Indoor air can be up to 50 times as polluted as outdoor air. In addition to particulate matter, gaseous pollutants can exist at high concentrations indoors. Gaseous pollutants, such as ground-level ozone, are also known to have health effects, including dizziness, nausea, and shortness of breath.
Indoor air pollution in office buildings comes from multiple sources, which may include:
Outdoor sources. Outdoor sources of air pollution usually enter the building through HVAC systems with inadequate air filters, doors, windows, and on people’s clothes. In poorly ventilated buildings, this pollution becomes trapped once it has entered, leading to a build-up of high concentrations of pollution indoors over time. Buildings close to high-traffic roads or in dense urban areas are particularly vulnerable to poor indoor air quality as a result of outdoor sources, such as car exhaust fumes.
Cleaning chemicals and air fresheners. Cleaning chemicals that are allowed to accumulate in the air due to poor ventilation can be a major contributor to poor indoor air quality. Similarly, air fresheners can linger in the air and worsen indoor air quality. This issue is of particular salience due to the increased frequency and intensity of cleaning and sanitation procedures in offices to combat the spread of COVID-19.
Furniture and furnishings. Cheap, mass-manufactured furniture is a common source of VOC (volatile organic compound) off-gassing. Volatile organic compounds such as formaldehyde can cause adverse health effects. Printers, copier machines, and other office equipment that use large quantities of ink also emit VOCs.
Building inhabitants. Additionally, a commonly overlooked source of indoor air pollution is the building’s inhabitants themselves, who can bring in pollen, pet dander, dust, and other particulate matter on their clothing. Human skin cells are also a large contributor to the buildup of dust, with the average person dropping approximately 40,000 skin cells every single minute. Respiration also adds moisture to the air, and respiratory droplets can carry dangerous pathogens, including the SARS-CoV-2 virus.