10 Public Places with the Worst Indoor Air

By now, you are probably aware of how the air quality in your home can affect the health of you and your family. You may have even taken precautions to protect the indoor air quality of your home, such as buying an air purifier or improving the filter in your HVAC system. Unfortunately, it is more difficult to avoid poor indoor air when you are out in public. Most airborne pollutants are too small to be seen with the naked eye, and many can be odorless, so how can you tell whether the air that you are breathing contains harmful toxins or volatile organic compounds (VOCs)?

According to the EPA, Americans spend about 90% of their time indoors, breathing air that can have airborne pollutant concentrations two to five times higher than that of outdoor air. Considering that poor indoor air quality can cause health effects ranging from headaches and nasal irritation to heart and respiratory diseases, many people take appropriate precautions to make sure that the air inside of their home is as clean as possible. However, if you go out in public you cannot always avoid spending time in buildings with bad indoor air quality, but you can learn the warning signs of potentially harmful air quality and take steps to limit your time in buildings with poor indoor air. We discuss 10 of the worst indoor air quality offenders open to the public (and what you can do to protect yourself) below.

1. Malls

Whether you love going to the mall or begrudgingly go there to buy last-minute gifts, the chances are that you visit a shopping mall at least a few times each year. Unfortunately, these shopping centers may have worse indoor air quality than you expect. In a mall, HVAC systems certainly have their work cut out for them, considering the building’s abundance of fragrant perfumes, cooking fumes from the food court and the carbon dioxide and humidity of exhaled air. Old or ill-maintained HVAC systems may not be up to the task, especially if the mall is prone to mold or mildew.

2. Office buildings

Office buildings are so frequently cited for poor air quality that there is even a term used to describe illness caused by the lack of clean indoor air in the workplace—Sick Building Syndrome (SBS). When you consider the air quality factors present in an enclosed office space, including the offgassing of office furniture and electronics, stale air, sick co-workers and any manufacturing or other high-polluting businesses that may share the building, you may want to think twice about the air quality in your workplace. Dust, mold, humidity, inadequate ventilation and smoking near building doors can also affect your office’s indoor air quality, according to the EPA.

3. School classrooms

Air quality in schools is especially important because it can affect a child’s physical health and development as well as their ability to learn. For example, higher levels of carbon dioxide in schools have been linked to higher rates of student absences (Shendell, et. al, 2004). Many schools are housed in decades-old buildings that are in need of repairs and may not have HVAC systems equipped to handle the high volume of people and pollutants present in the school each day. Airborne pollutants can come from many different sources, including school bus and other vehicle exhaust near building doors, cleaning chemicals, classroom pets and mildew.

4. Doctor’s offices

When you go to the doctor’s office for a routine visit, the last thing you want is to leave with an infection. Even in a waiting room that has separate sections for those that are sick and those that are healthy, there is not usually much to restrict airborne pathogens from flowing between the two areas. Additionally, the air quality in doctor’s offices can be affected by the offgassing of medical machinery and office equipment (Mahmoud & Mohamed, 2014).

5. Apartment buildings

Maintaining your indoor air quality in an apartment comes with some unique challenges. For example, apartment units typically have few windows, due to shared walls, decreasing the transfer of indoor and outdoor air. A shared ventilation system also means the potential for airborne pollutants, such as paint fumes or secondhand smoke (including vape smoke from e-cigarettes), to enter your apartment from others in your building. Laundry rooms, shared hallways and trash areas are also at risk for sub-par ventilation and high-concentrations of airborne pollutants. As a tenant, you can improve the cleanliness of your indoor air by removing pollutant sources, increasing ventilation and adding an air purifier to your space. For bigger problems, such as a neighbor’s secondhand smoke seeping into your unit, you may need to turn to the building manager for a solution.

6. Restaurants

When you go out to eat, germs, toxins and other airborne pollutants might be the furthest thing from your mind, but unfortunately, the air quality in restaurants is not always up to the same standards as the food. Restaurants need HVAC and exhaust systems that can handle the smoke from open flames, heated cookware and always-on ovens and grills. When a restaurant has inadequate ventilation, fumes from the kitchen can easily make their way into the dining area. Additionally, in restaurants that allow smoking, cigarette smoke may be present in all areas of the restaurant, even if it the restaurant has a designated smoking section (Milz, et. al, 2007).

7. Bars

Bars are one of the worst public places when it comes to cigarette smoke. No matter the ventilation quality of the bar, gases and particulate matter from cigarette smoke pose a major indoor air quality concern. As the tobacco smoke settles, the chemicals and odors present in the smoke become trapped in the furniture, pool tables and carpeting of the bar, exposing you to pollutants from cigarettes even if no one is currently smoking. The California Department of Public Health calls this tobacco residue “thirdhand smoke.”

8. Casinos

Like bars, casinos are notorious for their high levels of secondhand smoke. However, unlike bars, casinos are built with the aim of keeping people inside for as long as possible. Large, enclosed buildings with few windows and doors combined with many people sitting in close quarters (and smoking) can lead to an indoor air quality nightmare. Even in casino restaurants that do not allow smoking, the proximity to smoking-allowed gaming areas means that the restaurants still have indoor air pollution levels exceeding the EPA’s indoor air quality standards (York & Lee, 2010).

9. Train and bus stations

Many commuters take buses and trains, and most stations have a lobby where you wait before departing. Air quality concerns inside these waiting areas stem from diesel emissions, which can contain oxides of nitrogen, black carbon (soot), carbon dioxide, carbon monoxide and other harmful pollutants (Hickman, et. al 2018). When you think about the extent of pollutants produced around a railway platform, it is not difficult to understand how these pollutants could accumulate to harmful levels.

10. The subway

Like train stations, subway platforms are a hotbed for airborne pollutants. Though many people may not spend long lengths of time at a subway station, those that use the subway to commute to work every day can be consistently exposed to pollutants from subway train engines, as well as those carried in by ventilation systems and other passengers. Particulate matter and airborne bacteria are two of the primary airborne pollutants found in subway stations (Xu & Hao, 2017).

Protect yourself from airborne pollutants when out in public

It may not be possible to avoid the above indoor air quality concerns altogether, but you can still take steps to reduce your exposure to harmful airborne pollutants. Try limiting the amount of time that you spend in places known to be indoor air quality offenders and choosing well-ventilated alternatives whenever possible. For buildings with high levels of particulate matter, such as hospitals, train stations and subways, you can wear a N95 mask to trap some of the pollutants before you breathe them in. If you are visiting a doctor’s office, wearing a surgical mask might prevent the spread of liquid droplets from coughs and sneezes (be aware, however, that the jury is still out on the efficacy of facemasks in general when it comes to protecting the wearer from germs and pollution). If you are worried about the air quality in a school or office building, you can talk to the appropriate administrator to make sure that HVAC systems are properly maintained, including regular filter replacement.