Which of the following is NOT a characteristic of volatile organic compounds (VOCs)?

The option stating that volatile organic compounds (VOCs) are "always harmful to human health" is not a characteristic of VOCs. While many VOCs can indeed pose health risks and contribute to various health issues, not all VOCs inherently exhibit harmful effects at all concentrations or exposure levels. The impact of VOCs on human health depends on several factors, including the specific chemical, duration of exposure, concentration, and individual sensitivities.

In contrast, VOCs are known for being emitted from a variety of products and processes, such as paints, solvents, and cleaning agents, making their release into the environment a common occurrence. They are also recognized for their role in indoor air pollution due to their ability to accumulate in confined spaces, often leading to higher concentrations indoors than outdoors. This accumulation can exacerbate health issues, particularly in poorly ventilated areas.

Overall, the nature of VOCs involves a complex interaction with human health, where many compounds can be harmful, but it is not accurate to claim that they are "always harmful." Understanding this nuanced perspective is crucial in occupational hygiene monitoring and assessing the risks associated with exposure to these compounds.