**Abstract**

This chapter summarizes the work done at the Airliner Cabin Environment Research Lab (ACERL) related to air quality, airflow characteristics, and human thermal comfort inside aircraft cabins. The laboratory is part of the Institute for Environmental Research (IER) at Kansas State University. It has a Boing 767 mockup cabin, bleed air simulator, and a Boeing 737 actual aircraft section that were all utilized to conduct experimental studies to understand air quality inside aircraft cabins. The studies summarized in this chapter include particle image velocimetry (PIV) investigations, particle dispersion, computational fluid dynamics (CFD) simulations, tracer gas and smoke visualization studies, and bleed air investigations. The chapter also summarizes other related studies including virus dispersion, air quality monitoring devices, and related developed air quality standards. The scope of this chapter is to summarize the setup and results of each of the above categories. This summary along with the cited references provides results for full size aircraft cabin environments, helps validate data for CFD simulations, and provides comparison data for other similar studies. This helps improve the design of future aircraft cabins and their ventilation systems and recommends changes to maintenance practices done that can improve the health and safety of humans inside these enclosed compartments.

**Keywords:** indoor air quality, airflow simulations, human health and safety, particle dispersion, aircraft cabin environment, bleed air, tracer gas

## **1. Introduction**

Biological incidents such as severe acute respiratory syndrome (SARS) and swine flu (H1N1) transmission have been detected on flights. Ebola was the latest virus threat on board air-flights. Chemical incidents are also detected and reported inside commercial aircraft passengers' cabins. Odors and fumes from bleed air, viruses, and bacteria can result in serious health hazards for cabin crew members and passengers and have an important impact on aircraft air quality [1].

The purpose of this chapter is to summarize studies related to airflow studies, air speed and turbulence characteristics inside aircraft cabins. This can help aircraft manufacturers and operators in providing the occupants with acceptable air quality that meet safety guidelines and codes while maintaining the passengers' comfort in these enclosed and pressurized compartments.

#### *Indoor Environment and Health*

In addition to that, the studies presented in this chapter provide important information to help in validating simulations and CFD codes developed to understand airflow behavior inside aircraft cabins.
