Indoor Air sciences CSMI Practice Exam

What is the most common source of indoor bacteria?

1. cooling towers

2. bathrooms

3. people

4. water reservoirs

The correct answer is: people

The most common source of indoor bacteria is people. Humans naturally carry a variety of bacteria on their skin and within their bodies, which can be released into the indoor environment through simple activities such as breathing, speaking, and skin shedding. This results in the presence of bacteria in the air and on surfaces within buildings. The human microbiome is diverse, and as individuals move through shared spaces, they contribute significantly to the microbial community found indoors. While other options may also contribute to the presence of bacteria indoors, they are not as prevalent or widespread as human sources. For example, cooling towers, bathrooms, and water reservoirs can harbor bacteria under certain conditions, but they are typically not as consistent or ubiquitous as the bacterial contributions from people. Ultimately, understanding that people are the primary vectors for indoor bacteria highlights the importance of considering human activities and behaviors when assessing indoor air quality and health risks.