Breathing easier in the big city

Dear Alice,

I have noticed the air quality is very bad here in New York City. I was thinking of buying a humidifier so that I could breathe cleaner air at night. Would hot steam or cold steam be better? Do you think this would make a difference for my lungs?

Thank you,
Needs Clean Air

Dear Needs Clean Air, 

It's true that New York City (NYC) is no Kahului-Wailuku-Lahaina, Hawaii which is ranked as the cleanest metropolitan area in the United States (US) as of 2023 by the American Lung Association. Some good news is that NYC is no longer ranked as one of the 25 most polluted places to live in the US and has shown improvements in addressing air quality. When it comes to considering ways to clean the air in your living space, a humidifier likely won't make a difference for your struggling lungs. Instead, you might choose to explore different types of air purifiers (more on these in a bit). 

Humidifiers don't actually clean the air, instead, they add warm or cool moisture. This increase in humidity can help prevent dry skin, noses, and throats, especially when exposed to heated air during the cold months. Humidifiers can also make it more comfortable for those with colds or sore throats to breathe—but they don’t cure these illnesses, nor do they purify the air. The U.S. Environmental Protection Agency (EPA) has information about the use and care of home humidifiers on its website, including comparisons between warm and cool mist units. 

Air purifiers—also called air cleaners—especially high efficiency particulate air (HEPA) filters that can remove microscopic particles might be more in line with what you’re looking for. Air purifiers can make the air cleaner and are sometimes recommended for people with asthma or severe allergies. However, they can be expensive (those with HEPA filters can cost hundreds of dollars), need to be cleaned frequently (about every 2 to 3 months depending on usage), and need to be the right size for your room if they're going to continue to work at maximum efficiency. That said, there are a few factors you might consider when choosing a portable air cleaner: 

  • The clean air delivery rate (CADR) is a measure of the number of particles a portable air cleaner can filter. The device's packaging usually gives you an indication of the largest room that the air cleaner could most effectively clean based on its CADR; air cleaners with higher CADR scores usually also have HEPA filters. 
  • The type of filter included in the air cleaner is important to note for gas filtration, while the CADR only indicates the level of particle filtration. While activated carbon filters can filter gases, any filter type that can filter gases is recommended. 
  • The fan speed and run time of your air cleaner will change how much air is being filtered. Higher fan speeds and longer run times often filter more air. 
  • If you have a furnace or heating, ventilation, and air conditioning (HVAC) system, there are filters available to purchase to remove particles with varying levels of efficiency, but these tend to only work when the HVAC system is running (that’s to say, when heating or cooling is needed in the space). A professional HVAC technician may be able to help you decide what’s the most efficient filter to use for your furnace or HVAC system. 

While owning an air filter won't hurt, limited evidence exists to suggest that they offer significant health benefits for people who don't already have breathing problems. You might enjoy knowing that on a federal scale, some work is being done to improve air quality, beyond just telling everyone to grab an air purifier or other device. In 1970, the Clean Air Act was passed to tackle air pollution in the US, mainly by placing restrictions on dangerous air pollution. This did lead to some improvements, like better visibility, and fewer instances of acid rain. However, air pollution continues to be a serious environmental, health, and financial burden to the US and the world. 

If you're interested in learning more about the air quality in your city, check out AirNow before heading out the door. The AirNow website allows you to view daily updates on what the air quality is in your zip code, city, or state. To prepare for days when the air quality is less than ideal, you might consider checking out the American Lung Association’s 10 Tips to Protect Yourself from Unhealthy Air. 

All that said, if you find that purchasing a humidifier or an air filter helps you breathe easier, great! In addition, you may also find that potted plants, although they're not enough to drastically improve air quality, might lend your bedroom the illusion of "greener pastures," so to speak. Consider experimenting with a couple of things in your surroundings, and if nothing helps, consider visiting a medical professional to get a more tailored solution for any discomforts you’re experiencing.  

Last updated Jul 07, 2023
Originally published Apr 27, 2001