Page 446 - Air pollution and greenhouse gases from basic concepts to engineering applications for air emission control

Chapter 14
Indoor Air Quality

The greatest impact of air pollution on our daily life is not outdoor, but rather
indoor because we spend most of our time in indoor environments or built envi-
ronments. Air pollutants at the ground level atmosphere enter indoor environments
through windows, doors, cracks, and mechanical systems.
Indoor air quality (IAQ) engineering becomes more and more important to
modern society. And it is another relatively new topic related to air emissions and it
cannot be missed in a book like this for completeness. This chapter starts with a
brief introduction of indoor air quality (IAQ) and the sources and effects of indoor
air pollution leading to the engineering approaches to the reduction of indoor air
pollution. The approaches include source control, exhaust by hood, dilution by
fresh air (ventilation and/or in-duct air cleaning), and indoor air cleaning by air
recirculation.

14.1 Introduction

Indoor air quality (IAQ) is the quality of air in an indoor environment. The IAQ
indicators include air temperature, air relative humidity, and concentrations of air
pollutants. Temperature and relative humidity aim at primarily thermal comfort and
the others mainly health.
Indoor air quality is important for various reasons. The first and most obvious
one is that the majority of the people in a modern society spend most of their time in
indoor environments. On average, people in the industrialized countries like USA
spend 90 % or more of their lifetime indoors. Certain group of people, such as
young children and seniors, may spend more time indoors than the regular working
force. While the number may be lower in less developed nations, it could also be
even higher in cold areas like Canada and Russia.
A few decades ago, however, few people realized that there are air pollutants in
indoor environment, and that they have great negative impact on the health and
performance of the occupants. Since the early 1970s, there has been a constant

© Springer Science+Business Media Singapore 2014 427
Z. Tan, Air Pollution and Greenhouse Gases, Green Energy and Technology,
DOI 10.1007/978-981-287-212-8_14