Risk to Ozone and ozone-derived 

oxidation products on commercial aircraft

Clifford P. Weisela

Charles J. Weschlera,b

Kris Mohana

Jack Spenglerc

Jose Vallarinoc

William W Nazaroffc

aEnvironmental & Occupational Health Sciences Institute, Rutgers University, NJ

b

International Centre for Indoor Environment and Energy,Tech Inst Denmark

cHarvard School of Public Health, Boston, MA

dDepartment of Civil and Environmental Engineering, UC, Berkeley, CA 
Background

• At cruise altitude (10000 to 11000 m), ozone levels 

outside an aircraft are high – typically 200 to 800 ppb

• Atmospheric conditions, such as folds in the 

tropopause, can result in an influx of stratospheric air 

into the lower atmosphere.

 Thus even lower flying 

aircraft can encounter 

high ozone levels
Background

• In the 1960s high ozone levels Dr. David Bates placed 

rubber bands (specially produced without antioxidants) in 

planes and observed that they cracked in an analogous 

fashion to a similar set exposed to ozone on the ground. At 

the same time toxicological symptom associated with 

ozone was observed occurring in flight attendants

• To reduce ozone on planes that cruise at high altitude 

most wide-body aircraft have ozone filters to remove ~85% 

of the ozone from the ventilation air

• However, only ~ 1/2 narrow-body aircraft remove ozone 

from the ventilation air
Background

• In 1980 FAA set an ozone standard in the airplane cabin of 

100ppb average for flights exceeded 3 hours and 250ppb 

maximum – sea level equivalent. (Note ground level 

standard in 75ppb for 8 hours and 120ppm for 1hour)

• Ozone controlled by converters and route planning – but 

not all planes with converters

• Ground levels standards lowered several times since 1980

• Ground level ozone is also considers other photochemical 

oxidants and indoor air studies have found that ozone 

reacts to form additional compounds

• Simulated aircraft cabin studies have identified the 

formation of aldehydes by ozone
Ozone levels on transcontinental aircraft

C2 In-Flight Ozone Concentration 

Westbound Trans-Continental

Q1 2009

B 757 - 200

No ozone converter

0

20

40

60

80

100

120

0 1 2 3 4 5 

Hours after take-off Ozone concentration (ppb)

Sampling duration: 5.0 h

Max 1-minute ozone (ppb): 103

Max 1-hour ozone (ppb): 84

Sample avg. concentration (ppb): 54 Eastbound Westbound

•At cruise altitude, 

ozone outside aircraft 

~ 200 - 800 ppb

•Only about half the 

narrow-body aircraft 

remove ozone from 

ventilation air

•Ozone levels in 

commercial aircraft 

cabins are frequently 

> 50 ppb

120

100

80

60

40

20

0
In-flight ozone data - transcontinental

Transatlantic Flight Ozone Concentrations

B 747 - January 2009

With ozone converter

0

20

40

60

80

100

120

0 1 2 3 4 5 6

Hours after take-off Ozone concentration (ppb)

Westbound

Eastbound

Planes (747) had ozone converter. The condition were not 

known and the have a limited lifetime of effectiveness.
Measured O3

levels (52 flights)

Weisel, CP, Weschler, CJ, Mohan, K, Vallarino, J, Spengler, JD “Ozone and Ozone By-Products in the 

Cabins of Commercial Aircraft” Environmental Science and Technology, 47 (9), 4711–4717, 2013

Box plot:

Line – median

Box – 25th & 75th
O3 & humans in a simulated aircraft cabin

• 16 passengers; 4-hour flights

• Outdoor airflow: 4.4 h-1 or 8.8 h-1 ; total airflow: 23 h-1

• [O3]: 60 to 80 ppb Chiller

Cabin

Chamber

Outdoor Air

Filter

Exhaust

Exhaust

Dehumidifier +

System for external 

chamber

Pollution

Chamber

HEPA

filter

Weschler et al., Environ Sci &Technol 41, 6177 (2007)

Simulated B-767; 3 rows, economy
Chemical measurements

• Proton Transfer Reaction/Mass Spectrometry 

(PTR/MS) (Identify transient and unknown 

compounds)

• Multi-Sorbent tubes (Volatile Organic Compounds)

• DNPH cartridges (Formaldehyde & Acetaldehyde)

• DNSH cartridges (Acrolein)

• UV (Ozone)

• Nondispersive Infrared (Carbon Dioxide)
In-plane sources of O3

-reactive chemicals

Occupants Skin oil (i.e., squalene, oleic acid, 

unsaturated sterols), isoprene, 

nitric oxide (NO), 

Carpet & backing 4-PCH, 4-VCH, unsaturated fatty 

acids

Seats Skin oil, fabric

Soiled air filters Unsaturated organics associated 

with captured particles
Humans are large O3

sinks

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

10:00 10:30 11:00 11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:30 16:00 16:30 17:00 17:30 18:00

Time, h

O3 concentration, ppb

Pollution Chamber Cabin background

people inside the cabin 7 O3 generators turned on 7 O3 generators turned off 7 O3 generators turned on 7 O3 generators turned off 

~ 50 ppb

airflow: 75 L/s (8.8 h-1)

Simulated aircraft cabin

Weschler et al., Environ Sci &Technol 41, 6177 (2007)
Ozone reactive constituents of skin oil

• Squalene (~ 10 – 15 μg/cm2)

• Unsaturated fatty acids: (~ 11 – 17 μg/cm2)

– Some with Δ

6 unsaturation unique to humans

• Cholesterol (~ 3 – 4 μg/cm2)

• Vitamin E (~ 0.013 – 0.020 μg/cm2)

• Ubiquinone, aka CoQ10 (~ 0.012 – 0.018 

μg/cm2)

• Even smaller amounts: vitamin A, β-carotene, 

lycopene, ascorbic acid, glutathione, uric acid

O3
Saturated aldehydes produced by ozone 

and are irritatants

Weschler et al., ES&T 2007

0

5

10

15

20

25

30

no ozone, 4.4/h

ozone, 4.4/h

no ozone, 8.8/h

ozone, 8.8/h

average level (ppb) .

formaldehyde acetaldehyde sum C4-C8 nonanal decanal
Organic acids produced by ozone with one 

an irritatant

Weschler et al., ES&T 2007

0

5

10

15

20

no ozone, 4.4/h

ozone, 4.4/h

no ozone, 8.8/h

ozone, 8.8/h

average level (ppb) .

formic acid acetic acid
Acetone, 6-MHO and 4-OPA

Weschler et al., ES&T 2007 0

10

20

30

40

50

60

no ozone, 4.4/h

ozone, 4.4/h

no ozone, 8.8/h

ozone, 8.8/h

average level (ppb) . acetone (PTR/MS) 6-methyl-5-hepten-2-one 4-oxopentanal
Humans are large O3

sinks

25%

7%

10%

56%

2%

Seats HEPA Filter

Other Surfaces People

Respiration

Contribution 

of different 

sinks to 

ozone 

removal in 

simulated 

Boeing 767
Symptom evaluations – DTU Chamber Study

Stom-Tejsen, Weschler, Wargocki, Myssklo, Zarzycka The influence of ozone on self-evaluation of 

symptoms in a simulated aircraft cabin., JESEE, 18, 272-281, 2008 

Ozone in Cabin 

(ppb)

Flow of outdoor air 

(l/s/person)

Outdoor AER (h-1) Flow of outdoor air 

(kg/m/person)

<2 2.4 4.4 0.17

61 2.4 4.4 0.17

<2 4.7 8.8 0.34

74 4.7 8.8 0.34

29 Female Subjects, 19-27 years

4 hour simulated flights 3row-21seat section

Completed questionnaires are various times during simulation

Statistical evaluation p<0.05 for significance
Symptom evaluations – DTU Chamber Study

Stom-Tejsen, Weschler, Wargocki, Myssklo, 

Zarzycka The influence of ozone on selfevaluation of symptoms in a simulated 

aircraft cabin., JESEE, 18, 272-281, 2008 
Air Quality and Symptoms Evaluated
Results – box plot of selected outcomes
Results

• Based on self-reported symptoms at 3.75 hr point:

• Air quality & 12 symptoms (eye/nasal irritation, 

lip/skin dryness, headache, dizziness, tension, 

chlaustrophbia) were significantly worse for “ozone” 

condition compared to “no ozone” condition

Stom-Tejsen, Weschler, Wargocki, Myssklo, 

Zarzycka The influence of ozone on selfevaluation of symptoms in a simulated 

aircraft cabin., JESEE, 18, 272-281, 2008 
In-flight evaluation of ozone by-products 

Approach

• Sampling package – 2BTech Model 205 Dual 

Beam Ozone Monitor battery operated

• BGI Pump with Mixed bed adsorbent trap for C6-

C10 aldehydes with KI trap (to remove ozone) 

and DNPH-Cartridge for Formaldehyde

• Sampling equipment place under seat with 

Teflon tubing inlet and sampling traps in 

breathing zone 
Sample analysis

• Ozone monitor is a real time instrument based 

on UV absorption with 1ppb sensitivity and 1 

minute averaging time

• Adsorbent traps analyzed by thermal desorption 

coupled to GC/MS

• DNPH extracted with actonitrile and analyzed by 

HPLC/UV
O3 & humans in real aircraft cabins

• Ozone and carbonyls 

measured on 52 flights

• Mostly transcontinental U.S. 

flights; some transoceanic 

flights 

• B-737, B-747, B-757 & B-777

• Ozone scrubber upstream of 

sorbent tube to avoid ozone 

reacting w. 6-MHO on sorbent

Weisel, CP, Weschler, CJ, Mohan, K, Vallarino, J, Spengler, JD “Ozone and Ozone By-Products in 

the Cabins of Commercial Aircraft” Environmental Science and Technology, 47 (9), 4711–4717, 2013
O3 & humans in real aircraft cabins

• Statistically significant correlations between:

• O3and 6-MHO

• 6-MHO and % occupancy

Weisel et al, Environ Sci &Technol 2013 

Compound Median (ppb) Maximum (ppb)

Hexanal 2.8 8.4

Heptanal 0.77 4.0

6-MHO 0.73 13

Octanal 0.75 4.5

Nonanal 1.9 14

Decanal 1.6 12
Other in-plane sources of O3

-reactive chemicals

Carpet & backing 4-PCH, 4-VCH, 

oleic acid, other 

unsaturated fatty 

acids

Seats Skin oil, fabric

Soiled air filters Unsaturated 

organics 

associated with 

captured 

particles
Summary

• Ozone is present on transcontinental US flight and when ozone 

converter not working optimally

• When O3 present, concentrations of aldehydes, ketones & 

organic acids much larger

• People are major O3 sinks – larger than carpet, seats and dirty 

HEPA filter combined

• Humans + O3 →acetone, nonanal, decanal, 6-MHO, geranyl 

acetone, 4-OPA 

• Presence of O3 and O3-derived products adversely affected 12 

of 29 self-reported symptoms
Broader implications

• Ozone is present at levels exceeding 100ppb on aircraft without 

ozone convertors and if the converter is not functioning 

correctly, though not routinely exceeding current FARS

• EPA Ground Level Standards 75ppm over 8 hours, though 

USEPA-SAB recommended lower level

• Chemistry producing ozone by-products occurs whenever O3

and humans simultaneously present in a room or aircraft

• Potential effects of by-products across current flying public still 

to be determined - O3 can be filtered from ventilation air
Quantifying Exposure to 

Pesticides on Commercial Aircraft

Clifford Weisel

Environmental and Occupation Health Sciences Institute

Rutgers University

Sastry Isukapalli

Panos Georgopoulos

Binnian Wei

Kris Mohan

Sagnik Mazumdar

Yong Zhang
Congressional Mandate

• MANDATE: Collect pesticide exposure 

data to determine exposures of 

passengers and crew

• Approach:

– Measure surface loadings on commercial aircraft

– Measure urinary pesticide biomarker levels in 

flight attendants

– Apply CFD model to Top of Descent Spray and 

evaluate model with measurements

– Estimate the risk to flight crew from pesticides
Research Objectives

• Wipe Samples

– Evaluate what aircraft surfaces and flights routes 

have pesticides 

• Biomarker of Pesticides in Flight Crew

– Determine urinary pyrethroid metabolites for flight 

attendants

– Evaluate permethrin PBPK model for flight attendants

• CFD Model from Top of Decent Disinsection

– Computational Fluid Dynamic (CFD) modeling to 

predict air concentration and surface loading 

– Evaluate with data from KSU’s mock 757 aircraft

• Risk Paradigm to Permethrin

– Estimate risk based on exposures
Purpose of Aircraft Disinsection

To prevent or minimize the transport of insects 

which pose a health threat to humans, animals 

and plants 

• Adopted by US in the 1930s; discontinued since 

1979

• Required by many other countries currently, e.g., 

Australia, New Zealand, India, China and many 

islands

• Most countries reserve their right for this practice 

on flights from particular regions of endemic 

diseases
Disinsection Methods

• When passengers and flight 

crew are on board: Top of 

descent, blocks away and, 

pre-flight. (phenothrin, 

permethrin, or both)

• During scheduled 

maintenance (no 

passengers on board): 

Residual treatment: 

(permethrin)
What Was Collected

• Examined surfaces on aircraft from

– 15 US domestic flights, 

– 18 flights landing in Central or South America, 

– 8 flights landing in Australia or New Zealand, 

– 4 flights landing in Africa or Europe and 

– 15 flights landing in Asia during 2008 and 2009 

• Collected from Seat Cushions, Seat Backs, Tray 

Tables, Arm Rests, Galley Area, Lavatory

• Problem with recovery – so only relative 

amounts are determinable
Mock Boeing–Simulated Disinsection

Surface Loading (μg/cm2)

High Ventilation Low Ventilation

50-CMa 100-CMb 50-CM 100-CM

25th percentile 0.13 0.08 0.53 0.48

median 0.13 0.11 0.69 0.64

75th percentile 0.14 0.13 0.83 0.90

max 0.19 0.16 1.07 0.98

N 10 17 15 22

% RSD 22 29 30 32

Destination 

Continent

Permethrin 

Mean * (max)

Phenothrin

Mean*(max)

Total 

Flights

Permethrin 

Above 

Detection

Phenothrin 

Above 

Detection

Asia 0.034±.002 

(0.035)

0.031±.026 

(0.061)

3 2 3
Surface Loading by Surface Type

(Relative amounts per cm2)

* * *

Hard Surfaces Soft Surfaces
Surface Loading by Origin (Country)

(Relative amounts per cm2) 
Surface Loading by Destination

(Relative amounts per cm2) 
Conclusions

• Pyrethroids were not detected on US domestic 

flights 

• Pyrethroids were routinely detected on

international flights

– To/from countries requiring disinsection, performed 

maintenance of aircraft or may use aircraft that 

service selected countries

– Permethrin detected for residual 

– Permethrin & phenothrin in on board spraying

• Use of KSU’s mock Boeing 767 aircraft cabin 

documented inhalation and dermal exposure 

during simulated disinection with passengers
Biomarker of Pesticides in 

Flight Crew

Urinary Metabolite Levels of 

Pyrethroid Insecticides in 

Flight Crew

References: Wei, B, Mohan, K, Weisel, CP “Exposure of Flight 

Attendants to Pyrethroid Insecticides on Commercial Flights: Urinary 

Metabolite Levels and Implications, Occupational and Environmental 

Medicine, 215(4) 465-473, 2012 and Wei, B, Isukapalli, SS, Weisel, CP 

“Physiologically Based Pharmacokinetic Modeling of Exposure 

Pyrethroids Insecticides in Flight Attendants”, Journal of Exposure 

Science and Environmental Epidemiology, 6 March 2013; doi: 

10.1038/jes.2013.12, 
Project Objectives

Do we see elevated levels of urinary 

pyrethroid metabolites in flight crew 

after they fly on aircraft that were 

disinsected?

How do those levels compare with other 

populations?

Can they be used to drive 

pharmacokinetic models and in 

population risk estimates?
Urinary metabolites of pyrethroids

Pyrethroid metabolites measured:

 3-phenoxybenzoic acid (3-PBA), 

 cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane 

carboxylic acid (cis-, and trans-DCCA), 

 cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic 

acid (cis-DBCA)

 4-fluoro-3-phenoxybenzoic acid (4F-3-PBA) 

Wei et al 2011
Urinary metabolite levels of 3-PBA

creatinine corrected
Urinary metabolite 3-PBA

Sorted by Domestic & International Flights

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

Domestic USA to

other N.

America

USA to

Europe 

USA to

Asia 

USA to

Australia

Australia to

USA

Europe to

Asia 

Europe to

USA 

Urinary concentration of 3-PBA (ug/g, creatinine) 

0.0

5.0

10.0

15.0

20.0

25.0

Domestic USA to other

N. America

USA to Europe USA to Asia USA to

Australia

Australia to

USA

Europe to Asia Europe to USA 
Urinary metabolite levels with time since 

disinsection
Comparison with Other Studies

Type Conc. of 3-PBA (ug/L) Reference

US general population

0.324 (GM)

0.29 (50th) – 3.35 (95th)

Barr et al., (2010)

Greenhouse workers 2-52 Tuomainen et al., 1996

Pest control workers 0.5- 277 Leng et al., 1997

Forestry worker 260 Kolmodln-Hedman et 

al.,1982

Flight attendants

0.8 – 81.5 (min - max)

5.2 – 51.0 (50th – 95th)

This study

Exposure of flight attendant to permethrin 

is similar to those pesticide applicators
Rationale for Model and Approach

•PBPK models provide estimate of target 

tissue dose associated with an exposure

•Provide input for risk paradigm

•Develop and validate PBPK model for 

permethrin

•Assess potential variability in model 

•Evaluate it with animal & human data

•Simulate exposure to flight attendants
Model Structure

Alveolar

Fat

Rapidly perfused

Slowly perfused

Skin

Excretion 

compartment

Inhalation exposure Exhalation

Brain

Intestinal Stomach Oral 

exposure

QB

QSK

QF

QR

QS

KSI

KI KS

Fecal excretion

Kfec

Urinary excretion

Kmetl

Liver QL

Kur

Blood 

clearance 

Dermal 

exposure

Blood compartment
Comparison to Animal Data

97.5th percentile

75.0th percentile

50.0th percentile

25.0th percentile

2.50th percentile

1.0 mg/kg oral dose 10. mg/kg oral dose 

Lines are modeled 

time-conc profiles

Yellow circle are 

experimental data 

(USEPA 2007)
Comparison to Human Data

Modeling total urinary excretion 

rate of permethrin metabolites, 

cis/trans-3-(2,2-Dichlorovinyl)-2,2-

dimethylcyclopropane carboxylic 

acid (CAV) (data from TomalikScharte et al., 2005).

215 mg 

permethrin 

applied on head 

treatment for lice

3 g permethrin 

applied as cream 

onto dried skin 

treatment for scabies

3 g permethrin 

applied as cream 

onto dried skin 

treatment for scabies
Permethrin Exposure Scenarios

Aircraft Disinsection

Residual Treatment Pre-flight Spray

Done on the ground, with no crews 

and passengers on the plane 

Surface loading

(entire flight) 

log-normal distribution

median: 35; STD: 35; 

range: 0.5 – 140; 

unit: μg/cm2

 Air concentration 

(entire flight)

log-normal distribution 

median: 0.5, STD: 0.5;

range: 0.0 – 1.0 

Unit: μg/m3

Can be done by crewmembers 

just prior to a plane’s departure

Surface loading

(entire flight) 

log-normal distribution

median: 0.58; STD: 0.58; 

range: 0 – 2.32; 

unit: μg/cm2 

Air concentration

(stage I) 

log-normal distribution 

median: 65; STD: 65; 

range: 1.0 – 260; 

unit: μg/m3 

Air concentration

(stage 2) 

log-normal distribution 

median: 0.5, STD: 0.5;

range: 0.0 – 1.0 

Unit: μg/m3
Predicted Urinary 3-PBA Conc for 

residual treatment scenario

Red box – measured levels for flight attendants
Predicted Urinary 3-PBA Conc for 

pre-flight spray scenario
Conclusions

• Simulated 3-PBA concentrations in post- and 

24-h-post urine were comparable to previously 

measured results. 

• For residual disinsection mean (90th%) 

predicted 3-PBA levels were 50 (350) μg/L with 

dermal providing ~84%, oral ~16 %, inhalation 

~1 % 

• For Pre-spray disinsection mean (90th%) 

predicted 3-PBA levels were 10 (75) μg/L with 

inhalation providing ~90%, dermal ~5 %, oral 

~3 % 
RISK ASSEMENT PARADIGM

Component 1: Determine air concentrations and 

surface loading over time

Initial conditions CFD Modeling for Spraying

or Suggested Loading for Residual

Removal with time through contact, cleaning, volatilization

Component 2: Human activity that leads to contact

Frequency and duration of flight

Breathing rate

Inadvertent ingestion

Touching Rate

Component 3: PBPK modeling to determine uptake and 

distribution in the body

Estimate of risk by comparison to literature hazard values
CFD Pesticide Modeling

•Computational Fluid Dynamic (CFD) models provide an 

effective methodology for characterizing concentration 

distributions and exposures at a high spatial and temporal 

resolution

•CFD program FLUENT was used with a Re-Normalization 

Group (RNG) k-ε turbulence model

•Current model for a twin-aisle 11 row cabin mockup of a 

Boeing 767 cabin 

•Evaluated the model with air concentration and surface 

loading measurements following simulated top of descent 

disinsection application

•Reference: Isukapalli, SS; Mazumdar, S; George, P; Wei, B; Jones, B; Weisel, C P, 

Computational fluid dynamics modeling of transport and deposition of pesticides in 

an aircraft cabin. Atmospheric Environment, 68, 198-207, 2013.
Data for model evaluation done at 

KSU Mock Boeing 767

Schematic of the Sampling Locations

 1 2 3 4 5 6 7 8 9 10 11

G

F

E

D

C

B

A

Inlets

3D 6D 9D

6G

6A

Seat-top
The CFD model and case setup for 

sideways and overhead spraying of 

pesticide in the 11-row cabin mock-up

Sideways

Overhead
Comparison of airflow across the cabin 

cross-section

1400 CFM (29 ACH)

48 CFM (1 ACH)
Breathing Zone Concentration (μg/m3

) at 

1400cfm (29ACH) and 48cfm (1ACH)

Sideways
Net Deposition (μg/cm2

) 1400cfm (29ACH) 

and 48cfm (1ACH)

29 ACH 1 ACH
Comparison of Model and Experimental 

Deposition (μg/cm2) at High Ventilation

CFD

Experiments

Lap Lap

Seat-top Seat-top

Sideway Spray Overhead Spray
Comparison of Model and Experimental 

Deposition (μg/cm2) at Low Ventilation

CFD

Experiments

Lap Lap

Seat-top Seat-top

Sideway Spray Overhead Spray
Conclusions

•CFD model was effective for studying the spatial and 

temporal variation of pesticide deposition and 

concentration 

•Contrasting flow features were observed for the high-29 

ACH and the low-1 ACH

•Surface deposition levels at measured locations varied 

from 0.33-1.22 μg/cm2to 0.05-0.20 μg/cm2for the low 

and high ventilation, respectively and the air 

concentration decline much more rapidly (8 min vs 20 

min) at high ventilation

•CFD Model results at high ventilation matched 

experiment results well, but at low ventilation differences 

near the window seat were observed
RISK PARADIGM

•Pesticide exposures to crew and passengers can occur

–Inhalation while there is active spraying (Top of Descent)

–Inhalation from volatilization or resuspension of dust 

–Dermal from direct contact with ski

–Unintentional ingestion from transfer to hands or food

•Top of descent, residual and preflight spray treatments 

were all considered

•A methodological approach was developed that can be 

used for other agents in an aircraft cabin

•Reference:Zhang, Y, Isukapalli, S, Georgopoulos, PG, Weisel, CP. “Modeling 

Flight Attendants’s Exposures to Pesticides in Disinsected Aircraft Cabins”, 

Environmental Science and Technology: 47(24):14275-14281, 2013. doi: 

10.1021/es403613h. Epub
EXPOSURE CONSIDERATIONS

•Each crew member was assigned four different time 

periods during which the exposure was calculated for. 

(Remain time = 24 hours –T1-T2-T3)
SURFACE LOADINGS AND AIR 

CONCENTRATIONS

•Input from CFD model for spraying.
Overall Summary and 

Recommendation

• Flight attendants and passengers are being 

exposed to pyrethroid pesticides on aircraft 

that were disinsected

• The urinary metabolite levels of permethrin for 

flight attendants after working on disinsected 

aircraft is similar to pesticide applicators

• The risk associated with disinsection should be 

reevaluated based on these exposure data 

exposure and new toxicological studies of the 

adverse health effects of pyrethroids
Conclusions

• Flight attendants working on the pyrethroids 

disinsected aircrafts had significantly higher levels of 

3-PBA, cis- and trans-Cl2CA in the post- and 24-hpost flight urine samples than those working on nondisinsected aircrafts and the general U.S. population

• The urinary levels of 3-PBA, cis- and trans-Cl2CA 

exponentially decay with post disinsection duration

• Permethrin exposure of flight attendants flying on 

disinsected aircrafts is similar to pesticides applicators.