biased about 25 ng/m3

 high compared to those from ICP-MS analyses, an excellent 

agreement (R2

 = 0.97) was found between the results of these two analytical methods 

(Figure 9). It is possible that the teflon filter matrix may require a more rigorous digestion 

step than the glass fiber filter typically used for ICP-MS, since teflon is well known for 

its resistance to aqueous wetting. 

Figure 9 Comparison between lead concentrations obtained from XRF and ICP-MS 

analyses of selected TSP samples collected at the East Tarmac site (Santa Monica 

Airport) during Phase 1 

Lead data from the analysis of samples collected using the PM2.5 speciation 

samplers show a spatial pattern across the four monitored locations (i.e. East Tarmac, 

Ernst Residence, Marine Park and Richland School stations) (Figure 10) similar to that 

observed from the TSP lead data (Figure 8). The average and median lead concentrations 

in fine particles were elevated above the typical South Coast Basin levels at both the 

Ernst Residence site (during both phases) and at the East Tarmac station (during Phase 2 

only; PM2.5 samples for lead analysis were not collected at this location during Phase 1). 

This suggests that a relatively high proportion of lead at these two stations was not 

associated with re-suspended material (which would consist of coarser particles primarily 

above 2-5μm in diameter), and may have originated from fresh emissions from aircraft 

idling, landing, or taking-offs, or from other airport-related activities such as re-fueling. 

At all sites Pb(PM2.5) / Pb(TSP) ratios were between 0.83 and 1.48. Values higher than 

one may be due to differences in measurement methods. The average and median lead 

levels measured in PM2.5 particles during the second year of the MATES III study (from 

April 2005 to March 2006) were comparable to the corresponding average concentrations 

observed at the Marine Park station (background site) during both Phases 1 and 2 of this 

23 
study. Overall, our results suggest that aviation gas combustion leads to the formation 

and emission of small primary PM2.5 particles containing lead. 

Figure 10 Box plots showing the median and mean lead concentrations (ng/m3

) in fine 

particulate matter (PM2.5) measured at four monitoring sites of the Santa Monica Airport 

(black and red lines within each box, respectively) during Phase 1 (April - July, 2006) 

and Phase 2 (October 2006 - February 2007). Lead levels for the South Coast Basin 

(same time periods) and at MATES III sites (from April 2005 to March 2006 only) are 

shown for comparison 

VOLATILE ORGANIC COMPOUNDS (VOC) 

The following volatile organic compounds (VOCs) were selected for discussion 

because of their potential importance relative to toxic cancer risk in the South Coast Air 

Basin: 1,3-butadiene, methylene chloride, chloroform, benzene, carbon tetrachloride, 

toluene, and perchloroethylene. Nearly all samples collected at all sites showed vinyl 

chloride and trichloroethene levels at or below their corresponding detection limits. Thus, 

the concentrations of these two volatile species are not discussed in the following 

paragraphs. Averaged 24-hr VOC concentrations were then compared to the 

corresponding daily-averaged levels at two AQMD companion monitoring stations, one 

in Burbank, CA (about 14 mi south-east of VNA) and the other in Central Los Angeles 

(around 14 mi east of SMO). In an effort to get some insight into the daily variations of 

the measured VOCs three 8-hr samples (i.e. 00:00 to 08:00, 08:00 to 16:00, and 16:00 to 

00:00) were collected daily at four sites for VNA [i.e. Golf Course, Holmes School, 

National Guard (Phase 2 only) and VOR] and at five sites for SMO (i.e. Richland School, 

Marine Park, Ernst Residence, East Tarmac and West Tarmac). A detailed discussion of 

important VOC results follows. 

24 
25 

Van Nuys Airport

With the exception of chloroform, the average and median concentrations of 1,3-

butadiene, methylene chloride, benzene, carbon tetrachloride, toluene, and 

perchloroethylene were generally higher during the first phase of the study (November 

2005 – March 2006) (Figures 11a, 11b, and 11c) as compared to the second phase. 

Typically, in the fall/winter months light winds result in reduced ventilation, and late 

night/early morning inversions contribute to increased surface-level concentrations of 

pollutants emitted from ground-level sources. During the summer months, stronger 

land/sea breeze circulation and increased insulation results in higher wind, increased 

vertical atmospheric dispersion and, subsequently, reduced ambient concentrations. A 

similar seasonal variability in the concentration of benzene, 1,3 butadiene, methylene 

chloride and perchloroethylene, with wintertime maximums and summertime minimums, 

was also observed in the South Coast Basin during the MATES II and MATES III studies 

(prepared by AQMD in 2000 and 2008, respectively). 

The spatial distribution of most VOCs did not vary substantially across the two 

sampling periods and, in most cases, the highest concentrations across all Van Nuys 

stations were observed at sites that were closer to busy surface streets and, to a lesser 

extent, to the airport area. For example, the Golf Course station, characterized by 

relatively high VOC levels, was less than 100 m north of Victory Blvd. (a major eastwest arterial road traversing the entire length of the San Fernando Valley) and about 700 

m from the south perimeter of the airport, directly under the airport’s fixed wing traffic 

path. Because the concentration of vehicle-related pollutants decreases exponentially with 

distance from roadways and returns to background levels after only 300 to 2,500 m 

(depending on the type of the pollutant, traffic conditions, time of the day, and local 

meteorology) (Zhu et al., 2002a and 2002b; Hu et al., 2009), it is possible that motorvehicle emissions played a significant role in increasing the measured atmospheric 

concentrations of most VOCs at the Golf Course site. Conversely, the Holmes School 

station, where lower gaseous concentrations were generally observed, was around 2,400 

m north-west of the Van Nuys Airport and at least 300 m away from any major surface 

street. The levels of most volatile species at the VOR and National Guard sites (set-up in 

close proximity and within the airport fence-line, respectively) were mostly between 

those recorded at the Golf Course and at Holmes School monitoring stations. 

The highest VOC concentrations measured at VNA were comparable to those 

observed at an urban site in Burbank (especially during Phase 1; Figure 11), located in 

close proximity to the Ventura Freeway (Route 134), the Golden State Freeway (I-5), and 

several other major and local roads. Overall, our results seem to suggest the concentration 

gradient of most VOCs measured in the VNA area is mostly influenced by proximity to 

mobile sources surrounding the airport’s perimeter. The extent of the contributions of this 

and other pollution sources including aircraft emissions and other airport activities to the 

measured VOC levels cannot be assessed from the available data. 

These outcomes are in line with those obtained from similar studies in other parts 

of the United States. For example, the results from a recent field campaign conducted by 

ENVIRON Corp. at the Teterboro Airport in New Jersey (one of the busiest GA airports 

in the United States) revealed that the concentrations of most VOCs were comparable to 

or lower than those measured in the urban area of Elizabeth (NJ), where the atmospheric 

levels of these volatile pollutants are typically dominated by mobile source emissions 
(Teterboro Airport, New Jersey, Detailed Air Quality Evaluation, Final Report Prepared 

by ENVIRON Corp. in 2008). A comparison between ambient VOC data at the O’Hare 

International Airport (one of the world’s busiest airports) and those representing “typical 

urban” concentrations in the Chicago, Atlanta, Detroit, Houston and Milwaukee 

metropolitan areas led to similar conclusions (Chicago O’Hare Airport Air Toxic 

Monitoring Program; prepared by the Illinois Environmental Protection Agency, Bureau 

of Air, in 2002). A summary of all 1,3-butadiene, methylene chloride, chloroform, 

benzene, carbon tetrachloride, toluene, and perchloroethylene data collected at 

VNA can be found in Appendix A. 

Figure 11 Spatial distributions of a) 1,3-butadiene, methylene chloride, and chloroform, 

b) benzene, carbon tetrachloride, and toluene, and c) percholoethylene at 5 monitoring 

sites of the Van Nuys Airport (i.e. Golf Course, Holmes School, VOR, and National 

Guard sites) during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Data collected concurrently at a monitoring station in Burbank are also 

included for comparison 

26 

a) 
b) 

c) 

27 
28 

Santa Monica Airport

With the exception of carbon tetrachloride, the average and median 

concentrations of all VOCs present in substantial amounts in the canister samples 

collected at SMO (namely, 1,3-butadiene, methylene chloride, chloroform, benzene, 

carbon tetrachloride, toluene, perchloroethylene and trichloroethene) were generally 

higher during the fall/winter months (from October 2006 to February 2007; Phase 2) than 

in the spring/summer period (between April 2006 and July 2006; Phase 1). This is 

consistent with typical seasonal changes in local meteorological conditions, and with 

what was observed at the Van Nuys Airport. 

Although the spatial distribution of most volatile species did not vary 

substantially across the 2 sampling periods, it is difficult to discern a consistent 

concentration gradient across the sampling sites (Figures 12a, 12b, and 12c). However, in 

most occasions slightly higher VOC levels were observed at the Richland School, East 

Tarmac, Ernst Residence, and West Tarmac stations, probably because of their relative 

proximity to the Santa Monica freeway (I-10), to several congested surfaces streets and, 

possibly, to the airport area. In particular, the Richland School site (the furthest from 

SMO) was less than 300 m south of the I-10 (a major east-west interstate highway that 

runs east from Santa Monica through Los Angeles), about 600 m west of interstate 405 

(I-405; a heavily traveled north-south thoroughfare known to be one of the busiest 

freeways in the United States), and close to several trafficked surface streets. The East 

Tarmac and Ernst Residence sampling locations were within 100 m from the inner and 

outer edge of the airport fence-line, respectively, in very close proximity to Bundy Dr. 

and National Blvd (two highly trafficked streets adjacent to the north-east side of the 

airport), and about 600-800 m south of the I-10. The West Tarmac site was within the 

southwest perimeter of the airport, less than 100 m from the southern end of the runway, 

but approximately 1,700 m away from the I-10. Lastly, the Marine Park station, where 

the lowest VOC levels were generally measured, was the farthest from the I-10 (more 

than 2,100 m) and possibly too far from the airport perimeter to be influenced by VOCs 

emitted from aircraft operations and other related-activities. 

As observed at VNA, the VOC levels in Santa Monica were generally comparable 

to or lower than those at the companion urban monitoring station (Central Los Angeles, 

in this case) where motor-vehicles emissions dominate the atmospheric levels of most 

primary pollutants. Overall, our results seem to suggest that the VOC levels measured at 

the Santa Monica stations were mostly influenced by their proximity to nearby freeways 

(e.g. the I-10) or local surface streets and, possibly to a lesser degree by their relative 

distance to the airport. However, the contributions of these and other pollution sources to 

the measured VOC levels cannot be assessed from the available data. A summary of all 

1,3-butadiene, methylene chloride, chloroform, benzene, carbon tetrachloride, toluene, 

perchloroethylene and trichloroethene data collected at SMO can be found in Appendix 

A. 
Figure 12 Spatial distributions of a) 1,3-butadiene, methylene chloride, and chloroform, 

b) benzene, carbon tetrachloride, and toluene, and c) trichloroethane and 

perchloroethylene at selected monitoring sites of the Santa Monica Airport (i.e. Richland 

School, Marine Park, Ernst Residence, East Tarmac, West Tarmac sites) during Phase 1 

(April - July, 2006) and Phase 2 (October 2006 - February 2007). Data collected 

concurrently at a monitoring site in Central Los Angeles are also included for comparison 

a) 

29 
30 

b) 

c) 
31 

EIGHT-HOUR VOC 

Van Nuys Airport

In addition to integrated 24-hr canister samples, VOCs were also collected daily 

at 8-hr intervals (i.e. 00:00 to 08:00, 08:00 to 16:00, and 16:00 to 00:00) to examine the 

diurnal variability of this important compound class. Typically, the concentrations of 

most VOCs were higher between 00:00 and 08:00 and, to a lesser extent, from 16:00 and 

00:00, probably because of a decreased mixing height and increased atmospheric stability 

early in the morning and late at night. Interestingly, the percentage contribution of most 

VOCs collected between 00:00 and 08:00 to their corresponding 24-hr average 

concentrations was higher during the summer months (the average for all VOCs and at all 

sites during Phase 2 is 45%) than in the fall/winter period (the corresponding average 

contribution during Phase 1 is 37%). This situation (shown for the VOR site in Figures 

13a and 13b and representative of all other stations at VNA) may be due to more 

persisting inversions throughout the winter days and, perhaps, to seasonal variations in 

airport activities such as increased air traffic in the early mornings of most summer 

months (July – September, 2006). All available 8-hr VOC concentrations and the 

corresponding percentage contributions to their total daily levels have been summarized 

in Appendix A. 
Figure 13 Percentage contribution of volatile organic compounds (VOCs) measured at 

the VOR site during three 8-hr intervals (i.e. 00:00 to 08:00, 08:00 to 16:00, and 16:00 to 

00:00) to the corresponding 24-hr average concentrations. The two panels refer to a) 

Phase 1 (November 2005 - March 2006) and b) Phase 2 (July - September, 2006) data 

0%

20%

40%

60%

80%

100%

1,3-Butadiene

Benzene

Carbon 

Tetrachloride

Chloroform

Methylene Chloride

Perchloroethylene

Toluene

Trichloroethene

% of VOC 

per time period

Van Nuys Airport - VOR Site - Phase 1

00:00 - 08:00

08:00 - 16:00

16:00 - 00:00

0%

20%

40%

60%

80%

100%

1,3-Butadiene

Benzene

Carbon 

Tetrachloride

Chloroform

Methylene Chloride

Perchloroethylene

Toluene

Trichloroethene

% of VOC 

per time period

Van Nuys Airport - VOR Site - Phase 2

00:00 - 08:00

08:00 - 16:00

16:00 - 00:00

b) 

a) 

32 
Santa Monica Airport

As at VNA, three integrated 8-hr canister samples (i.e. 00:00 to 08:00, 08:00 to 

16:00, and 16:00 to 00:00) were collected daily at all Santa Monica sites and analyzed for 

VOCs. Also in this case, the concentrations of most volatile species were higher between 

00:00 and 08:00, and the percentage contribution of most VOCs collected in this time 

frame to their corresponding 24-hr average concentrations was higher during the 

spring/summer months (the average for all VOCs and at all sites during Phase 1 is 49%) 

than in the fall/winter period (the corresponding average contribution during Phase 2 is 

42%). This situation is illustrated for the West Tarmac site in Figures 14a and 14b, and it 

is representative of all other Santa Monica stations. All available 8-hr VOC levels and the 

corresponding percentage contributions to their total daily concentrations have been 

summarized in Appendix A. 

Figure 14 Percentage contribution of volatile organic compounds (VOCs) measured at 

the West Tarmac site during three 8-hr intervals (i.e. 00:00 to 08:00, 08:00 to 16:00, and 

16:00 to 00:00) to the corresponding 24-hr average concentrations. The two panels refer 

to a) Phase 1 (April - July, 2006) and b) Phase 2 (October 2006 - February 2007) data 

0%

20%

40%

60%

80%

100%

1,3-Butadiene

Benzene

Carbon 

Tetrachloride

Chloroform

Methylene 

Chloride

Perchloroethylene

Toluene

Trichloroethene

% of VOC 

per time period

Santa Monica Airport - West Tarmac Site - Phase 1

00:00 - 08:00

08:00 - 16:00

16:00 - 00:00

0%

20%

40%

60%

80%

100%

1,3-Butadiene

Benzene

Carbon 

Tetrachloride

Chloroform

Methylene 

Chloride

Perchloroethylene

Toluene

Trichloroethene

% of VOC 

per time period

Santa Monica Airport - West Tarmac Site - Phase 2

00:00 - 08:00

80:00 - 16:00

16:00 - 00:00

a)

b) 

33 
34 

CARBONYLS 

Van Nuys Airport 

The most abundant carbonyl species present in all canister samples collected at 

VNA were formaldehyde, acetaldehyde, acetone and methyl ethyl ketone (MEK). 

Previous studies conducted on commercial aircraft engines have found formaldehyde and 

acetaldehyde to be the dominant carbonyls in aircraft exhaust emissions (Agrawal et al., 

2008). As for most VOCs, our results seem to suggest that the concentration gradient of 

the majority of carbonyl compounds measured across all Van Nuys sites is influenced by 

proximity to local streets and, to a lesser extent, to the airport area (Figure 15). In 

particular, while the lowest carbonyl levels were observed at the Holmes School station 

(~ 2,400 m from the north-west perimeter of the airport and more than 300 m away from 

any major surface street), higher concentrations of MEK, acetone, acetaldehyde and 

formaldehyde were always detected at the Golf Course, VOR, and National Guard sites 

(closer to more heavily traveled roads and near or within the airport fence-line). 

However, unlike what was observed for most volatile species, the concentrations of all 

carbonyl compounds measured at the urban site in Burbank were generally lower than 

those recorded at the Van Nuys Airport stations (Figure 15). The difference was more 

evident in Phase 2 during the warmer months. More specifically, a non-parametric oneway ANOVA on ranks showed that the median ambient levels of acetone (during Phases 

1 and 2) and those of MEK (during Phase 1 only) in Burbank were significantly lower 

(p< 0.05) than the corresponding concentrations at all other monitoring sites. Although it 

is possible that emissions of certain carbonyls from aircraft and airport operations might 

have increased the ambient concentrations of these air toxics with respect to typical urban 

levels, the extent of the contribution of this and other airport-related sources to the 

carbonyl levels measured at the Van Nuys Airport cannot be assessed from the available 

data. A summary of all formaldehyde, acetaldehyde, acetone and MEK data collected at 

VNA during this study can be found in Appendix A. 
Figure 15 Spatial distributions of formaldehyde, acetaldehyde, acetone, and methyl ethyl 

ketone (MEK) at selected monitoring sites of the Van Nuys Airport (i.e. Golf Course, 

Holmes School, VOR, and National Guard sites) during Phases 1 and 2. Data collected at 

an AQMD monitoring station in Burbank are also included for comparison 

35 
36 

Santa Monica Airport

The average and median concentrations of the most abundant carbonyl 

compounds measured at SMO (formaldehyde, acetaldehyde, acetone and MEK) were 

higher during the fall/winter period (from October 2006 to February 2007; Phase 2) than 

during the spring/summer months (from April 2006 to July 2006; Phase 1) (Figure 16), 

which is consistent with the expected seasonal variations in local meteorological 

conditions. The ambient concentrations of the carbonyls measured at an urban site in 

Central Los Angeles were generally comparable to those recorded at the Santa Monica 

stations. The exception is lower MEK and acetone at the Central Los Angeles site during 

Phase 1, but there is no obvious explanation for this observed difference. Although the 

spatial distribution of most carbonyl species did not vary substantially across the two 

sampling periods, it is difficult to discern a definite concentration gradient across the 

monitoring sites. However, it is worth mentioning that the average and median 

formaldehyde concentration at the Marine Park site (away from the I-10 freeway and 

relatively far from the airport perimeter) were the lowest across all stations monitored 

during Phase 1, and the highest during Phase 2. The reasons for this unexpected seasonal 

difference are not clear, but might be related to one or more localized sources of 

carbonyls around the park area. We cannot exclude that emissions of formaldehyde and 

other carbonyl compounds from aircraft and airport activities might have also contributed 

to increase the concentrations of these pollutants at SMO sites. However, the extent of the 

contribution of this and other potential important sources (e.g. motor-vehicle emissions 

from the I-10 freeway and from other local roadways) to the carbonyl levels measured 

around SMO cannot be assessed from the available data. A summary of all formaldehyde, 

acetaldehyde, acetone and MEK data collected at SMO throughout this study can be 

found in Appendix A. 
Figure 16 Spatial distributions of formaldehyde, acetaldehyde, acetone, and methyl ethyl 

ketone (MEK) at selected monitoring sites of the Santa Monica Airport (i.e. Richland 

School, Marine Park, Ernst Residence, East Tarmac, and West Tarmac sites) during 

Phases 1 and 2. Data collected at an AQMD monitoring station in Central Los Angeles 

are also included for comparison 

37 
PM2.5 MASS, ELEMENTAL AND ORGANIC CARBON 

Van Nuys Airport

Although the average and median levels of PM2.5, OC and EC measured at VNA 

sites were not substantially different across the two phases of the study, a higher 

variability in the atmospheric concentrations of these three particulate pollutants was 

observed during Phase 1 (November 2005 – March 2006), as shown in Figure 17 and in 

Table 6. The spatial distribution of PM2.5 and that of its carbonaceous components did not 

vary substantially across the two sampling periods and, in most cases, it was similar to 

that observed for most VOCs and carbonyl compounds. In particular, the highest average 

concentrations of PM2.5, OC and EC across all Van Nuys stations were measured at 

locations that were closer to the airport (i.e. VOR and National Guard stations) and to 

heavily trafficked surface streets (i.e. Golf Course site), while the lowest levels were 

recorded at the Holmes School site (background), further away from these pollution 

sources. 

Figure 17 Spatial distributions of fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) at selected monitoring sites of the Van Nuys Airport 

(i.e. Golf Course, Holmes School, VOR, and National Guard sites) during Phases 1 and 2. 

Data collected at an AQMD monitoring station in Burbank are also included for 

comparison 

38 
39 

The average and median concentrations of PM2.5, OC and EC at the Golf Course, 

VOR and National Guard stations were elevated by a factor of less than two with respect 

to “background levels”. At Holmes School this is probably due to the fact that these 

measurements refer to integrated 24-hr average samples. More substantial increases in the 

concentrations of EC may occur on shorter time-scales (e.g. minutes to hours) and closer 

to the runway area, especially while airplanes are taking-off. A previous study that 

focused on the chemical and physical analysis of the exhaust from various in-use 

commercial aircraft at two different airports indicated that take-off plumes are 

characterized by substantial increases in black carbon (BC; another indicator, along with 

EC, of combustion particles similar to those emitted from diesel engines) content 

(Herndon et al., 2005). 

A non-parametric one way ANOVA on ranks indicated that during Phase 1 the 

median concentrations of PM2.5 and EC at an urban site in Burbank (20.2 and 3.05 μg/m3

, 

respectively) were significantly higher (p<0.05) than the corresponding levels measured 

at all Van Nuys stations. Similarly, a statistically significant difference (p<0.05) in 

median OC levels was also observed between the Burbank station and the Holmes School 

and VOR sites. Overall, our data do not point to airport operations as the main source of 

the particulate pollutants measured at VNA sites. It is more likely that other local and 

regional sources (e.g. motor-vehicle emissions from nearby traffic and atmospheric 

transport of aged pollutants, respectively) contributed to the observed atmospheric levels 

of fine PM and those of its carbonaceous components. This is consistent with the 

previous observations of the concentration gradients of the gaseous pollutants measured 

at the same locations. None of the seasonal average (or median) PM2.5 values measured at 

VNA sites were higher than the corresponding 2006 annual average in the South Coast 

Basin (20.6 μg/m3

), or the U.S. EPA NAAQS for fine PM (35 μg/m3, expressed as the 3-

year average of the 98th percentile of 24-hr concentrations). 
Table 6 Average and median fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) concentrations (μg/m3

) at the Van Nuys Airport 

stations and at an urban site in Burbank (CA) during Phase 1 (November 2005 - March 

2006) and Phase 2 (July - September, 2006). Minimum (Min) and maximum (Max) 

values, standard deviations (SD), and the total number of valid samples (Valid N) have 

also been included 

Golf 

Course 

Holmes 

School VOR National Guard Burbank 

PM2.5 - Phase 1 

Average 13.9 12.0 14.2 N/A 22.8 

Median 10.6 7.84 12.2 N/A 20.2 

SD 9.87 8.69 9.75 N/A 13.0 

Min 3.51 2.89 2.99 N/A 4.03 

Max 37.4 31.7 34.8 N/A 58.7 

Valid N 32 33 33 N/A 39 

PM2.5 - Phase 2 

Average 14.7 10.8 17.7 16.7 N/A 

Median 13.6 10.9 16.8 17.3 N/A 

SD 4.69 2.70 8.45 4.23 N/A 

Min 7.72 6.48 7.13 10.1 N/A 

Max 24.8 13.6 48.2 26.3 N/A 

Valid N 22 5 22 14 N/A 

OC- Phase 1

Average 9.35 6.03 7.28 N/A 10.4 

Median 9.79 5.00 7.89 N/A 11.0 

SD 4.74 3.38 3.88 N/A 3.75 

Min 1.97 1.72 1.60 N/A 2.89 

Max 19.4 13.4 13.8 N/A 19.6 

Valid N 31 33 33 N/A 39 

OC- Phase 2

Average 7.63 6.49 8.76 8.74 N/A 

Median 7.32 5.30 7.69 7.49 N/A 

SD 3.75 4.72 5.19 4.12 N/A 

Min 2.18 2.11 1.94 4.98 N/A 

Max 19.1 14.4 27.0 17.8 N/A 

Valid N 22 5 22 14 N/A 

EC- Phase 1

Average 1.85 1.51 1.86 N/A 3.07 

Median 1.62 1.33 1.56 N/A 3.05 

SD 1.36 1.18 1.33 N/A 1.48 

Min 0.25 0.03 0.11 N/A 0.43 

Max 5.51 3.93 4.67 N/A 6.18 

Valid N 31 33 33 N/A 39 

EC- Phase 2

Average 1.65 1.21 1.99 1.89 N/A 

Median 1.52 1.20 1.86 1.57 N/A 

SD 0.72 0.88 0.94 0.81 N/A 

Min 0.33 0.44 0.10 0.77 N/A 

Max 3.75 2.62 4.08 4.02 N/A 

Valid N 22 5 22 14 N/A 

40 
Santa Monica Airport 

The average and median PM2.5 mass concentrations at SMO stations showed 

rather low spatial and seasonal variability (from 14.9 to 17.4 μg/m3 during Phase 1, and 

from 14.7 to 17.3 μg/m3

 during Phase 2), and were comparable (or lower) to those 

measured at an urban station in Central Los Angeles (Figure 18 and Table 7). As 

observed in the previous section, this is probably related to the fact that regional transport 

was driving the PM2.5 levels in this area at the time of sampling. None of the 24-hr 

seasonal average (or median) PM2.5 values measured at SMO sites were higher than the 

corresponding 2006 annual average in the South Coast Basin (20.6 μg/m3

). 

Figure 18 Spatial distributions of fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) at selected monitoring sites of the Santa Monica 

Airport (i.e. Richland School, Marine Park, Ernst Residence, East Tarmac, and West 

Tarmac sites) during Phases 1 and 2. Data collected at an AQMD monitoring station in 

Central Los Angeles are also included for comparison 

41 
42 

The spatial distribution of OC and EC did not vary substantially across the two 

sampling periods and, for the most part, it was similar to that observed for VOC and 

carbonyl compounds. In particular, the atmospheric levels of these two carbonaceous 

components seemed to be more variable at sites that were closer to the airport area of 

operation (e.g. East Tarmac and Ernst Residence), and slightly lower average and median 

OC and EC values were generally measured at the Marine Park site (background), away 

from the influence of airport emissions. A non-parametric ANOVA on ranks revealed 

that, with the exception of the median OC level at the Ernst Residence site during Phase 

1, the median ambient levels of OC and EC at the Santa Monica stations were 

significantly lower (p<0.05) than those in Central Los Angeles, both during Phase 1 and 

Phase 2. This might be due to a relatively higher contribution of carbonaceous material 

from motor-vehicles at this urban site in Central Los Angeles. Higher average and 

median concentrations were measured in the colder months (October 2006–February 

2007), which is consistent with more persistent inversions during the fall/winter period. 

As noted in previous sections, the effect of airport activities on EC may be 

observed on a shorter time-scale (e.g. minutes to hours), and previous studies have shown 

sharp increases in EC (or BC) levels during take-off and landing (Herndon et al., 2008; 

Westerdahl et al., 2008; Dodson et al., 2009; Hu et al., 2009). In particular, in the 

summer/spring of 2008 Hu et al. (2009) conducted a four-day field campaign using an 

electric vehicle equipped with fast response instruments to measure real time air pollutant 

concentrations downwind of SMO. They found that aircraft did not appreciably elevate 

the average levels of BC (which supports this study’s results), although spikes in the 

concentration of this and other combustion-related pollutants (i.e. polycyclic aromatic 

hydrocarbons and UFP) were generally observed during jet take-offs and, possibly, 

aircraft arrivals. Specifically, jet departures resulted in 1-min average BC concentrations 

of up to 30 μg/m3

 at a site located 100 m downwind of the takeoff area (in a similar 

geographical location as our Ernst Residence station), a value 100 higher than the 

corresponding summer background level. 
43 

Table 7 Average and median fine particulate matter (PM2.5), organic and elemental 

carbon (OC and EC, respectively) concentrations (μg/m3

) at the Santa Monica Airport 

stations and at an urban site in Central Los Angeles (CA) during Phase 1 (April - July, 

2006) and Phase 2 (October 2006 - March 2007). Minimum (Min) and maximum (Max) 

values, standard deviations (SD), and the total number of valid samples (Valid N) have 

also been included 

 

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac 

Central Los 

Angeles 

PM2.5 - Phase 1 

Average 14.9 15.2 17.4 N/A 15.8 16.9 

Median 15.2 14.4 16.7 N/A 15.8 15.3 

SD 6.76 6.70 5.75 N/A 6.28 9.14 

Min 4.13 4.64 9.18 N/A 4.74 4.71 

Max 35.8 34.8 34.6 N/A 32.5 40.7 

Valid N 35 30 25 N/A 34 28 

PM2.5 - Phase 2 

Average 16.2 18.5 17.3 14.7 16.6 16.8 

Median 13.6 17.1 14.3 12.5 14.8 16.6 

SD 9.20 8.90 9.36 8.81 9.28 6.79 

Min 4.95 9.81 5.07 1.86 3.10 5.63 

Max 49.8 45.4 51.2 41.4 49.6 33.5 

Valid N 43 13 40 29 39 27 

OC- Phase 1

Average 4.78 3.96 5.69 N/A 4.05 6.26 

Median 4.32 3.70 4.48 N/A 3.52 6.07 

SD 2.13 1.60 2.65 N/A 2.49 1.92 

Min 2.09 1.92 2.83 N/A 1.78 2.38 

Max 11.9 11.3 12.3 N/A 16.7 9.52 

Valid N 37 31 26 N/A 35 34 

OC- Phase 2

Average 8.43 8.49 8.49 7.84 7.60 10.5 

Median 8.28 6.63 8.24 7.77 7.22 9.62 

SD 2.97 4.90 3.16 3.30 2.44 4.15 

Min 2.88 5.32 3.66 2.58 2.30 4.31 

Max 15.7 22.7 17.2 14.9 13.2 22.3 

Valid N 43 13 40 29 39 30 

EC- Phase 1

Average 0.89 0.70 1.17 N/A 0.64 1.54 

Median 0.66 0.60 0.98 N/A 0.54 1.31 

SD 0.52 0.43 0.59 N/A 0.44 0.87 

Min 0.07 0.09 0.54 N/A 0.02 0.25 

Max 1.99 1.94 2.90 N/A 1.65 3.70 

Valid N 69 60 50 N/A 66 66 

EC- Phase 2

Average 2.78 2.52 2.70 2.69 2.43 3.79 

Median 2.67 2.28 2.66 2.74 2.27 3.50 

SD 1.53 0.57 1.20 1.53 1.34 1.35 

Min 0.48 1.74 0.63 0.53 0.21 0.57 

Max 5.92 3.74 5.02 5.32 5.79 6.64 

Valid N 43 13 40 29 39 30 
ULTRAFINE PARTICLES 

Van Nuys Airport

Ultrafine particle (UFP) number concentration measurements (#/cm3

) were taken 

between November 2005 and March 2006 (Phase 1) and again from July to September of 

2006 (Phase 2) at four selected sites of the Van Nuys Airport: the Golf Course, VOR, 

Holmes School (only during Phase 1), and National Guard (only during Phase 2) stations. 

Butanol-based condensation particle counters (CPC) were used at all sites throughout the 

two monitoring campaigns. The highly resolved (1-min) data were averaged over 1-hr 

periods to facilitate comparison among these sites, and average diurnal variation plots 

were obtained to gain some insight into how UFP levels changed throughout the day. 

Overall, the data collected at the Van Nuys stations were found to be dynamic in range, 

with significant variability over very short temporal and spatial scales. A more in-depth 

analysis of these data is described below for each of the two monitoring periods. 

Phase 1(November 2005 - March 2006) 

Figure 19 (main panel) illustrates the representative time evolution of the 1-hr 

UFP count measured at all monitored locations between 02/10/06 and 02/28/06, and 

shows that during the winter months the highest particle number concentrations were 

observed at the VOR site, close (about 150 m) to the north side of the airport and under 

the fixed wing arrival/departure route. On 2/13/06 at 17:00 the 1-hr UFP count level at 

this station peaked at a maximum value of about 203,000 #/cm3

, a concentration 19 and 

six times higher than that measured at the Golf Course and at the Holmes School sites, 

respectively, during the same time frame and further away from the airport fence-line. 

The latter station was set-up about 2,400 m north-west of the airport and, although 

airplanes were observed directly over the school on several occasions, it can be 

considered to be typical of background conditions in the study area. 

44 
Figure 19 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3

) at the Van Nuys Airport measured from 02/10/06 to 02/28/06. Hourly data were 

averaged from 1-min values to facilitate comparison among sites (top panel). An example 

of more resolved 1-min data is shown in the magnified portion of the graph within broken 

lines 

45 
46 

When averaged across the entire duration of Phase 1, the particle count at the 

VOR site (~32,100 #/cm3

) was 1.4 times higher than that at the Golf Course station 

(~23,400 #/cm3), and 3.6 times more elevated than that at the Holmes School site (8,900 

#/cm3) (Table 8). These results are in line with those obtained at the Santa Monica 

Airport during this and previous studies (e.g. Hu et al., 2009), where measured UFP 

concentrations decreased with increasing distance from the runway. 

Table 8 Average and median ultrafine particle (UFP) number concentrations (μg/m3

) at 

the Van Nuys Airport stations during Phase 1 (November 2005 - March 2006). Minimum 

(Min) and maximum (Max) values, standard deviations (SD), and the total number of 

valid samples (Valid N) have also been included 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard 

UFP number (#/cm3

) - Phase 1 

Average 23365 8892 32084 N/A 

Median 18914 7124 26265 N/A

SD 19600 6423 23307 N/A

Min 1691 1389 1949 N/A

Max 182581 136558 202621 N/A

Valid N 2065 1634 2157 N/A

A closer look at the more resolved 1-min data revealed the presence of sharp 

particle count peaks at both the VOR and, less frequently, the Golf Course sites (see 

magnified portion of Figure 19), probably caused by aircraft takeoffs/landings. A few 

occasional spikes in UFP count were also observed at the Holmes School station (not 

shown), and were likely attributable to landing aircraft passing overhead, or nearby 

vehicular traffic. Between peak events the counts generally returned to levels closer to 

those in background air. Because of limitations with the data-logging system connected 

to the butanol-based CPCs, particle counts higher than 260,000 #/cm3 could not be 

measured at VNA sites during Phase 1. It is likely that the actual maximum UFP peaks 

corresponding to periods of aircraft operations were higher than the instrument threshold, 

but less than 0.45, 0.15 and 0.05% of all 1-min measurements at the VOR, Golf Course, 

and Holmes School sites, respectively, were equal to and likely higher than 260,000 

#/cm3

. The effect of underestimating these extreme data-points on comparisons of 1-hr 

average particle levels across sites is minimal. This limitation of the data-logging systems 

was corrected before the beginning of Phase 2. 

Unfortunately, detailed information about the aircraft operating at VNA (e.g. 

model and engine type) and their takeoff/landing schedule was not available at the time 

of the study, and the effect of aircraft movements on the magnitude of the measured UFP 

peaks could not be assessed at VNA sites. However, while working at the VOR station 

AQMD staff members reported that observations of particle count peaks corresponded 

with visual sightings of aircrafts preparing from departure, taking off, or landing, with a 

short delay between the sighting and the peak count recorded on the instrument. It is 
interesting to note that a few recent field campaigns conducted both in the United States 

and in Europe (i.e. APEX, EXCAVATE and AIRPUR) have indicated that while the PM 

mass in the exhaust of turbine engines is essentially a conserved quantity as the plume 

dilutes downwind, the particle number is probably a consequence of post emission 

condensation (Wey et al., 2006; Lelievre et al., 2006; Herndon et al., 2008). In particular, 

formation of UFPs by nucleation seems to occur up to a distance of 25 m from the exit of 

the engine (Lelievre et al., 2006). 

Figure 20 shows the average diurnal profile of hourly particle number 

concentrations at VNA monitoring sites. Whether the “bimodal” appearance of the 

particle count distribution (with peaks between 7:00 and 10:00 am, and from 3:00 to 

8:00pm) can be attributed to airport activities or to rush hour traffic from the highly 

trafficked surface streets surrounding the airport (e.g. Roscoe Blvd. and Balboa Blvd.) 

cannot be assessed from the available data. Ultrafine particle levels at night and early in 

the morning (i.e. from 22:00 to 03:00) suggest a substantial decrease in particle count as 

the airport activities and the vehicular traffic subsided in the evening hours. 

Figure 20 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3

) measured at three sites of the Van Nuys Airport (i.e. Golf Course, VOR, and 

Holmes School stations) during Phase 1 (November 2005 - March 2006) 

0

10000

20000

30000

40000

50000

60000

70000

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

# ptcl/cm3

Van Nuys Airport - Phase 1

Golf Course

VOR Site

Holmes School

Phase 2 (July - September, 2006) 

47 

The UFP levels measured at VNA in the summer/fall period were significantly 

lower than those observed during Phase 1, but followed a similar concentration gradient 

across all available sampling locations (see the main panel of Figure 21 for a 

representative time series from 09/01/06 to 09/18/06). Particle count data at the Holmes 

School (background) station were not available during this part of the study since the site 

was no longer available. Ultrafine particle measurements were carried out at the National 

Guard station instead, within the north-west perimeter of the airport complex and away 

from the fixed wing arrival/departure routes or traffic paths. Also in this case, the highest 

1-hr particle count peaks (between 70,000 and 115,000 #/cm3

) were measured at the 

VOR site, and were about half of the highest number concentrations observed at the same 

location during Phase 1. On 9/15/06 at 15:00 the particle number concentration at the 
VOR station increased to a maximum value of about 115,000 #/cm3

, about ten and 13 

times the corresponding count levels measured at National Guard and at the Golf Course 

sites, respectively. 

Figure 21 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3

) at the Van Nuys Airport measured between 09/01/06 and 09/18/06. Hourly data 

were averaged from 1-min measurements to facilitate comparison among sites (top 

panel). An example of more resolved 1-min data showing elevated UFP levels from 

09/07/06 to 09/09/06 is illustrated in the magnified portion of the graph within broken 

lines

When averaged across the entire duration of Phase 2, the UFP concentration at the 

VOR site (~19,200 #/cm3

) was only slightly more elevated than that measured at the 

National Guard (16,400 #/cm3

) and at the Golf Course (11,700 #/cm3) stations (Table 9) 

Lower concentrations during the summertime period are expected for most air pollutants, 

mostly because of a decreased atmospheric stability and less frequent inversions, which 

favor atmospheric dispersion. 

48 
49 

Table 9 Average and median ultrafine particle (UFP) number concentrations (μg/m3) at 

the Van Nuys Airport stations during Phase 2 (July - September, 2006). Minimum (Min) 

and maximum (Max) values, standard deviations (SD), and the total number of valid 

samples (Valid N) have also been included 

 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard 

UFP number (#/cm3

) - Phase 2 

Average 11740 9115 19154 16404 

Median 11116 8340 17181 15197 

SD 4093 3868 10878 7719 

Min 3171 1327 3652 3519 

Max 42494 34182 114296 62955 

Valid N 1055 290 1005 726 

A more in depth analysis of the highly resolved 1-min data confirmed that, 

although sharp peaks as high as 300,000-400,000 #/cm3 (probably associated with aircraft 

takeoffs or landings) were observed on different occasions at the VOR site, the overall 

UFP levels measured during the second part of the sampling campaign were significantly 

lower than those seen during Phase 1 (magnified portion of Figure 21). However, on 

09/08/06 at 16:09 the 1-min ultrafine particle concentration at the VOR station reached a 

maximum of 427,000 #/cm3, a value 32 and 36 times more elevated than those at the Golf 

Course and National Guard sites during the same time period. No information about the 

operations schedule at VNA or local roadway traffic is available to specifically identify 

the cause of that high particulate count value. 

Figure 22 shows the average diurnal profile of hourly particle number 

concentrations observed at VNA sites during Phase 2. As during the fall/winter period, 

the highest particle number counts throughout the warmer months occurred from late 

morning to late afternoon. Ultrafine particle concentrations at night and early in the 

morning (i.e. from 22:00 to 03:00) were typically comparable at all stations, suggesting a 

substantial decrease in UFPs in and around the VNA area as the airport activities and the 

vehicular traffic subsided in the evening hours. 
Figure 22 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3

) measured at three sites of the Van Nuys Airport (i.e. Golf Course, VOR, and 

National Guard stations) during Phase 2 (July - September, 2006) 

0

10000

20000

30000

40000

50000

60000

70000

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

Van Nuys Airport - Phase 2

Golf Course

VOR Site

National Guard

# ptcl/cm3

Santa Monica Airport

Ultrafine particle number concentrations (#/cm3

) were measured between April 

and July 2006 (Phase 1) and from October 2006 to February 2007 (Phase 2) at five 

selected sites of the Santa Monica Airport, namely East Tarmac, Ernst Residence, West 

Tarmac, Richland School, and Marine Park (only during Phase 2). The highly resolved 

(1-min) data were averaged over 1-hr periods to facilitate comparison among these sites. 

Average diurnal variation plots were also obtained for all stations to gain some insight 

into how UFP levels changed throughout the day. As at VNA, the data collected at SMO 

were found to be very dynamic in range, with even higher spatial and temporal 

variabilities. Because the terms of the loan for the butanol-based CPCs used during the 

first phase of the Santa Monica field campaign expired at the end of September 2006, 

water-based CPCs were purchased by AQMD and used during Phase 2. 

Phase 1(April - July, 2006) 

The time series plot in Figure 23 (main panel) summarizes observations made 

from 05/03/06 to 05/24/06 and illustrates how during the first phase of the study the UFP 

number concentration gradient was affected primarily by proximity to the take-off 

location on the airport’s runway. The highest 1-hr average particle count peaks were 

measured at the East Tarmac site, approximately 35 m west from the end of the runway 

and near the blast-fence. In particular, on 05/11/06 at 14:00 the 1-hr ultrafine particle 

count level at this station increased to about 510,000 #/cm3

, a concentration five times 

higher than that recorded at the Ernst Residence site (about 100 m downwind of the 

runway but outside the airport’s fence-line) during the same time period. The 

corresponding ultrafine levels measured at the West Tarmac (around 100 m west from the 

southern end of the runway), Richland School (the furthest site from SMO), and Marine 

Park (background) stations were 7,500, 7,000, and 6,500 #/cm3

, respectively, or 70 to 80 

times lower than those at East Tarmac. These findings are consistent with an aircraft 

50 
source given the stations relative proximity to the area where aircraft were idling and 

taking off, and the predominant wind flow (from the south-southeast direction). 

Figure 23 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3) at the Santa Monica Municipal Airport measured from 05/03/06 to 05/24/06. 

Hourly data were averaged from 1-min measurements to facilitate comparison among 

sites (top panel). An example of more resolved 1-min data showing elevated UFP levels 

from 05/11/06 to 05/12/06 is illustrated in the magnified portion of the graph within 

broken lines

When averaged across the entire duration of Phase 1, the UFP level at the East 

Tarmac site (~52,200 #/cm3) was two times higher than that at the Ernst Residence 

station (~26,300 #/cm3), and seven times more elevated than that at the background site 

(Marine Park; 8,000 #/cm3

) (Table 10). Our results are lower than those obtained by Hu 

et al. (2009) during a four day campaign conducted in the spring/summer of 2008, when 

the study-average UFP concentrations at two sites 80 and 100 m downwind of the airport 

were 106,000 and 97,000 #/cm3

, respectively, or about 10 times the corresponding 

background levels for all measurement days combined. One explanation for this 

51 
52 

discrepancy is that while our CPCs were operated 24-hours, Hu et al. measured only 

daytime UFP number concentrations and within a much shorter time frame (i.e. 4 to 6 

hours for four sampling days) when the airport was in operation. 

Table 10 Average and median ultrafine particle (UFP) number concentrations (#/cm3) at 

the Santa Monica Airport stations during Phase 1 (April - July, 2006). Minimum (Min) 

and maximum (Max) values, standard deviations (SD), and the total number of valid 

samples (Valid N) have also been included 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

UFP number (#/cm3

) - Phase 1

Average 13273 8037 26284 52240 8406 

Median 10011 7216 14963 31097 7316 

SD 9135 4505 28147 67741 5310 

Min ND 1684 1221 1345 1444 

Max 80548 53010 312524 513135 96942 

Valid N 2804 1753 1846 930 2469 

An analysis of the more resolved 1-min data revealed the presence of spikes in 

particle number concentrations as high as 9,000,000 #/cm3, as measured on 05/11/06 at 

18:45 at the East Tarmac (magnified portion of Figure 23). These exceptionally elevated 

levels were rare, but 1-min maxima between 4,000,000 and 4,500,000 #/cm3 were 

relatively more common at the East Tarmac and, occasionally, at the Ernst Residence 

site. The 1-min concentration measured at the Marine Park (background) site was as 

much as 2,100 times lower than the corresponding value at the East Tarmac. However, a 

relative decrease in 1-min background particle counts between 100 and 600 times was 

more common during Phase 1. For comparison, Hu et al. (2009) observed that the 

maximum 1-min UFP measured in Clarkson Rd. (100 m north from the runway of SMO) 

was 2,200,000 #/cm3

, or about 440 times the corresponding summer background level 

(~5,000 #/cm3), which is consistent with our observations at the Ernst Residence site (setup in close proximity to Clarkson Rd.) during the same season. Increased peak 

concentrations in UFP counts were also measured near the Los Angeles International 

Airport (LAX) during a study carried out between September 2005 and March 2006 by 

Fanning et al. (2007). Here, the highest peaks in UFP number levels were clearly 

correlated with aircraft take-off events, and 2% of the measured data points (recorded at 

1-sec intervals) exceeded 10,000,000 #/cm3

, the upper limit of the CPCs used for that 

study. In earlier work conducted by Westerdahl et al. (2008) at the same international 

airport (LAX), data collected about 100 m downwind of one of the south runways 

revealed that particle counts (measured at 10-sec intervals) reached approximately 

4,800,000 #/cm3

 during some of the observed take-offs. 
The effect of aircraft movements on the magnitude of the UFP number peaks 

measured at SMO sites is illustrated in Figure 24, which shows the particle number 

concentration time series at the East Tarmac, West Tarmac, Ernst Residence and 

Richland School stations on 07/07/06. As expected, measurements at the East Tarmac 

and Ernst Residence sites peaked when aircraft where either taxing or taking-off. 

Figure 24 Ultrafine particle (UFP) number concentrations data showing the impact of 

aircraft movements at the East Tarmac, Ernst Residence, West Tarmac, Richland 

Elementary School sites on 07/07/06 

These time periods (corresponding to the broken lines in Figure 24) have been 

highlighted in red in Table 11, which also includes detailed information about the model 

and identification number of the aircraft associated with these increases in particle 

number concentration. AQMD staff members operating at the East Tarmac site reported 

that observations of particle count peaks during takeoffs corresponded with visual 

sightings of aircraft preparing from departure, with a short delay between the sighting and 

the peak count recorded on the instrument (often accompanied by an odor of jet-fuel). 

53 
54 

Jets and piston driven planes taxi a few hundred meters from the take-off area to 

the north of the runway near the East Tarmac site. As summarized in Table 11, the taxi 

time for most aircraft is between two and five minutes (for comparison, the acceleration 

time on the runway during takeoff is only of 20-30 seconds). Also, because the jet flight 

path from SMO intersects LAX flight paths less than 20 Km after takeoff, aircraft 

departing from SMO must wait for permission from LAX, resulting in an additional 

waiting time of up to 5 minutes or more. Therefore, the typical total taxi-waiting time 

observed for an average airplane (“Grand Total” in Table 11) during our field campaign 

was between 4 and 10 minutes. It is likely that these relatively long standby periods 

contribute to increased the concentrations of UFPs and other combustion products (e.g. 

BC) in the vicinity of the takeoff area. 

Table 11 Santa Monica Airport take-off observation data on 7/17/2006. Time periods 

associated with the particle number concentration peaks in Figure 24 are highlighted in 

red 

Observation 

No. 

Aircraft 

No. Aircraft Type 

Taxi 

Begins 

(a) 

Hold 

Begins 

(b) 

Departure

Time 

(c) 

Total 

Taxi 

(b-a) 

Total

Hold 

(c-b) 

Grand 

Total 

(c-a) 

1 480DG Cessna 560 7:34:19 7:37:22 7:39:01 03:03 01:39 04:42 

2 374QS Cessna 560 7:39:57 7:43:25 7:46:41 03:28 03:16 06:44 

3 25FS Cessna 550 8:13:27 8:16:16 8:17:27 02:49 01:11 04:00 

4 555LG CL-600-2B16 8:47:50 8:53:06 8:57:25 05:16 04:19 09:35 

5 834QS Cessna 560 9:12:26 9:16:14 9:22:16 03:48 06:02 09:50 

6 238SM Cessna 560XL 9:31:11 9:35:09 9:37:40 03:58 02:31 06:29 

7 268QS Falcon 2000 9:38:00 9:41:23 9:45:51 03:23 04:28 07:51 

8 647QS Cessna 560XL 9:58:00 10:01:16 10:03:12 03:16 01:56 05:12 

9 827RM Beech B100 10:04:04 10:06:17 10:12:40 02:13 06:23 08:36 

10 25LZ Cessna 525A 10:22:20 10:26:50 10:29:26 04:30 02:36 07:06 

11 884QS Hawker 800XP 10:48:00 10:50:28 10:53:40 02:28 03:12 05:40 

12 426CH Cessna 560XL 10:55:24 10:57:41 10:59:40 02:17 01:59 04:16 

13 324MM Beech 400 10:58:41 11:01:14 11:09:15 02:33 08:01 10:34 

14 169TA CL-600-2A12 12:35:11 12:38:20 12:39:12 03:09 00:52 04:01 

15 281QS Falcon 2000 13:31:41 13:33:45 13:37:51 02:04 04:06 06:10 

16 268QS Falcon 2000 14:18:03 14:20:45 14:24:22 02:42 03:37 06:19 

17 227WS Cessna 560 14:18:03 14:21:42 14:25:30 03:39 03:48 07:27 

18 105AX Beech 400A 15:20:21 15:23:38 15:27:07 03:17 03:29 06:46 

19 51HF Cessna 525A 15:48:11 15:50:20 15:53:37 02:09 03:17 05:26 

20 777DY Cessna 525A 15:50:08 15:53:47 15:54:48 03:39 01:01 04:40 

21 411QS G-IV 15:51:52 15:54:29 15:56:20 02:37 01:51 04:28 

22 931QS Cessna 750 16:38:21 16:41:19 16:43:45 02:58 02:26 05:24 
As suggested by the average diurnal profile of hourly particle number 

concentrations measured at SMO sites (Figure 25), the highest traffic activity during 

Phase 1 occurred between 09:00 and 17:00. Ultrafine particle levels at night and early in 

the morning (i.e. from 22:00 to 03:00) were typically comparable at all stations, 

suggesting a substantial decrease in particle count as the numbers of take-offs and 

landings subsided in the evening hours and ceased overnight. Hu et al. (2009) analyzed 

airport count information from traffic logs provided by SMO, and reported that in the 

spring/summer of 2008 the great majority of aircraft operations (diurnal hourly arrivals 

and departures) took place from 09:00 and 20:00, consistent with our results. The Santa 

Monica Airport allows operations of nonemergency aircraft only from 07:00-23:00 on 

weekdays and 08:00-23:00 on weekends due to noise ordinances. 

 

Figure 25 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3) measured at five sites of the Santa Monica Airport (i.e. East Tarmac, West 

Tarmac, Ernst Residence, Richland School, and Marine Park) during Phase 1 (April - 

July, 2006) 

0

20000

40000

60000

80000

100000

120000

140000

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

# ptcl/cm3

Santa Monica Airport - Phase 1

West Tarmac

East Tarmac

Ernst Residence

Richland School

Marine Park

Phase 2 (October 2006 - February 2007) 

During the second field campaign at SMO, the UFP concentrations (measured 

using water-based CPCs) were substantially lower than those observed during Phase 1, 

and more homogeneous across sampling sites (main portion of Figure 26). The 

magnitude of the highest 1-hr peaks at the East Tarmac and Ernst Residence stations 

(124,000 and 155,000 #/cm3

, respectively) were comparable to the maximum 1-hr 

ultrafine levels measured at the West Tarmac site (122,000 #/cm3

) and 2-2.5 times higher 

than that the Richland School station (64,000 #/cm3; 900 m north-east of SMO). Because 

of an instrument malfunction no particle count data were obtained at the Marine Park 

(background) station, which makes it difficult to estimate the relative increase in UFP 

concentration downwind of the runway with respect to background conditions. 

55 
Figure 26 Representative hourly average ultrafine particle (UFP) number concentrations 

(#/cm3

) at the Santa Monica Municipal Airport measured from 01/01/07 to 01/23/07. 

Hourly data were averaged from 1-min measurements to facilitate comparison among 

sites (top panel). An example of highly resolved 1-min data showing elevated UFP levels 

from 01/02/07 to 01/03/07 is illustrated in the magnified portion of the graph within 

broken lines 

56 
57 

When averaged across the entire duration of Phase 2, the UFP level at the East 

Tarmac and Ernst Residence sites (~27,900 and 25,000 #/cm3

, respectively) were still 

about 2.5 times higher than those at the other two sites (Table 12). 

Table 12 Average and median ultrafine particle (UFP) number concentrations (#/cm3

) at 

the Santa Monica Airport stations during Phase 2 (October 2006 - March 2007). 

Minimum (Min) and maximum (Max) values, standard deviations (SD), and the total 

number of valid samples (Valid N) have also been included 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

UFP number (#/cm3

) - Phase 2

Average 11503 N/A 24987 27907 11404 

Median 9454 N/A 18468 22002 9053 

SD 9398 N/A 20650 21023 9724 

Min 167 N/A 1135 1200 1167 

Max 63722 N/A 155498 124213 121802 

Valid N 1048 N/A 1956 1312 1908 

The fact that most of the 1-min peak concentrations measured at the East Tarmac 

and Ernst Residence sites (see the magnified portion of Figure 26 for data collected 

between 01/02/07 and 01/03/07) were never above 500,000 #/cm3 (more than one order 

of magnitude less than the highest levels recorded during the spring/summer campaign) is 

likely related to limitations of the water-based CPCs (i.e. their detectable particle range is 

between 0 and ~500,000 #/cm3

). Also, it is possible that the counting efficiency of waterbased CPCs for particles smaller than 20 nm in diameter (which comprise a substantial 

fraction of the total number of particles in aircraft emissions) is significantly lower than 

that of their butanol-based counterparts (Herman et al., 2007; Mordas et al., 2008). 

Although these measurement uncertainties limit our ability to provide a more quantitative 

assessment of the effect of aircraft takeoffs/landings at sites upwind and downwind of the 

SMO runway during Phase 2, 1-min particle counts at the East Tarmac and Ernst 

Residence sites were still up to 70 times higher than those observed at the other two 

stations further away from the airport (i.e. Richland School and West Tarmac). 

Recent studies conducted at the Santa Monica Airport (Hu et al., 2009) and at 

LAX (Fanning et al., 2007; Westerdahl et al., 2008) have shown that UFPs downwind of 

these two airports were dominated by freshly generated particles with peak modes 

between 10 and 15 nm, while the upwind aerosol was comprised by larger aged particles 

with a diameter of about 90 nm. There is now a growing body of work concerning the 

potential for adverse health effects from exposure to UFPs emitted from different 

combustion processes (Xia et al., 2004; Delfino et al., 2005; Sioutas et al. 2005; Nel et 

al., 2006; Pope and Dockery, 2006), and the presence of highly elevated ultrafine particle 
levels downwind of general aviation and international airports may have potential health 

implications for persons living in adjacent areas. 

Figure 27 shows the average diurnal profile of hourly particle number 

concentrations observed at SMO sites during Phase 2. As during the first phase of the 

study, the highest traffic activity occurred between 09:00 and 18:00. Average UFP levels 

at night and early in the morning (i.e. from 22:00 to 03:00) were comparable at all 

stations, suggesting a substantial decrease in particle count as airport activities subsided 

at night. 

Figure 27 Average diurnal profiles of the ultrafine particle (UFP) number concentration 

(#/cm3

) measured at four sites of the Santa Monica Airport (i.e. East Tarmac, West 

Tarmac, Ernst Residence, and Richland School) during Phase 2 (October 2006 - February 

2007) 

0

20000

40000

60000

80000

100000

120000

140000

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

# ptcl/cm3

Santa Monica Airport - Phase 2

West Tarmac

East Tarmac

Ernst Residence

Richland School

DAILY CARBON MONOXIDE (CO) VARIATIONS 

Carbon monoxide (CO) was measured at all “fully” instrumented sites by mean of 

Dasibi® 3008 CO Analyzers. Attempts were made to use personal monitors at the 

“partially” instrumented stations, but the resulting data are not reliable and will not be 

discussed in the following paragraphs. Because of the malfunctioning of several monitors 

deployed at VNA and some data recovery problems, CO concentrations for Phase 1 are 

only available at the VOR site. None of the 1-hr average CO concentrations measured at 

both VNA and SMO was above the current U.S. EPA NAAQS for CO (35 ppm, not to be 

exceeded more than once per year). 

The average diurnal profile of CO at VNA during Phases 1 and 2 (Figures 28a 

and 28b, respectively) followed a distinctively different pattern from that observed for 

other combustion-related pollutants such as UFP count and BC, with peak values during 

morning rush hour traffic (average peak concentrations were between 1 and 1.4 ppm) and 

lower levels (typically below 0.2 ppm) in the afternoon. This indicates that the 

concentration of this gaseous pollutant was probably dominated by contributions from 

motor-vehicle emissions from nearby roadways and freeways, and surface streets, and 

that the influence from airport-related activities was not significant. This seems to be 

58 
particularly true at the VOR and Golf Course sites (outside the airport fence-line and 

where the highest CO levels were generally measured) and at the National Guard station. 

Similar results were obtained from previous work conducted in close proximity to 

international airports. For example, using nonparametric regression of hourly pollutant 

concentrations on wind speed and direction, Yu et al. (2004) studied the impact of two 

major urban airports, LAX and the Hong Kong International Airport (HKG), on local air 

quality. At both locations CO was dominated by emissions from ground vehicles going in 

and out of the airport. However, near HKG Airport operations were occasionally found to 

be a significant contributor to CO and respirable suspended particles. Emissions from the 

parking lots surrounding an airport area have also been associated with increased CO 

concentrations (Schurmann et al. 2006). 

Figure 28 Average diurnal variations of carbon monoxide (CO; ppm) at four sites of the 

Van Nuys Airport (i.e. Golf Course, VOR, Holmes School and National Guard). 

Measurements were taken from a) November 2005 to March 2006 (Phase 1) and b) 

between July and September 2006 (Phase 2). Because of a malfunctioning of several 

monitors deployed at VNA and issues related to data recovery, CO concentrations for 

Phase 1 are only available at the VOR site 

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

CO (ppm)

Van Nuys Airport - Phase 1

VOR SIte

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

Van Nuys Airport - Phase 2

Golf Course

VOR Site

Holmes School

National Guard

CO (ppm)

a) 

b) 

59 
60 

As observed at VNA, the average diurnal profile of CO at SMO followed a 

distinctively different pattern from that observed for UFP count and BC (Figures 29). 

Also in this case, increased CO values during morning rush hour (not higher, on average, 

than 1.4 ppm) and minimum values in the afternoon (generally below 0.2 ppm) suggest 

that the concentration of this gaseous pollutant was mostly influenced by motor-vehicle 

emissions from roadways or freeways in the SMO area. The slightly higher CO levels 

measured at the Ernst Residence site during Phase 1 (Figure 29a) are probably due to the 

close proximity of this station to Bundy Dr. and National Blvd, two highly trafficked 

streets adjacent to the north-east side of the airport. The same relative increase in CO at 

the Ernst Residence station was not observed during the second part of the study (Figure 

29b), when the average CO levels at all monitored sites were almost three times higher 

than during Phase 1. 

It is important to note that short term increases in CO concentrations from aircraft 

emissions have been typically observed when measurements are taken within a short 

distance from the plume of an engine. During a sampling campaign conducted at the 

Zurich Airport (Switzerland) Schurmann et al. (2007) collected real-time CO data in an 

area where four aircraft were generally parked and simultaneously handled. Here each 

aircraft movement on the taxiway led to short-term (3-min) CO peaks as high as 3,900 

ppm at a distance between 50 and 100 m behind the aircraft, a concentration about 40 

times higher than the corresponding background level. At low power setting such as 

when idling or taxiing, jet and piston engines emit high amounts of CO (and incompletely 

oxidized hydrocarbons), due to incomplete combustion. 

A summary of all CO concentration data collected at VNA and SMO during this 

study can be found in Appendix A. 
Figure 29 Average diurnal variations of carbon monoxide (CO; ppm) at different four 

sites of the Santa Monica Municipal Airport, namely West Tarmac, Ernst Residence, 

Richland School, and Marine Park. Measurements were taken a) from April to July 2006 

(Phase 1) and b) between October 2006 and March 2007 (Phase 2) 

0

0.2

0.4

0.6

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

CO (ppm)

Santa Monica Airport - Phase 1

West Tarmac

Ernst Residence

Richland School

Marine Park

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0:001:002:003:004:005:006:007:008:009:00

10:00

11:00

12:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:00

CO (ppm)

Santa Monica Airport - Phase 2

West Tarmac

Ernst Residence

Richland School

a) 

b) 

TRACE ELEMENTS 

As discussed in the previous sections, particle and gaseous pollutants in and 

around an airport area can be emitted from a multitude of airport-related sources such as 

re-fueling, ground support vehicles, passenger cars coming in and out the airport, but also 

from nearby traffic. Therefore, estimating the relative contributions of these and other 

point and area sources to the measured atmospheric concentrations of the targeted air 

pollutants can be challenging. The elemental composition of the collected aerosols can be 

used to provide an important fingerprint to help distinguish among emission sources from 

different environments including, roadways (Ntziachristos et al., 2007b), harbor/ports 

(Arhami et al., 2009), and airports (Groma et al., 2008). Although more than 40 trace 

elements were analyzed on the PM2.5 samples collected at the Van Nuys and Santa 

Monica Airports, only the concentrations of those species that were present in significant 

amounts (i.e. Mg, Al, Si, S, K, Ca, Fe, and Ba) will be discussed in the following 

61 
62 

paragraphs. The temporal and spatial distribution of lead has already been characterized 

in a previous section. 

The spatial distribution of each trace element measured at VNA was quite 

uniform across all sampling stations (i.e. Golf Course, VOR, Holmes School, and 

National Guard, all set-up outside the airport fence-line), regardless of their relative 

distance from the airport and runway (Figure 30). Typically, S was the most abundant 

element in the collected PM samples, followed by Mg, Ca, K, Fe, Si, Ba and Al. Sulfur is 

typically generated from combustion sources such as gasoline and diesel-powered motorvehicles and aircraft, and it is a component of both Avgas and jet fuel. Previous studies 

conducted in the Los Angeles area (Ntziacristos et al., 2007b; Arhami et al., 2009) have 

indicated that S is present in all three fractions of the atmospheric PM (ultra-fine, 

accumulation and coarse), with high values found in both ultra-fine and accumulation 

mode particles. During a recent campaign conducted between February and April 2006 

and in close proximity to and downwind of the I-710 freeway (the primary route for 

heavy-duty diesel truck traffic between the ports complex of Long Beach/San Pedro and 

the shipping yards in East Los Angeles) Ntziachristos et al. (2007b) reported that the 

study average S concentration in PM2.5 particles was about 300 ng/m3

. This level is 

comparable to that observed at the Van Nuys sites during Phase 1 (240 to 280 ng/m3

) 

(Figure 30a), but is more than five times lower than the range of values measured during 

Phase 2 (1,520 to 1,580 ng/m3

) (Figure 30b). This substantial difference can probably be 

attributed to increased presence of secondary sulfate particles during the summer 

campaign (Phase 2). The remaining trace elements detected in VNA samples mainly 

originate from mechanical processes such as vehicle brake abrasion (Ba and Fe; Sanders 

et al., 2003) or from re-suspension of crustal materials (i.e. Mg, Ca, K, Fe, Si, and Al), 

and their concentrations are well within those reported in previous road-side, tunnel, and 

port studies conducted in the Los Angeles Basin (Singh et al., 2002; Ntziachristos et al., 

2007b; Arhami et al., 2009) and other urban areas (Birmili et al., 2006). Calcium (used as 

anti-wear, detergent, and stabilizing additive in oils) has also been proposed as marker for 

lube-oil combustion. 
Figure 30 Ambient concentrations of selected metals in fine particulate matter (PM2.5) at 

different sampling locations of the Van Nuys Airport during a) Phases 1 (from November 

2005 to March 2006) and b) Phase 2 (from July to September 2006) 

Similarly, the concentrations of most trace elements measured at SMO were 

comparable at all stations (i.e. Richland School, Marine Park, East Tarmac, West Tarmac, 

and Ernst Residence), regardless of their relative distance from the airport area (Figure 

31). Average S concentrations were substantially lower throughout the second part of the 

study (October 2006–February 2007), with values ranging from 175 ng/m3 at the East 

Tarmac site (in very close proximity to an area where aircraft were idling and taking-off) 

to 200 ng/m3

 at the Richland School site (background station) (Figure 31b). Overall, the 

temporal profile of the trace elements measured at SMO throughout the entire duration of 

this study is variable, with higher Al and S levels in the warmer months and increased P, 

K, Ca and Fe concentrations during the colder period. This is also consistent with 

increased amounts of of secondary sulfate in late spring and early summer. 

Overall, the majority of the trace elements detected in the PM2.5 samples collected 

in Santa Monica probably originated from re-suspension of crustal materials, and their 

concentrations are comparable to those reported in previous studies conducted in the Los 

Angeles Basin (Singh et al., 2002; Ntziachristos et al., 2007b; Arhami et al., 2009) and 

other urban areas (Birmili et al., 2006). A summary of all trace element data collected at 

VNA and SMO during this study can be found in Appendix A. 

63 
Figure 31 Ambient concentrations of selected metals in fine particulate matter (PM2.5) at 

different sampling locations of the Santa Monica Airport during a) Phase 1 (from April to 

July 2006) and b) Phase 2 (from October 2006 to March 2007) 

JET SIGNATURES 

To better characterize the influence of aircraft emissions on the air pollution 

levels at SMO, two canister samples were collected on 05/12/06 at the East Tarmac site, 

one when jet-propelled planes were idling near the runway (sample #1) and one when no 

airplane activity was ongoing (sample #2). On the same day, a third canister sample was 

taken behind the blast-fence when jets were taking-off (sample #3). These air samples 

were then analyzed to determine the concentrations of several relevant VOCs and 

gaseous air toxics. The results of this analysis are reported below in Table 13 and suggest 

that emissions from aircraft idling near the Tarmac (sample #1) increased the 

concentration of many measured pollutants substantially. Of the overall speciated 

mixture, some compounds such as 1,3-butadiene, benzene and toluene are considered to 

be hazardous air pollutants (HAPs), while others (e.g. acetone) may be significant 

contributors to the overall level of VOC emissions but data indicating toxicity are 

lacking. 

It is worth noting that at cruise speed, most aircraft engines convert significantly 

more than 99% of the fuel through complete combustion to CO2 and H2O. However, at 

idle conditions (those most commonly found near the East Tarmac station) less fuel is 

consumed and, in order to maintain a stable combustion at lower power settings, a small 

loss in combustion efficiency occurs. This leads to higher emissions of incompletely 

64 
65 

burned hydrocarbons (Aircraft Engine Speciated Organic Gases: Speciation of Unburned 

Organic Gases in Aircraft Exhaust, prepared by EPA in 2009). 

Interestingly, the concentrations of all gaseous species observed at the East 

Tarmac site while no aircraft activity was ongoing (sample #2) were comparable to those 

measured from the analysis of the canister sample collected behind the blast-fence when 

jets were taking-off (sample #3; see Table 13 for details). This agrees well with the 

results from a previous study conducted at the Logan Airport in Boston, where the 

aircraft exhaust from engine idle and taxiway acceleration was found to contain 

substantially greater concentrations of hydrocarbons (including formaldehyde, 

acetaldehyde, benzene, and toluene) than the exhaust during landing and takeoff 

(Herndon et al., 2005). This observation is also qualitatively consistent with the ICAO 

databank values for hydrocarbon emissions at idle relative to takeoff (ICAO, 2006) 

Table 13 Ambient concentrations (ppb) of several important gaseous pollutants present 

in canister samples collected at the East Tarmac site (samples #1 and #2) and behind the 

blast-fence (sample #3) at SMO 

Sample #1 

East Tarmac 

(Airplanes idling)

(ppb)

Sample #2 

East Tarmac 

(No airplane activity)

(ppb)

Sample #3 

Blast-Fence 

(Airplanes take-off) 

(m+p)-Xylenes 1.32 0.20 0.33 

1,2-Dibromoethane ND ND ND 

1,2-Dichloroethane ND ND ND 

1,2-Dichloropropane ND ND ND 

1,3-Butadiene 7.39 ND 0.38 

Acetone 6.13 4.20 4.01 

Benzene 4.83 0.34 0.44 

Carbon Tetrachloride 0.09 0.09 0.09 

Chloroethene ND ND ND 

Chloroform ND 0.03 0.04 

Ethylbenzene 0.45 0.08 0.12 

MEK ND ND 0.45 

Methylene chloride 0.22 0.20 0.25 

MTBE 0.03 ND ND 

o-Dichlorobenzene ND 0.02 0.03 

o-Xylene 0.39 0.26 0.21 

p-Dichlorobenzene ND 0.02 0.05 

Perchloroethylene 0.04 0.03 0.06 

Styrene 0.67 0.08 0.15 

Toluene 2.37 1.08 0.74 

Trichloroethene ND ND ND 

ND = non detected 
66 

The emission profiles of the two canister samples collected at the East Tarmac 

station were then compared to those of jet fuel exhaust (aircraft exhaust-jet fuel), typical 

gasoline vehicle emissions (gasoline - catalyst - stabilized exhaust - ARB summer 2003), 

and diesel exhaust (farm equipment - diesel - light & heavy), all downloaded from the 

California Air Resource Board (CARB) speciation database for organic compounds 

(ORGPROF; http://www.arb.ca.gov/ei/speciate/speciate.htm). This database provides 

estimates of the chemical composition of emissions for a variety of emission source 

categories, and data are reported as the fraction of the total organic gases (TOG) that are 

reactive organic gases (ROGs). Hence, the concentrations of each species detected in the 

two canister samples collected at the East Tarmac (samples #1 and #2) were converted to 

the corresponding percentage contribution to the total measured gaseous levels to 

facilitate a comparison with the ARB data. 

Formaldehyde and ethylene were not quantified in samples #1, #2, and #3 since 

GC/MS analysis of canister samples is not accurate for formaldehyde detection, and 

ethylene is not considered an air toxic. However, data obtained from the chemical 

analysis of emissions from a commercial aircraft gas turbine engine (a CFM56 high 

bypass turbofan) indicate that the sum of these two compounds alone represent about 

55% of the total speciated non-methane hydrocarbon (NMHC) emissions on a 

concentration basis (Spicer, 1994). The same work also reported that around 40% of the 

organic gas mass was accounted for by the compounds, ethene, formaldehyde, propene, 

ethyne and methane. While different data sets provide detailed information on the 

emission indexes of several air pollutants from various jet-engines types, the exact 

amount of individual organic gases emitted from jet propelled aircraft is difficult to 

quantify because it depends on the type of the engine/airframe being tested, the sampling 

conditions (e.g. engine tests vs ambient sampling near airports), which species are 

included in the total mix, and which measurement technique has been employed for their 

analysis. Recent studies conducted both in the United States and in Europe (Herndon et 

al., 2006; Schürmann et al., 2007) have shown that refueling activities can also alter the 

profile of most hydrocarbons considerably. These factors should be kept in mind while 

comparing the results of the various emission profiles presented below. 

As shown in Figure 32a, sample #1 closely resembles the emission profile of 

typical jet exhaust, which suggests that the ambient air at the East Tarmac site was 

influenced by jet aircraft emissions when idling before take-off. Conversely, the emission 

profile of sample #2 is similar to that of diesel emission (Figure 32b), probably because 

when no airplane activity was taking place near the East Tarmac site the ambient air was 

affected by diesel emissions from vehicles operating within or in close proximity of the 

airport’s perimeter. Lastly, the emission profiles of samples #1 and #2 seem to differ 

from that of gasoline exhaust (Figure 32c), indicating that gasoline-powered vehicles did 

not influence the composition of the two canister samples at the time of sampling. A 

more extensive study and data analysis is needed to confirm these results and to better 

evaluate the contributions of jet exhaust and diesel emissions to the composition of 

ambient air at the East Tarmac site and, in general, in the SMO area. 
Figure 32 Comparison between the emission profiles of the two canister samples collected at the East Tarmac site 

fuel, b) diesel exhausts, and c) gasoline vehicle emissions. Data are expressed as the percentage weight contributio

the total measured organic gas concentration. The emission profiles of jet fuel exhaust (aircraft exhaust - jet fuel), tvehicle emissions (gasoline - catalyst - stabilized exhaust - ARB summer 2003), and diesel exhaust (farm equipme

heavy) were downloaded from the California Air Resource Board (CARB) speciation database for organic compouhttp://www.arb.ca.gov/ei/speciate/speciate.htm) 

a) b) 

(Sample #1: idle) (Sample #1: idle) (S

67 
68 

It is worth noting that the benzene/toluene ratio of sample #1 (canister sample 

affected by emissions from airplanes idling at the East Tarmac) was equal to 2, while the 

corresponding ratio for sample #2 (characteristic of “airport background” conditions) was 

about 0.3. After complete ignition, when the engine temperature of an aircraft is constant 

and relatively high (during taxiing, for example), aromatics tend to crack leading to the 

production of increasing amounts of benzene. Thus for idling conditions, a 

benzene/toluene ratio of about 1.6 is expected (Schurmann et al., 2007). Conversely, the 

characteristic benzene/toluene ratio for kerosene fuel evaporation is about 0.27. 

Therefore, sample #2 might be indicative of fuel evaporation (Schurmann et al., 2007). 

In an attempt to better characterize the hazardous air pollutants (HAPs) speciation 

profile for commercial aircraft engines, the Federal Aviation Administration (FAA) and 

the U.S. EPA have recently reviewed the available HAPs emission data from commercial 

aircrafts (Aircraft Engine Speciated Organic Gases: Speciation of Unburned Organic 

Gases in Aircraft Exhaust, prepared by EPA in 2009). Consolidated HAPs information 

from measurements conducted during the past 35 year using various sampling and 

analysis methods were investigated and combined to provide a single, accurate, and more 

reliable profile. The resulting FAA/EPA document includes results from the work of 

Spicer et al. (1994) on military engines, and from the more recent Aircraft Particle 

Emissions eXperiment (APEX) campaign on commercial aircrafts (see Wey, 2004; 

Onasch et al., 2006; Wey et al., 2006; Lobo et al., 2007, for details). In addition to 

dedicated engine tests, sampling from airports during routing operation (most noticeably 

from the works of Herndon et al., 2006 and Schürmann et al., 2007) have also provided 

useful data for HAPs emissions that have been included in the above mentioned 

FAA/EPA work. 

The speciated data included in this FAA/EPA document were also compared to 

the emission profile of sample #1 at the East Tarmac. No correlation was observed 

between the HAPs emission profile from the EPA/FAA document and that from the 

analysis of sample #2 (top panel in Figure 33). Overall, although our data are based on 

limited measurements, they seem to confirm that emissions from jets idling near the East 

Tarmac before take-off may increase the short term concentrations of several HAPs at 

this location. 
Figure 33 Comparison between the hazardous air pollutants (HAPs) speciation profile 

for commercial aircraft engines emission profiles provided by EPA (Aircraft Engine 

Speciated Organic Gases: Speciation of Unburned Organic Gases in Aircraft Exhaust, 

prepared by EPA in 2009) and those of the two canister sample collected at the East 

Tarmac site when jets were either idling or taking-off (sample #1; bottom panel) and 

when no aircraft activity was ongoing (sample #2; top panel) 

69 
70 

CONCLUSIONS AND RECOMMENDATIONS 

Long-term average concentrations of CO, PM2.5, OC, EC, VOCs, carbonyls and 

trace elements in communities near VNA and SMO were generally similar to, and often 

lower than, those measured elsewhere in the South Coast Air Basin. For these pollutants, 

there were generally no distinguishable concentrations gradients within the studied 

communities which would suggest the airport as a major source. Therefore, emissions 

from aircraft and other airport-related sources are not likely to significantly increase the 

long-term risk associated with exposure to these pollutants. The exception to this general 

finding is TSP lead. Study-average concentrations near VNA and SMO were found to be 

significantly higher than the corresponding levels present in background air or elsewhere 

in the Basin, and the concentration gradient pointed to the runway take-off area as a 

source. Lead is likely emitted from piston-driven engines using leaded general aviation 

fuel. However, the highest lead levels found in this study, which occurred on airport 

property, are still below the recently tightened U.S. EPA National Ambient Air Quality 

Standard for lead. 

Near-continuous measurements obtained during this and other field campaigns 

have shown that sharp and rapid increases (e.g. 1-min) in the concentrations of UFPs 

occur when jet aircraft are idling, taking off, and sometimes landing. At VNA the highest 

particle counts were generally measured about 150 m from the north side of the airport, at 

a site located under the fixed wing arrival/departure route. Here, the average UFP number 

concentration measured in the colder months (fall 2005 - winter 2006) were 3.6 times 

higher than those observed at a background site set-up about 2,400 m northwest of the 

airport. At SMO the spring/summer 2005 average UFP levels recorded 35 m west from 

the end of the runway and near the blast-fence were two times higher than those 100 m 

north (and downwind) of the runway and seven times higher than those in background 

air. Overall, our results are in line with those obtained by Hu et al. (2009) during a four 

day campaign conducted at SMO during the spring/summer of 2008, when the studyaverage UFP concentrations at two sites 80 and 100 m downwind of the airport were 

about 10 times the corresponding background levels for all measurement days combined. 

Our analysis of aircraft activity data at SMO confirmed that peaks in UFP concentration 

at the downwind sites were associated with jet aircraft take-off operations. These shortlived spikes in UFP levels were up to 2,000 times higher than background levels, and 

often extended into residential areas. Further work is needed to better understand the 

emission rates, atmospheric behavior, physical and chemical properties, and health 

consequences of both short-term and long-term exposure to UFP emitted from jet aircraft. 

The majority of previous studies focusing on the characterization of engine 

exhaust and the effect of emissions on local air quality have been conducted on large 

commercial jets. Although there are likely differences in the chemical and physical 

characteristics of emissions from piston-driven airplanes, small private jets, and larger 

commercial aircraft, the results of our study are consistent with previous works at LAX 

and other large international airports in the US and in Europe. 

The monitoring plan developed for this study was based largely on the Multiple 

Air Toxics Exposure Study III (MATES III), a monitoring and evaluation study 

conducted by AQMD between April 2004 and March 2006 to characterize the long-term 

carcinogenic risk from exposure to air toxics in the South Coast Air Basin. Timeintegrated (24-hr) measurements were taken for most of the pollutants measured, and 
71 

therefore a limitation of this study was that short-term exposures could not be assessed. 

The only near-continuous measurements available were UFP and CO, as well as some 

limited instantaneous VOC samples. The short-term VOC samples collected near the 

blast-fence area did show evidence of jet exhaust. Community members as well as 

AQMD staff have experienced short-term odors during nearby aircraft operations. As 

more advanced continuous instrumentation for measuring air toxics becomes available, 

future work could include an assessment of these short-term impacts and acute exposures. 

Future work may also include measurements of UFP levels and particle size distributions 

correlated to aircraft type and aircraft operations. 

ACKNOWLEDGEMENTS 

This study was conducted as part of a Community-Scale Air Toxics Ambient 

Monitoring Grant from the U.S. EPA. AQMD would like to thank Virginia Ernst and the 

Santa Monica Airport for their help and support in carrying out this study. We would also 

like to acknowledge the important contributions of the following individuals and 

organizations who provided valuable input to this effort: 

Airports Air Quality Study Advisory Committee

The Office of California State Assembly Member Fran Pavley 

The Office of Congressman Henry Waxman 

The Office of Congresswoman Jane Harman 

The Office of Congresswoman Maxine Waters 

Los Angeles City Councilman Bill Rosendahl 

Todd Campbell Coalition for Clean Air 

Gretchen Hardison Los Angeles City Department of Environmental Affairs 

Mike McDaniel Million Air Van Nuys 

Susan L. Mearns, Ph.D. Santa Monica Task Force on Environment 

Rod Merl Santa Monica Airport 

Martin Rubin Concerned Residents Against Airport Pollution 

Other Contributors

Los Angeles City Councilwoman Jan Perry 

California State Assembly Member Ted Lieu 

Brandon Eaton Los Angeles World Airports 

Ping Ho Friends of Sunset Park 

Brett Horner City of Santa Monica 

Christopher Patton Los Angeles City Department of Environmental Affairs 

Bill Piazza Los Angeles Unified School District 

Dennis Quilliam Los Angeles World Airports 

Cyrus Rangan, M.D. Los Angeles County Public Health Department 

Marty Tachiki City of Santa Monica Attorney 

Robert Trimborn Santa Monica Airport 

Lin Wang Los Angeles World Airports 
72 

REFERENCES 

Agrawal, H., Sawant, A.A., Jansen, K., Miller, J.W., and D.R. Cocker III (2008) 

Characterization of chemical and particulate emissions from aircraft engines, 

Atmospheric Environment 42: 4380–4392 

Aircraft Engine Speciated Organic Gases: Speciation of Unburned Organic Gases in 

Aircraft Exhaust, prepared by EPA in 2009 

Airborne Particulate Matter, Lead and Manganese at Buttonville Airport; prepared by 

Conor Pacific Environmental Technologies Inc. in 2000 

Arhami, M., Sillanpää, M., Hu, S., Geller, M.D., Schauer, J.J. and Sioutas, C. (2009) Sizesegregated Inorganic and Organic Components of PM In the Communities of the 

Long Angeles Harbor Across Southern Los Angeles Basin, California, Aerosol 

Science and Technology, 43(2), 145-160

Bastress, E.K. (1973) Impact of aircraft exhaust emissions at airports. Environmental 

Science & Technology, 7(9): 811-816 

Birmili, W., Allen, A.G., Bary, F., Harrison, R.M. (2006) Trace metal concentrations and 

water solubility in size-fractionated atmospheric particles and influence of road 

traffic, Environmental Science & Technology 40(4): 1144–1153 

Chicago O’Hare Airport Air Toxic Monitoring Program (2002) Prepared by the Illinois 

Environmental Protection Agency, Bureau of Air 

Cho A.K., Sioutas C., Schmitz, D.A., Kumagai Y., Singh M., Miguel A.H and Froines, 

J.R. (2005) Redox activity of airborne particulate matter (PM) at different sites in 

the Los Angeles Basin, Environmental Research, 99 (1): 40 - 47 

Delfino, R.J., Sioutas, C., Malik, S. (2005) Potential role of ultrafine particles in 

associations between airborne particle mass and cardiovascular health, 

Environmental Health Perspectives, 113(8): 934-946 

Dodson, R.E., Houseman, E.A., Morin, B., and Levy, J.I. (2009) An analysis of 

continuous black carbon concentrations in proximity to an airport and major 

roadways, Atmospheric Environment 43: 3764–3773 

ENVIRON Corp. (2008) Teterboro Airport, New Jersey, Detailed Air Quality Evaluation, 

Final Report Prepared for the New Jersey Department of Environmental 

Protection. 

Fanning, E., Yu, R.H., Lu, R., and Froines, J. (2007) Monitoring and Modeling of 

Ultrafine Particles and Black Carbon at the Los Angeles International Airport, 

Final Report Prepared for the California Air Resources Board and the California 

Environmental Protection Agency 

Federal Aviation Administration; http://www.faa.gov/regulations_policies/

Geller M.D., Ntziachristos L., Mamakos A., Samaras Z., Schmitz D.A., Froines J.R. and 

Sioutas, C. (2006) Physicochemical and Redox Characteristics of Particulate 
73 

Meter (PM) Emitted From Light Duty Gasoline and Diesel Passenger Cars, 

Atmospheric Environment, 40:6988–7004 

Groma, V., Osan, J., Torok, S., Meirer, F., Streli, C., Wobrauscbek, P., and Falkenberg, 

G. (2008) Trace element analysis of airport related aerosols using SR-TXRF, 

IDOJARAS, 112(2): 83-97 

Hermann, M., Wehner, B., Bischof, O., Han, H.S., Krinke, T., Liu, W., Zerrath, A. and 

Wiedensohler, A. (2007) Particle counting efficiencies of new TSI condensation 

particle counters, Aerosol Science 38: 674–682 

Herndon, S.C., Onasch, T.B., Frank, B.P., Marr, L.C., Jayne, J.T., Canagaratna, M.R., 

Grygas, J., Lanni, T., Anderson, B.E., Worsnop, D., and Miake-Lye, R.C. (2005) 

Particulate Emissions from in-use Commercial Aircraft, Aerosol Science and 

Technology, (39):799–809 

Herndon, S.C., Rogers, T., Dunlea, E.J., Jayne, J.T., Miake-Lye, R., and Knighton, B. 

(2006) hydrocarbon emissions from in-use commercial aircraft during airport 

operations, Environmental Science & Technology, 40(14): 4406-4413 

Herndon, S.C., Jayne, J.T., Lobo, P., Onasch, T.B., Fleming, G., Hagen, D.E., Whitefield, 

P.D. and Miake-Lye, R.C. (2008) Commercial aircraft engine emissions 

characterization of in-use aircraft at Hartsfield-Jackson Atlanta International 

Airport, Environmental Science and Technology, 42(6):1877-1883 

Herndon, S.C., Wood, E.C., Northway, M.J., Miake-Lye, R., Thornhill, L., Beyersdorf, 

A., Anderson, B.E., Dowlin, R., Dodds, W., and Knighton, W.B. (2009) Aircraft 

Hydrocarbon Emissions at Oakland International Airport, Environmental Science 

and Technology, 43: 1730-1736 

http://epa.gov/oms/aviation.htm

http://www.apo.data.faa.gov/main/taf.asp

Hu, S., Fruin, S., Kozawa, K., Mara, S., Winer, A.M., and Paulson (2009) S.E. Aircraft 

Emission Impacts in a Neighborhood Adjacent to a General Aviation Airport in 

Southern California. Environmental Science & Technology, 43: 8039–8045 

International Civil Aviation Organization (ICAO) Aircraft Engine Emissions DataBank 

(2006), http://www.caa.co.uk/docs/702/introduction-05102004.pdf 

Lelievre, C.P., Magnani, G.,Ramaroson, R., Gouriou, F., Talbaut, M., Frejafon, E., 

Schuermann, G., Schaefer, K., Cornier, I., Emeis, S., Vannier, F., Paux, E., 

Copalle, A., and Perros, P. (2006) Air quality and engine emission at Paris CDG 

airport during AIRPUR field campaigns, Air Pollution XIV, 86: 261-276 

Lobo, P., Hagen, D.E., Whitefield, P.D., and Alofs, D.J. (2007) Physical characterization 

of aerosol emissions from a Commercial Gas Turbine Engine, Journal of 

Propulsion and Power, 23: 919-929 

Mordas, G., Manninen H.E., Petäjä, T., Aalto, P.P., Hämeri, K., and Kulmala M. (2008) 

On Operation of the Ultra-Fine Water-Based CPC TSI 3786 and Comparison with 

Other TSI Models (TSI 3776, TSI 3772, TSI 3025, TSI 3010, TSI 3007), Aerosol 

Science and Technology, 42:152–158, 2008 
74 

Nel, A., Xia, T., Madler, L., and Li, N. (2006) Toxic potential of materials at the nanolevel. Science, 311 (5761): 622–627 

Ntziachristos, L., Froines, J.R., Cho, A.K., and Sioutas, C. (2007a) Relationship between 

redox activity and chemical speciation of size-fractionated particulate matter, 

Particle and Fibre Toxicology, DOI:10.1186/1743-8977-4-5 

Ntziachristos L., Ning Z., Geller M.D., Sheesley R.J., Schauer J.J., Sioutas C., Fine P. 

(2007b) Ultrafine and nanoparticle trace element compositions near a major 

freeway with a high heavy-duty diesel fraction, Atmospheric Environment, 41 

(27), 5684-5696 

Onasch, T.B., Jayne, J.T., Herndon, S.C., Mortimer, P., Worsnop, D.R., and Miake-Lye, 

R.C. (2006) Chemical Properties of Aircraft Engine Exhaust Aerosols Sampled 

During APEX, NASA/TM-2006-214382 ARL_TR_3903: Appendix J 

ORGPROF; http://www.arb.ca.gov/ei/speciate/speciate.htm 

Petzold, A., Fiebig, M., Fritzsche, L., Stein, C., Schumann, U., Wilson, C.W., Hurley, 

C.D., Arnold, F., Katragkou, E., Baltensperger, U., Gysela, M., Nyeki, S., 

Hitzenberger, R., Giebel, H., Hughes, K.J., Kurtenbach, R., Wisen, P., Madden, 

P., Puxbaum, H., Vrchotickt, S. and WAHL, C. (2005) Particle emissions from 

aircraft engines – a survey of the European project PartEmis, Meteorologische 

Zeitschrift, Vol. 14, No. 4, 465-476 

Pope, A., Dockery, D.W. (2006) Health Effects of Fine Particulate Air Pollution: Lines 

that Connect, Journal of the Air & Waste Management Association, 56:709–742 

Rogers, F., Arnott, P., Zielinska, B., Sagebiel, J., Kelly, K.E., Wagner, D., Lighty, J.S., 

and Sarofim, A.F. (2005) Real-Time Measurement of Jet Aircraft Engine Exhaust, 

Journal of the Air & Waste Management Association, 55 583-593 

Sanders, P.G., Xu, N., Dalka, T.M., and Maricq, M.M. (2003) Airborne Brake Wear 

Debris: Size Distributions, Composition, and a Comparison of Dynamometer and 

Vehicle Tests, Environmental Science & Technology, 37:4060–4069 

Schurmann, G., Schäfer, K., Jahn, C., Hoffmann, H., Groma, V., Török, S., and Emeis, S. 

(2006) Airport air quality and emission studies by remote sensing and inverse 

dispersion modeling, Remote Sensing of Clouds and the Atmosphere XI, 6362: 

U370-U381 

Schurmann, G., Schafer, K., Jahn, C., Hoffmann, H., Bauerfeind, M., Fleuti, E., and 

Rappengluck, B. (2007) The impact of NOx, CO and VOC emissions on the air 

quality of Zurich airport, Atmospheric Environment, 41(1): 103-118 

Singh, M., Jaques, P.A., and Sioutas, C. (2002) Size distribution and diurnal 

characteristics of particle-bound metals in source and receptor sites of the Los 

Angeles Basin. Atmospheric Environment 36: 1675–1689 

Sioutas, C., Delfino, R.J., Singh, M. (2005) Exposure assessment for atmospheric 

ultrafine particles (UFPs) and implications in epidemiologic research, 

Environmental Health Perspectives, 113(8): 947-955 
75 

South Air Quality Management District (1998) Air Monitoring Study at Los Angeles 

International Airport 

South Coast Air Quality Management District (2000a) Air Monitoring Study in the Area 

of Los Angeles International Airport 

South Coast Air Quality Management District (2000b) Inglewood Particulate fallout 

Study Under and Near the Flight Path to Los Angeles International Airport 

South Coast Air Quality Management District (2000c) Multiple Air Toxics Exposure 

Study (MATES II) 

South Coast Air Quality Management District (2001) Air Monitoring Study at Felton and 

Lloyde Schools 

South Coast Air Quality Management District (2008) Multiple Air Toxics Exposure 

Study (MATES III) 

Spicer, C.W., Holdren, M.W., Lyon, T.F., and Riggin, R.M. (1984) Composition and 

Photochemical Reactivity of Turbine Engine Exhaust, USAF (Report No. ESL-TR84-28) 

Spicer, C.W., Holdren, M.W., Smith, D.L., Hughes, D.P., and Smith, M.D. (1992) 

Chemical Composition of Exhaust Aircraft Turbine Engines, Journal of 

Engineering for Gas Turbines and Power, 114(1): 111-117 

Spicer, C.W., Holdren, M.W., Riggin, R.M., and Lyon, T.F. (1994) Chemical 

Composition and Photochemical Reactivity of Exhaust from Aircraft Turbine 

Engines, Annales Geophysicae-Atmospheres Hydrospheres and Space Science, 

12(10-11): 944-955 

U.S. EPA (2003) National Emission Trends, Average Annual Emissions, All Criteria 

Pollutants, 1970-2001; www.epa.gov/ttn/chief/trends/index.html 

U.S. EPA (2003) Average Annual Emissions, All Criteria Pollutants Years Including 

1980, 1985, 1989–2001 

U.S. EPA (2005) Documentation for Aircraft, Commercial Marine Vessel, Locomotive, 

and other Non-Road Compnents of the National Emission Inventroy, Vol. I 

U.S. EPA (2008) Lead Emissions from the Use of Leaded Aviation Gasoline in the 

United States 

U.S. EPA (2009) Aircraft Engine Speciated Organic Gases: Speciation of Unburned 

Organic Gases in Aircraft Exhaust 

U.S. EPA, (2010) Development and Evaluation of an Air Quality Modeling Approach for 

Lead Emissions from Piston-Engine Aircraft Operating on Leaded Aviation 

Gasoline 

Westerdahl, D., Fruin, S.A., Fine, P.M., and Sioutas, C. (2008) The Los Angeles 

International Airport as a source of ultrafine particles and other pollutants to 

nearby communities, Atmospheric Environment (42), 3143–3155 

Wey, C.C. (2004) Overview of the Aircraft Particle Emissions eXperiment (APEX) 

Program, Aircraft Particle Emissions Workshop, Cleveland, OH 
76 

Wey, C.C., Anderson, B.E. et al. (2006) Aircraft Particle Emissions eXperiment (APEX), 

NASA/TM-2006-214382; ARL-TR-3903; NASA: Washington, DC. 

Xia, T., Korge, P., Weiss, J.N., Li, N., Venkatesen, M.I., Sioutas, C., Nel, A. (2004) 

Quinones and aromatic chemical compounds in particulate matter (PM) induce 

mitochondrial dysfunction: implications for ultrafine particle toxicity, 

Environmental Health Perspectives 112 (14), 1347–1358 

Yu, K.N., Cheung, Y.P., Cheung, T., and Henry, R.C (2004) Identifying the impact of 

large urban airports on local air quality by nonparametric regression, Atmospheric 

Environment, 38: 4501–4507 

Zhu, Y.F., Hinds, W.C., Kim, S., Shen, S., Sioutas, C. (2002a) Study of ultrafine particles 

near a major highway with heavy-duty diesel traffic Author, Atmospheric 

Environment, 36(27): 4323-4335 

Zhu, Y.F., Hinds, W.C., Kim, S., and Sioutas, C. (2002b) Concentration and size 

distribution of ultrafine particles near a major highway, Journal of the Air & 

Waste Management Association, 52(9): 1032-1042 
77 

APPENDIX A 
Table A1 Average and median 1,3-butadiene, methylene chloride, and chloroform 

concentrations (ppb) at the Van Nuys Airport during Phase 1 (November 2005 - March 

2006) and Phase 2 (July - September, 2006). Minimum (Min) and maximum (Max) 

values, standard deviations (SD), and the total number of valid samples (Valid N) have 

also been reported for each species along with the corresponding values from a 

companion monitoring station in Burbank (in red). Concentrations reported as 0.00 ppb 

represent non detected (ND) values. 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard Burbank 

1,3-Butadiene (ppb) - Phase 1 

Average 0.16 0.09 0.16 N/A 0.23 

Median 0.09 0.05 0.10 N/A 0.19 

SD 0.14 0.10 0.15 N/A 0.17 

Min 0.00 0.00 0.00 N/A 0.00 

Max 0.44 0.41 0.52 N/A 0.62 

Valid N 29 25 30 N/A 30 

1,3-Butadiene (ppb) - Phase 2 

Average 0.05 0.01 0.05 0.06 0.06 

Median 0.05 0.01 0.04 0.05 0.05 

SD 0.03 0.01 0.04 0.04 0.05 

Min 0.01 0.00 0.01 0.01 0.01 

Max 0.13 0.02 0.15 0.18 0.23 

Valid N 20 4 20 14 20 

Methylene Chloride (ppb) - Phase 1 

Average 0.25 0.21 0.25 N/A 0.42 

Median 0.17 0.16 0.24 N/A 0.35 

SD 0.18 0.20 0.20 N/A 0.49 

Min 0.04 0.00 0.00 N/A 0.03 

Max 0.67 0.87 0.70 N/A 2.81 

Valid N 29 25 30 N/A 30 

Methylene Chloride (ppb) - Phase 2

Average 0.19 0.13 0.21 0.25 0.26 

Median 0.20 0.11 0.21 0.25 0.28 

SD 0.09 0.07 0.09 0.09 0.13 

Min 0.06 0.08 0.08 0.12 0.08 

Max 0.43 0.24 0.39 0.46 0.67 

Valid N 20 4 20 14 20 

Chloroform (ppb) - Phase 1

Average 0.07 0.05 0.05 N/A 0.06 

Median 0.06 0.05 0.05 N/A 0.06 

SD 0.04 0.03 0.04 N/A 0.03 

Min 0.00 0.01 0.00 N/A 0.01 

Max 0.14 0.12 0.13 N/A 0.11 

Valid N 29 25 30 N/A 30 

Chloroform (ppb) - Phase 2

Average 0.13 0.06 0.09 0.11 0.06 

Median 0.13 0.04 0.10 0.10 0.06 

SD 0.07 0.04 0.05 0.06 0.03 

Min 0.03 0.04 0.02 0.03 0.02 

Max 0.23 0.13 0.18 0.22 0.15 

Valid N 20 4 20 14 20 

78 
Table A2 Average and median benzene, carbon tetrachloride, and toluene concentrations 

(ppb) at the Van Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 

2 (July - September, 2006). Minimum (Min) and maximum (Max) values, standard 

deviations (SD), and the total number of valid samples (Valid N) have also been reported 

for each species along with the corresponding values from a companion monitoring 

station in Burbank (in red). Concentrations reported as 0.00 ppb represent non detected 

(ND) values. 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard Burbank 

Benzene (ppb) - Phase 1 

79 

Average 1.05 0.57 0.80 N/A 1.08 

Median 0.95 0.46 0.63 N/A 1.21 

SD 0.69 0.53 0.86 N/A 0.52 

Min 0.15 0.10 0.11 N/A 0.11 

Max 3.03 2.71 4.66 N/A 1.85 

Valid N 29 25 30 N/A 30 

Benzene (ppb) - Phase 2 

Average 0.39 0.20 0.38 0.45 0.43 

Median 0.40 0.16 0.39 0.43 0.46 

SD 0.19 0.09 0.18 0.20 0.20 

Min 0.15 0.13 0.16 0.20 0.17 

Max 0.90 0.34 0.93 1.07 0.98 

Valid N 20 4 20 14 20 

Carbon Tetrachloride (ppb) - Phase 1 

Average 0.09 0.08 0.08 N/A 0.09 

Median 0.09 0.09 0.09 N/A 0.09 

SD 0.02 0.02 0.02 N/A 0.01 

Min 0.03 0.00 0.00 N/A 0.06 

Max 0.13 0.11 0.11 N/A 0.10 

Valid N 29 25 30 N/A 30 

Carbon Tetrachloride (ppb) - Phase 2

Average 0.08 0.08 0.08 0.09 0.08 

Median 0.08 0.08 0.08 0.09 0.08 

SD 0.01 0.01 0.01 0.01 0.01 

Min 0.05 0.07 0.06 0.06 0.07 

Max 0.10 0.09 0.10 0.10 0.10 

Valid N 20 4 20 14 20 

Toluene (ppb) - Phase 1

Average 3.85 1.28 1.98 N/A 3.76 

Median 3.88 1.26 1.67 N/A 4.20 

SD 2.58 0.98 1.60 N/A 2.10 

Min 0.31 0.12 0.14 N/A 0.17 

Max 10.2 3.27 4.85 N/A 6.83 

Valid N 29 25 30 N/A 30 

Toluene (ppb) - Phase 2

Average 1.22 0.56 1.15 1.43 1.87 

Median 1.28 0.38 1.04 1.43 1.43 

SD 0.61 0.40 0.66 0.72 1.50 

Min 0.31 0.30 0.34 0.43 0.48 

Max 3.03 1.15 2.89 3.36 6.46 

Valid N 20 4 20 14 20 
Table A3 Average and median perchloroethylene concentrations (ppb) at the Van Nuys 

Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - September, 

2006). Minimum (Min) and maximum (Max) values, standard deviations (SD), and the 

total number of valid samples (Valid N) have also been reported for each species along 

with the corresponding values from a companion monitoring station in Burbank (in red). 

Concentrations reported as 0.00 ppb represent non detected (ND) values. 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard Burbank 

Perchloroethylene (ppb) - Phase 1 

Average 0.10 0.04 0.05 N/A 0.15 

Median 0.07 0.03 0.04 N/A 0.13 

SD 0.09 0.04 0.05 N/A 0.15 

Min 0.00 0.00 0.00 N/A 0.00 

Max 0.32 0.12 0.15 N/A 0.79 

Valid N 29 25 30 N/A 30 

Perchloroethylene (ppb) - Phase 2 

Average 0.05 0.03 0.05 0.08 0.07 

Median 0.06 0.03 0.05 0.07 0.07 

SD 0.03 0.02 0.03 0.05 0.03 

Min 0.01 0.01 0.01 0.01 0.02 

Max 0.11 0.06 0.13 0.21 0.16 

Valid N 20 4 20 14 20 

80 
Table A4 Average and median 1,3-butadiene, methylene chloride, and chloroform 

concentrations (ppb) at the Santa Monica Airport during Phase 1 (April - July, 2006) and 

Phase 2 (October 2006 - February 2007). Minimum (Min) and maximum (Max) values, 

standard deviations (SD), and the total number of valid samples (Valid N) have also been 

reported for each species along with the corresponding values from a companion 

monitoring station in Central Los Angeles (in red). Concentrations reported as 0.00 ppb 

represent non detected (ND) values. 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

Central Los 

Angeles 

1,3-Butadiene (ppb) - Phase 1

Average 0.01 0.01 0.02 0.02 0.01 0.02 

Median 0.00 0.00 0.00 0.00 0.00 0.00 

SD 0.03 0.02 0.02 0.03 0.02 0.03 

Min 0.00 0.00 0.00 0.00 0.00 0.00 

Max 0.09 0.08 0.06 0.07 0.10 0.11 

Valid N 24 19 16 9 24 20 

1,3-Butadiene (ppb) - Phase 2

Average 0.13 0.08 0.14 0.12 0.09 0.14 

Median 0.12 0.07 0.13 0.11 0.08 0.13 

SD 0.09 0.06 0.08 0.08 0.06 0.08 

Min 0.00 0.00 0.00 0.02 0.00 0.00 

Max 0.42 0.24 0.35 0.32 0.31 0.31 

Valid N 41 21 43 24 44 39 

Methylene Chloride (ppb) – Phase 1

Average 0.18 0.13 0.18 0.25 0.18 0.33 

Median 0.18 0.12 0.18 0.15 0.14 0.33 

SD 0.11 0.08 0.09 0.29 0.12 0.11 

Min 0.00 0.00 0.05 0.01 0.00 0.15 

Max 0.39 0.36 0.37 0.97 0.55 0.53 

Valid N 24 19 16 9 24 20 

Methylene Chloride (ppb) - Phase 2

Average 0.28 0.22 0.27 0.20 0.25 0.41 

Median 0.25 0.16 0.24 0.16 0.24 0.38 

SD 0.16 0.12 0.15 0.11 0.15 0.19 

Min 0.07 0.07 0.07 0.06 0.07 0.10 

Max 0.85 0.44 0.84 0.44 0.82 0.84 

Valid N 41 21 43 24 44 39 

Chloroform (ppb) - Phase 1

Average 0.03 0.04 0.05 0.05 0.03 0.03 

Median 0.03 0.05 0.05 0.05 0.03 0.04 

SD 0.02 0.02 0.02 0.03 0.02 0.03 

Min 0.00 0.00 0.02 0.02 0.00 0.00 

Max 0.07 0.10 0.09 0.10 0.06 0.08 

Valid N 24 19 16 9 24 20 

Chloroform (ppb) - Phase 2

Average 0.07 0.06 0.07 0.05 0.05 0.05 

Median 0.07 0.06 0.07 0.04 0.05 0.05 

SD 0.03 0.02 0.03 0.02 0.02 0.02 

Min 0.01 0.03 0.03 0.01 0.01 0.03 

Max 0.14 0.12 0.13 0.10 0.10 0.12 

Valid N 41 21 43 24 44 39 

81 
Table A5 Average and median benzene, carbon tetrachloride, and toluene concentrations 

(ppb) at the Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 

(October 2006 - February 2007). Minimum (Min) and maximum (Max) values, standard 

deviations (SD), and the total number of valid samples (Valid N) have also been reported 

for each species along with the corresponding values from a companion monitoring 

station in Central Los Angeles (in red). 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

Central Los 

Angeles 

Benzene (ppb) - Phase 1

Average 0.27 0.21 0.30 0.29 0.23 0.46 

Median 0.23 0.15 0.22 0.30 0.19 0.47 

SD 0.21 0.17 0.25 0.18 0.15 0.18 

Min 0.10 0.06 0.10 0.09 0.10 0.19 

Max 1.15 0.78 1.17 0.59 0.82 0.82 

Valid N 24 19 16 9 24 20 

Benzene (ppb) - Phase 2

Average 0.62 0.46 0.64 0.52 0.50 0.66 

Median 0.60 0.43 0.60 0.41 0.49 0.65 

SD 0.31 0.21 0.31 0.28 0.25 0.28 

Min 0.16 0.17 0.19 0.17 0.14 0.20 

Max 1.52 0.93 1.58 1.16 1.38 1.31 

Valid N 41 21 43 24 44 39 

Carbon Tetrachloride (ppb) - Phase 1

Average 0.09 0.09 0.09 0.11 0.09 0.09 

Median 0.09 0.09 0.09 0.10 0.09 0.09 

SD 0.01 0.03 0.01 0.03 0.01 0.02 

Min 0.08 0.06 0.07 0.09 0.07 0.06 

Max 0.11 0.18 0.12 0.17 0.11 0.12 

Valid N 24 19 16 9 24 20 

Carbon Tetrachloride (ppb) - Phase 2

Average 0.09 0.09 0.09 0.09 0.09 0.09 

Median 0.09 0.09 0.08 0.09 0.09 0.09 

SD 0.02 0.02 0.01 0.01 0.01 0.01 

Min 0.06 0.07 0.06 0.06 0.06 0.06 

Max 0.16 0.14 0.14 0.12 0.15 0.11 

Valid N 41 21 43 24 44 39 

Toluene (ppb) - Phase 1

Average 0.71 0.55 0.81 0.80 0.66 1.33 

Median 0.67 0.45 0.82 0.62 0.60 1.31 

SD 0.30 0.30 0.24 0.42 0.35 0.52 

Min 0.25 0.19 0.43 0.33 0.26 0.62 

Max 1.59 1.53 1.36 1.48 1.75 2.64 

Valid N 24 19 16 9 24 20 

Toluene (ppb) - Phase 2

Average 1.82 1.31 1.96 1.63 1.53 2.05 

Median 1.80 1.06 1.94 1.23 1.46 2.09 

SD 1.07 0.81 1.07 1.24 0.90 0.95 

Min 0.26 0.36 0.36 0.29 0.21 0.49 

Max 4.82 3.19 4.67 4.70 3.88 4.33 

Valid N 41 21 43 24 44 39 

82 
Table A6 Average and median trichloroethene and perchloroethylene concentrations 

(ppb) at the Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 

(October 2006 - February 2007). Minimum (Min) and maximum (Max) values, standard 

deviations (SD), and the total number of valid samples (Valid N) have also been reported 

for each species along with the corresponding values from a companion monitoring 

station in Central Los Angeles (in red). Concentrations reported as 0.00 ppb represent 

non detected (ND) values. 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

Central Los 

Angeles 

Trichloroethene (ppb) - Phase 1

Average 0.00 0.00 0.01 0.01 0.00 0.02 

Median 0.00 0.00 0.00 0.00 0.00 0.01 

SD 0.00 0.01 0.01 0.02 0.00 0.03 

Min 0.00 0.00 0.00 0.00 0.00 0.00 

Max 0.01 0.03 0.02 0.05 0.01 0.10 

Valid N 24 19 16 9 24 20 

Trichloroethene (ppb) - Phase 2

Average 0.01 0.01 0.03 0.02 0.01 0.02 

Median 0.01 0.00 0.02 0.02 0.00 0.02 

SD 0.02 0.01 0.02 0.02 0.01 0.02 

Min 0.00 0.00 0.00 0.00 0.00 0.00 

Max 0.07 0.05 0.08 0.06 0.06 0.09 

Valid N 40 21 43 24 43 39 

Perchloroethylene (ppb) - Phase 1

Average 0.03 0.02 0.02 0.05 0.02 0.05 

Median 0.03 0.02 0.02 0.03 0.02 0.06 

SD 0.03 0.02 0.02 0.04 0.02 0.03 

Min 0.00 0.00 0.00 0.00 0.00 0.00 

Max 0.09 0.07 0.05 0.12 0.07 0.13 

Valid N 24 19 16 9 24 20 

Perchloroethylene (ppb) - Phase 2

Average 0.13 0.07 0.10 0.08 0.08 0.09 

Median 0.10 0.06 0.09 0.08 0.07 0.08 

SD 0.13 0.06 0.08 0.08 0.06 0.09 

Min 0.00 0.00 0.00 0.00 0.00 0.00 

Max 0.72 0.25 0.34 0.36 0.32 0.53 

Valid N 41 21 43 24 44 39 

83 
84 

Table A7 Average 8-hr VOC concentrations (ppb) at the Van Nuys Airport during Phase 

1 (November 2005 - March 2006). The corresponding percentage contributions to their 

total daily levels have also been included 

Van Nuys Airport - Phase 1

Concentration (ppb) Percentage Contribution

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

1,3-Butadiene 

GOLF COURSE 

0.22 0.11 0.15 45.4% 23.0% 31.6% 

Benzene 1.28 0.86 1.03 40.3% 27.2% 32.5% 

Carbon Tetrachloride 0.09 0.09 0.09 34.2% 32.6% 33.2% 

Chloroform 0.11 0.05 0.06 48.7% 22.0% 29.3% 

Methylene Chloride 0.34 0.20 0.20 46.3% 26.7% 27.1% 

Perchloroethylene 0.12 0.07 0.10 41.8% 24.4% 33.8% 

Toluene 5.11 2.82 3.72 43.8% 24.2% 32.0% 

Trichloroethene 0.02 0.06 0.07 15.1% 39.0% 45.8% 

1,3-Butadiene 

HOLMES 

SCHOOL 

0.10 0.06 0.12 37.1% 20.5% 42.3% 

Benzene 0.63 0.49 0.60 36.7% 28.4% 34.9% 

Carbon Tetrachloride 0.08 0.08 0.09 32.7% 33.0% 34.4% 

Chloroform 0.07 0.03 0.06 45.7% 19.0% 35.3% 

Methylene Chloride 0.20 0.21 0.22 30.8% 33.7% 35.5% 

Perchloroethylene 0.04 0.04 0.04 33.7% 34.7% 31.6% 

Toluene 1.37 1.04 1.45 35.4% 27.0% 37.6% 

Trichloroethene 0.00 0.04 0.04 4.5% 51.1% 44.4% 

1,3-Butadiene 

VOR 

0.19 0.10 0.19 38.8% 21.7% 39.5% 

Benzene 0.92 0.63 0.88 38.1% 25.8% 36.1% 

Carbon Tetrachloride 0.08 0.09 0.08 33.3% 33.9% 32.7% 

Chloroform 0.07 0.03 0.05 45.8% 20.4% 33.8% 

Methylene Chloride 0.31 0.21 0.24 41.2% 27.5% 31.2% 

Perchloroethylene 0.06 0.05 0.05 38.6% 31.8% 29.6% 

Toluene 2.28 1.49 2.25 37.9% 24.7% 37.4% 

Trichloroethene 0.10 0.05 0.06 47.2% 24.0% 28.8% 
Table A8 Average 8-hr VOC concentrations (ppb) at the Van Nuys Airport during Phase 

2 (July - September 2006). The corresponding percentage contributions to their total daily 

levels have also been included 

Van Nuys Airport - Phase 2

Concentration (ppb) Percentage Contribution

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

1,3-Butadiene 

GOLF COURSE 

0.08 0.02 0.04 56.3% 16.2% 27.5% 

Benzene 0.54 0.33 0.28 46.9% 29.0% 24.2% 

Carbon Tetrachloride 0.09 0.09 0.07 34.7% 35.1% 30.1% 

Chloroform 0.24 0.06 0.07 65.3% 15.1% 19.6% 

Methylene Chloride 0.24 0.18 0.13 44.3% 32.3% 23.4% 

Perchloroethylene 0.06 0.06 0.04 39.4% 37.9% 22.7% 

Toluene 1.89 0.97 0.71 52.9% 27.2% 19.9% 

Trichloroethene 0.00 0.01 0.00 32.0% 48.0% 20.0% 

1,3-Butadiene 

HOLMES 

SCHOOL 

0.01 0.01 0.01 37.5% 37.5% 25.0% 

Benzene 0.24 0.16 0.16 42.4% 28.4% 29.1% 

Carbon Tetrachloride 0.08 0.08 0.08 33.1% 34.7% 32.2% 

Chloroform 0.10 0.03 0.04 56.3% 19.5% 24.1% 

Methylene Chloride 0.15 0.12 0.10 40.4% 32.2% 27.3% 

Perchloroethylene 0.03 0.03 0.02 40.0% 37.5% 22.5% 

Toluene 0.74 0.39 0.40 48.4% 25.6% 26.0% 

Trichloroethene 0.00 0.01 0.00 25.0% 75.0% 0.0% 

1,3-Butadiene 

NATIONAL 

GUARD 

0.09 0.04 0.04 49.8% 25.7% 24.5% 

Benzene 0.58 0.39 0.30 45.4% 30.8% 23.7% 

Carbon Tetrachloride 0.09 0.08 0.09 33.9% 32.3% 33.8% 

Chloroform 0.19 0.08 0.04 60.9% 24.7% 14.4% 

Methylene Chloride 0.33 0.22 0.18 45.4% 30.3% 24.3% 

Perchloroethylene 0.09 0.09 0.06 36.4% 38.1% 25.5% 

Toluene 2.11 1.11 0.86 51.8% 27.2% 21.0% 

Trichloroethene 0.01 0.01 0.01 48.5% 29.0% 22.5% 

1,3-Butadiene 

VOR 

0.08 0.03 0.05 51.7% 16.1% 32.2% 

Benzene 0.52 0.27 0.32 47.0% 24.4% 28.6% 

Carbon Tetrachloride 0.08 0.08 0.08 34.9% 33.0% 32.1% 

Chloroform 0.17 0.04 0.05 63.9% 16.5% 19.6% 

Methylene Chloride 0.25 0.19 0.16 42.0% 31.6% 26.4% 

Perchloroethylene 0.07 0.06 0.03 43.4% 36.6% 20.0% 

Toluene 1.74 0.72 0.82 52.9% 21.9% 25.1% 

Trichloroethene 0.01 0.00 0.00 50.8% 25.4% 23.7% 

85 
Table A9 Average 8-hr VOC concentrations (ppb) at the Santa Monica Airport during 

Phase 1 (April - July, 2006). The corresponding percentage contributions to their total 

daily levels have also been included 

Santa Monica Municipal Airport - Phase 1

Concentration (ppb) Percentage Contribution

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

1,3-Butadiene 

EAST TARMAC 

0.01 0.02 0.04 21.1% 26.3% 52.6% 

Benzene 0.39 0.27 0.16 47.7% 32.8% 19.4% 

Carbon Tetrachloride 0.11 0.10 0.10 37.1% 31.2% 31.7% 

Chloroform 0.09 0.04 0.03 58.9% 23.9% 17.3% 

Methylene Chloride 0.26 0.25 0.06 45.6% 43.6% 10.9% 

Perchloroethylene 0.06 0.03 0.01 57.2% 30.7% 12.1% 

Toluene 0.96 0.81 0.44 43.2% 36.8% 20.0% 

Trichloroethene 0.02 0.01 0.01 56.0% 23.3% 20.7% 

1,3-Butadiene 

WEST TARMAC 

0.02 0.00 0.00 73.8% 12.3% 13.8% 

Benzene 0.36 0.17 0.18 51.0% 23.6% 25.4% 

Carbon Tetrachloride 0.09 0.09 0.09 32.6% 33.7% 33.7% 

Chloroform 0.04 0.02 0.02 52.5% 19.4% 28.1% 

Methylene Chloride 0.20 0.19 0.14 37.2% 35.7% 27.0% 

Perchloroethylene 0.05 0.01 0.01 68.0% 21.6% 10.4% 

Toluene 1.18 0.39 0.46 58.0% 19.4% 22.5% 

Trichloroethene 0.00 0.00 0.00 30.9% 49.4% 19.7% 

1,3-Butadiene 

ERNST 

RESIDENCE 

0.01 0.02 0.02 22.8% 40.6% 36.5% 

Benzene 0.42 0.28 0.19 46.9% 31.3% 21.9% 

Carbon Tetrachloride 0.09 0.09 0.09 33.3% 32.5% 34.2% 

Chloroform 0.07 0.04 0.05 45.5% 23.6% 30.9% 

Methylene Chloride 0.20 0.27 0.08 36.1% 49.9% 14.0% 

Perchloroethylene 0.02 0.02 0.01 38.0% 40.6% 21.4% 

Toluene 1.04 0.80 0.59 42.8% 32.8% 24.4% 

Trichloroethene 0.01 0.00 0.00 78.1% 17.5% 4.4% 

1,3-Butadiene 

MARINE PARK 

0.03 0.01 0.00 72.7% 15.3% 12.0% 

Benzene 0.34 0.15 0.12 55.3% 24.5% 20.1% 

Carbon Tetrachloride 0.09 0.11 0.08 32.5% 38.7% 28.8% 

Chloroform 0.07 0.03 0.03 52.4% 21.7% 26.0% 

Methylene Chloride 0.21 0.12 0.07 52.8% 29.6% 17.6% 

Perchloroethylene 0.05 0.02 0.01 62.4% 22.0% 15.6% 

Toluene 0.98 0.36 0.30 59.8% 22.0% 18.2% 

Trichloroethene 0.00 0.01 0.00 25.0% 70.0% 5.0% 

1,3-Butadiene 

RICHLAND 

SCHOOL 

0.03 0.01 0.01 63.4% 16.4% 20.2% 

Benzene 0.44 0.21 0.18 53.2% 25.1% 21.7% 

Carbon Tetrachloride 0.09 0.09 0.09 34.4% 32.4% 33.2% 

Chloroform 0.06 0.02 0.02 59.1% 19.2% 21.7% 

Methylene Chloride 0.21 0.22 0.10 39.0% 41.5% 19.5% 

Perchloroethylene 0.06 0.03 0.02 54.7% 28.2% 17.1% 

Toluene 1.13 0.55 0.47 52.8% 25.5% 21.7% 

Trichloroethene 0.00 0.00 0.00 58.2% 41.8% 0.0% 

86 
Table A10 Average 8-hr VOC concentrations (ppb) at the Santa Monica Airport during 

Phase 2 (October 2006 - February 2007). The corresponding percentage contributions to 

their total daily levels have also been included 

Santa Monica Municipal Airport - Phase 2

Concentration (ppb) Percentage Contribution

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

00:00 

08:00 

08:00 

16:00 

16:00 

00:00 

1,3-Butadiene 

EAST TARMAC 

0.12 0.11 0.14 33.5% 29.2% 37.3% 

Benzene 0.56 0.46 0.52 36.5% 29.9% 33.6% 

Carbon Tetrachloride 0.09 0.09 0.08 34.0% 33.7% 32.2% 

Chloroform 0.07 0.04 0.04 44.3% 27.4% 28.3% 

Methylene Chloride 0.24 0.22 0.15 39.2% 35.8% 25.0% 

Perchloroethylene 0.11 0.09 0.05 44.7% 35.5% 19.8% 

Toluene 1.66 1.40 1.68 35.0% 29.5% 35.5% 

Trichloroethene 0.04 0.01 0.01 57.9% 20.8% 21.3% 

1,3-Butadiene 

WEST TARMAC 

0.12 0.05 0.12 40.4% 18.7% 40.9% 

Benzene 0.52 0.40 0.57 34.8% 26.9% 38.3% 

Carbon Tetrachloride 0.09 0.09 0.09 33.8% 33.6% 32.6% 

Chloroform 0.06 0.04 0.04 42.5% 26.6% 30.9% 

Methylene Chloride 0.28 0.26 0.22 37.1% 34.1% 28.8% 

Perchloroethylene 0.10 0.07 0.06 42.9% 30.5% 26.6% 

Toluene 1.73 1.09 1.80 37.5% 23.6% 38.9% 

Trichloroethene 0.01 0.01 0.01 46.0% 24.1% 29.9% 

1,3-Butadiene 

ERNST 

RESIDENCE 

0.18 0.10 0.16 40.5% 22.3% 37.2% 

Benzene 0.77 0.49 0.70 39.3% 24.9% 35.8% 

Carbon Tetrachloride 0.09 0.09 0.09 33.4% 33.3% 33.3% 

Chloroform 0.10 0.04 0.06 48.3% 21.3% 30.4% 

Methylene Chloride 0.34 0.26 0.23 41.0% 31.6% 27.4% 

Perchloroethylene 0.15 0.10 0.07 46.7% 30.2% 23.1% 

Toluene 2.41 1.47 2.14 40.1% 24.4% 35.5% 

Trichloroethene 0.05 0.01 0.02 58.8% 14.4% 26.8% 

1,3-Butadiene 

MARINE PARK 

0.11 0.05 0.12 40.2% 17.5% 42.3% 

Benzene 0.55 0.38 0.55 37.1% 25.5% 37.4% 

Carbon Tetrachloride 0.09 0.09 0.09 34.0% 33.4% 32.6% 

Chloroform 0.09 0.05 0.06 44.8% 23.0% 32.1% 

Methylene Chloride 0.28 0.19 0.22 40.3% 27.0% 32.7% 

Perchloroethylene 0.11 0.06 0.05 49.1% 26.9% 23.9% 

Toluene 1.69 0.97 1.57 39.9% 23.0% 37.2% 

Trichloroethene 0.01 0.01 0.01 50.1% 20.6% 29.3% 

1,3-Butadiene 

RICHLAND 

SCHOOL 

0.19 0.06 0.14 48.0% 16.1% 36.0% 

Benzene 0.80 0.43 0.65 42.8% 22.7% 34.5% 

Carbon Tetrachloride 0.09 0.09 0.09 33.7% 33.4% 32.9% 

Chloroform 0.10 0.04 0.06 49.3% 20.1% 30.6% 

Methylene Chloride 0.36 0.23 0.24 43.1% 27.7% 29.2% 

Perchloroethylene 0.22 0.10 0.07 56.6% 25.0% 18.4% 

Toluene 2.46 1.17 1.84 45.0% 21.4% 33.6% 

Trichloroethene 0.02 0.01 0.01 56.9% 19.4% 23.6% 

87 
88 

Table A11 Average and median formaldehyde and acetaldehyde concentrations (ppb) at 

the Van Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid samples (Valid N) have also been reported for each 

species along with the corresponding values from a companion monitoring station in 

Burbank (in red). 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard Burbank 

Formaldehyde (ppb) - Phase 1 

Average 3.30 2.85 3.70 N/A 4.04 

Median 3.40 2.96 3.72 N/A 4.52 

SD 1.12 1.46 1.67 N/A 1.67 

Min 1.19 0.77 1.15 N/A 0.54 

Max 5.23 5.23 6.89 N/A 6.87 

Valid N 27 26 27 N/A 28 

Formaldehyde (ppb) - Phase 2 

Average 6.05 3.66 6.52 5.64 4.80 

Median 6.18 3.23 6.77 5.98 4.76 

SD 2.10 1.60 2.22 1.68 1.72 

Min 2.54 2.24 2.87 2.54 2.44 

Max 10.2 5.95 10.3 7.56 8.41 

Valid N 22 4 22 15 19 

Acetaldehyde (ppb) - Phase 1

Average 2.55 1.96 2.31 N/A 2.17 

Median 2.37 1.96 2.39 N/A 2.48 

SD 1.07 1.05 1.22 N/A 0.97 

Min 0.97 0.53 0.72 N/A 0.31 

Max 4.56 3.80 4.53 N/A 3.81 

Valid N 27 26 27 N/A 28 

Acetaldehyde (ppb) - Phase 2

Average 3.72 2.05 3.25 3.04 1.88 

Median 3.57 1.65 3.58 3.24 2.14 

SD 1.22 1.23 1.23 0.89 0.80 

Min 1.75 1.06 1.11 1.26 0.79 

Max 5.49 3.85 5.36 4.22 3.43 

Valid N 22 4 22 15 19 
89 

Table A12 Average and median acetone and methyl ethyl ketone (MEK) concentrations 

(ppb) at the Van Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 

2 (July - September, 2006). Minimum (Min) and maximum (Max) values, standard 

deviations (SD), and the total number of valid samples (Valid N) have also been reported 

for each species along with the corresponding values from a companion monitoring 

station in Burbank (in red). 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard Burbank 

Acetone (ppb) - Phase 1 

Average 5.28 4.47 6.66 N/A 3.15 

Median 4.81 4.35 5.43 N/A 2.00 

SD 2.72 2.96 4.91 N/A 2.71 

Min 1.03 0.66 0.93 N/A 0.35 

Max 10.6 11.1 17.7 N/A 11.22 

Valid N 27 26 27 N/A 28 

Acetone (ppb) - Phase 2 

Average 4.42 2.56 5.09 5.51 0.66 

Median 4.06 1.81 4.81 5.42 0.60 

SD 2.57 1.89 3.69 2.38 0.49 

Min 1.19 1.28 1.10 2.00 0.20 

Max 12.7 5.3 18.5 11.4 2.49 

Valid N 22 4 22 15 19 

MEK (ppb) - Phase 1

Average 0.67 0.43 0.58 N/A 0.41 

Median 0.61 0.46 0.59 N/A 0.37 

SD 0.31 0.26 0.39 N/A 0.26 

Min 0.23 0.10 0.13 N/A 0.05 

Max 1.40 0.94 1.51 N/A 1.05 

Valid N 27 26 27 N/A 28 

MEK (ppb) - Phase 2

Average 0.90 0.55 0.82 0.85 0.21 

Median 0.97 0.48 0.76 0.93 0.16 

SD 0.41 0.32 0.44 0.36 0.17 

Min 0.21 0.27 0.20 0.15 0.02 

Max 1.87 0.98 1.93 1.53 0.83 

Valid N 22 4 22 15 19 
90 

Table A13 Average and median formaldehyde and acetaldehyde concentrations (ppb) at 

the Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 (October 2006 

- February 2007). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid samples (Valid N) have also been reported for each 

species along with the corresponding values from a companion monitoring station in 

Central Los Angeles (in red). Concentrations reported as 0.00 ppb represent non detected 

(ND) values. 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

Central Los 

Angeles 

Formaldehyde (ppb) - Phase 1

Average 3.16 1.91 3.14 0.00 3.32 3.14 

Median 3.14 1.92 3.11 0.00 3.32 2.84 

SD 0.59 0.40 0.44 0.00 0.71 1.61 

Min 2.13 1.19 2.28 0.00 2.12 0.97 

Max 4.41 2.74 4.26 0.00 4.92 7.41 

Valid N 37 32 25 4 34 34 

Formaldehyde (ppb) - Phase 2

Average 4.20 6.18 3.89 3.93 3.75 5.50 

Median 4.22 6.61 3.72 3.46 3.77 5.45 

SD 1.67 2.59 2.21 1.72 1.06 2.38 

Min 1.25 2.08 1.66 1.56 1.84 1.17 

Max 8.30 11.4 16.4 8.50 6.08 9.91 

Valid N 44 12 42 29 41 44 

Acetaldehyde (ppb) - Phase 1

Average 1.53 1.31 1.36 0.00 1.39 1.18 

Median 1.51 1.29 1.39 0.00 1.38 1.10 

SD 0.50 0.32 0.30 0.00 0.43 0.62 

Min 0.77 0.78 0.84 0.00 0.71 0.36 

Max 2.65 1.97 1.97 0.00 2.31 2.76 

Valid N 37 32 25 5 34 34 

Acetaldehyde (ppb) - Phase 2

Average 2.17 2.18 2.17 1.82 2.03 2.37 

Median 2.13 2.25 2.11 1.62 2.01 2.35 

SD 0.92 0.76 1.19 0.89 0.81 1.15 

Min 0.80 0.81 0.91 0.74 0.75 0.38 

Max 4.11 3.81 8.16 4.23 3.89 4.90 

Valid N 44 12 42 29 41 44 
91 

Table A14 Average and median acetone and methyl ethyl ketone (MEK) concentrations 

(ppb) at the Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 

(October 2006 - February 2007). Minimum (Min) and maximum (Max) values, standard 

deviations (SD), and the total number of valid samples (Valid N) have also been reported 

for each species along with the corresponding values from a companion monitoring 

station in Central Los Angeles (in red). Concentrations reported as 0.00 ppb represent 

non detected (ND) values. 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

Central Los 

Angeles 

Acetone (ppb) - Phase 1

Average 1.95 1.97 2.04 0.00 1.90 0.88 

Median 1.94 1.90 1.97 0.00 1.78 0.79 

SD 0.55 0.46 0.57 0.00 0.52 0.53 

Min 0.77 0.97 1.20 0.00 1.09 0.25 

Max 3.63 3.42 3.56 0.00 3.55 2.50 

Valid N 37 32 25 3 34 34 

Acetone (ppb) - Phase 2

Average 4.68 4.45 5.07 4.09 4.14 3.89 

Median 4.15 4.21 4.65 3.67 4.00 3.30 

SD 2.35 1.35 2.48 2.24 2.00 2.84 

Min 1.23 1.99 1.39 1.30 1.08 0.12 

Max 11.7 7.00 11.3 10.6 9.51 10.72 

Valid N 44 12 42 29 41 44 

MEK (ppb) - Phase 1

Average 0.30 0.29 0.29 0.00 0.26 0.15 

Median 0.27 0.29 0.28 0.00 0.23 0.13 

SD 0.13 0.10 0.07 0.00 0.11 0.09 

Min 0.12 0.15 0.20 0.00 0.12 0.05 

Max 0.57 0.49 0.41 0.00 0.60 0.38 

Valid N 37 32 25 5 34 34 

MEK (ppb) - Phase 2

Average 0.61 0.52 0.52 0.50 0.50 0.47 

Median 0.56 0.53 0.46 0.39 0.51 0.46 

SD 0.26 0.17 0.29 0.27 0.23 0.27 

Min 0.20 0.16 0.18 0.18 0.17 0.07 

Max 1.26 0.75 1.87 1.30 1.18 1.21 

Valid N 44 12 42 29 41 44 
Table A15 Average and median carbon monoxide (CO) concentrations (ppm) at the Van 

Nuys Airport during Phase 1 (November 2005 - March 2006) and Phase 2 (July - 

September, 2006). Minimum (Min) and maximum (Max) values, standard deviations 

(SD), and the total number of valid data (Valid N) have also been reported. 

Concentrations reported as 0.0 ppm represent non detected (ND) values. 

Van Nuys Airport

Golf 

Course 

Holmes 

School VOR National Guard 

CO (ppm) - Phase 1 

Average 2.3 0.6 1.1 N/A 

Median 0.7 0.2 0.7 N/A 

SD 7.7 1.0 1.1 N/A 

Min 0.0 0.0 0.0 N/A 

Max 13.6 11.8 4.0 N/A 

Valid N 1530 1973 2099 N/A 

CO (ppm) - Phase 2 

Average 0.4 0.1 0.5 0.3 

Median 0.3 0.1 0.3 0.2 

SD 0.4 0.2 0.5 0.4 

Min 0.0 0.0 0.0 0.0 

Max 2.3 1.6 2.7 3.6 

Valid N 1328 377 1331 1044 

92 
93 

Table A16 Average and median carbon monoxide (CO) concentrations (ppm) at the 

Santa Monica Airport during Phase 1 (April - July, 2006) and Phase 2 (October 2006 - 

February 2007). Minimum (Min) and maximum (Max) values, standard deviations (SD), 

and the total number of valid data (Valid N) have also been reported. Concentrations 

reported as 0.0 ppm represent non detected (ND) values. 

Santa Monica Municipal Airport

Richland 

School 

Marine 

Park 

Ernst 

Residence 

East 

Tarmac 

West 

Tarmac

CO (ppm) - Phase 1

Average 0.1 0.1 0.3 N/A 0.1 

Median 0.0 0.0 0.3 N/A 0.1 

SD 0.3 0.2 0.2 N/A 0.2 

Min 0.0 0.0 0.0 N/A 0.0 

Max 7.2 2.2 2.4 N/A 3.1 

Valid N 2804 1734 1848 N/A 2671 

CO (ppm) - Phase 2

Average 0.6 N/A 0.5 N/A 0.4 

Median 0.3 N/A 0.2 N/A 0.2 

SD 0.7 N/A 0.7 N/A 0.5 

Min 0.0 N/A 0.0 N/A 0.0 

Max 4.2 N/A 3.7 N/A 3.1 

Valid N 3061 N/A 1805 N/A 1317