Which of the following would be an area of concern for air quality in a shelter?

The concern regarding air quality in a shelter primarily focuses on the presence of potential pollutants and harmful substances. The absence of no-smoking signs throughout the shelter can lead to an increase in secondhand smoke exposure, which is detrimental to air quality. Without these signs, individuals may not be aware of the smoke-free policy, allowing smoking indoors, which can introduce harmful particles and gases into the air. This can trigger respiratory issues among vulnerable populations, including children, the elderly, and individuals with preexisting health conditions.

In contrast, the other options such as air purifiers, no-smoking signs, and regular ventilation contribute positively to maintaining good air quality. Air purifiers help to remove pollutants, no-smoking signs promote a smoke-free environment, and regular ventilation helps ensure that fresh air circulates, reducing the concentration of airborne harmful substances.