Measurements in the sky Jørn T. Brunsell, Ph.D. Head of Department Norwegian Building Research Institute

Background Perceived concern about health and safety of passengers and crew: High levels of CO 2 and other pollutants Low relative humidity Transmission of infectious disease EU’s 5th Framework, Key Action 4 ” New perspectives in aeronautics”: Develop solutions for an improved cabin environment Improve aircraft fuel efficiency CabinAir Project

Measurements in the sky - objectives Develop an innovative methodology for monitoring cabin air quality Comprehensive investigation of indoor air quality in aircraft cabins Input to technology development activities in the CabinAir project Identify parameters appropriate to the development of standards

Results of ”Measurements in the sky” Monitoring results Cabin thermal comfort Contaminants Crew questionnaire results Changes in symptom intensity during flight Assessment of cabin environment

Measurement program 50 flights Three airlines: BA, KLM, SAS Three monitoring teams: BRE, TNO, NBI Four generic aircraft types Short narrow body Long narrow body Twin aisle Double deck

Stationary ’Mannequin’ measurements Air and globe temperature Air velocity CO 2 Relative Humidity, RH Ozone CO

Mobile measurements Air velocity Temperature VOCs Micro- biologicals Particles CO 2

Cabin comfort - temperatures Aircraft Group PlacePhase Temperatures nMeanMinMax 1EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise

Horizontal temperature differences 5 flights with horizontal temp. difference > 3°C for more than 100 minutes (between different cabin climate zones). 1 flight: Average temp. at economy class 5.5°C above zone set-point for 11.5 hours. Temperature anomalies can be quite localised

Vertical temperature differences 15 of 33 flights (45%) exhibited vertical temp. difference > 3°C for at least 30 minutes at business mannequin 13 of 43 flights (30%) exhibited vertical temp. difference > 3°C for at least 30 minutes at economy mannequin

Cabin comfort – air velocity Aircraft Group PlacePhase Air velocity nMeanMinMax 1EconomyGround Cruise40.1 BusinessGround Cruise EconomyGround40.1 Cruise BusinessGround20.1 Cruise20.1 3EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise

Air velocity Same areas on same aircraft exhibited high air velocities Worst cases: air velocity > 1 m/s for more than an hour at two seats on one aircraft type. Draught conditions can be quite localised

Cabin thermal comfort – relative humidity RH < 30% for 97% of time after take-off On all long haul flights RH dropped below 10% except for one flight (In highest passenger density area of economy class)

Cabin air quality – CO 2 Aircraft Group PlacePhase Carbon dioxide concentration nMeanMinMax 1EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise EconomyGround Cruise BusinessGround Cruise

Cabin air quality – carbon dioxide CO 2 concentration > 2000 ppm gate-to-gate and cruise: Economy class: Gate to gate: 1.5%, Cruise: 0.1% Business class: Gate to gate: 0.5%, Cruise: 0% ppm difference between highest density area of economy class and business class on some flights

Cabin air quality – air pollutants CO: Below detection limit during cruise (< 10 ppm) Ozone: Not detected above background level (< 20 ppb)

Cabin air quality – Volatile Organic Compounds (VOC) VOC concentrations comparable to other indoor environments on ground Benzene < 0.5 µg/m 3 Limonene : µg/m 3

Volatile Organic Compounds cont... Aldehydes and ketones: Formaldehyde < 5 µg/m3 Acetaldehyde: µg/m³ Acrolein < 1 µg/m³ Acetone: µg/m3

Cabin air quality - SVOC SVOC: measured only in cabin, not bleed air Naphthalene < 10 µg/m 3

Cabin air quality Ultra fine particles (0.02 to > 1 µm) Very low concentrations at cruise altitude Higher concentrations on ground Episodic high concentrations at cruise altitude, possibly linked to meal service

Cabin air quality Endotoxins: units/m 3 during boarding, not detectable during cruise Microbiologicals Bacteria: cfu/m 3 Fungi: cfu/m 3

Questionnaire study 309 questionnaire responses 46 flights Cabin crew and flight crew Changes in symptom intensity during flight and assessment of cabin environment

Cabin environment - all flights

Cabin environment - by flight length

Change in score – feeling tired Symptom change - all flights Change in score – dry skin/lips Change in score – dry nose Change in score – dry eyes

Symptom change Aircraft type Dry skin/lips Double deck Dry skin/lips Twin aisle Dry skin/lips Single aisle Feeling tired Double deck

Statistical Regression approach to analysis Investigate the dependence of symptom change on the concurrent influence of all explanatory variables measured.

Statistical Regression Common finding Symptom change was related to duration of flight and individual cabin / galley comfort assessment: –A longer flight – more change –Less comfortable – more change

Statistical Regression Increase in RH is weakly associated with smaller changes in symptoms related to dryness

Statistical Regression Results not consistent enough across the data sets analyzed to make any firm conclusions about possible associations between carbon dioxide concentrations, air velocities or temperatures and symptom changes on monitored flights.

Statistical Regression Summary The models were highly sensitive to change in the dataset analysed.

General conclusions None of the measured values of indoor air quality are at levels of concern for health and safety of passengers or crew. Some measured values of thermal parameters are outside comfort range. Symptom change is related to duration of flight and overall individual comfort assessment

Conclusions: Technology development ECS and Air distribution: Better local control of the cabin environment is desirable Filtration: Filtering of outside air may be desirable while aircraft is on ground