Which statement best describes the comparison between indoor and outdoor air quality?

The statement that indoor air quality is often much worse than outdoor air quality captures a key aspect of environmental health. Indoor environments can accumulate pollutants from various sources, such as building materials, furniture, cleaning products, and activities like cooking or smoking. These pollutants can lead to higher concentrations of harmful substances, including volatile organic compounds (VOCs), dust, and allergens, which can deteriorate indoor air quality significantly.

Outdoor air quality varies depending on factors like location, weather, and human activity. While urban areas can experience poor outdoor air quality due to vehicle emissions and industrial pollution, rural areas typically have better outdoor air quality. However, the controlled environment of indoor spaces often traps pollutants without efficient ventilation, occasionally leading to indoor air becoming more hazardous than outdoor air, particularly in tightly sealed, poorly ventilated buildings.

This understanding is crucial because it highlights the need for proper ventilation and air purification in indoor environments to mitigate health risks associated with poor indoor air quality.