My mother-in-law used to be obsessed with the smell of air freshener. Whenever we visited her, every bathroom and bedroom would be equipped with various sprays, scents and room deodorizers. Once I awakened in the night to something being sprayed in the room. In the morning, I figured out what it was: A new spray gadget set to spritz air freshener into the room hourly.

But here’s the thing: Aerosol air fresheners contribute to, rather than reduce, indoor air pollution, according to the Environmental Protection Agency (EPA). “In general, the chemicals that create the aerosol effect are bad for the environment, in particular the ozone,” says Stewart Lonky, an expert in biological toxicity and author of “Invisible Killers: The Truth about Environmental Genocide.”

“Have you read the ingredient labels on most air fresheners?” asks K.B. Lee, founder and CEO of Ever Bamboo, a company that promotes natural ways to neutralize odors. Chances are you’d see fragrance or perfume on the list, and that single ingredient could contain up to 400 more ingredients, some of them toxic. Aerosol sprays also contain chemicals like formaldehyde and xylene, so you’re “freshening” with toxins.

“These ingredients are carcinogens and neurotoxins harmful to our bodies, children and pets,” says Lee. There are real risks, especially with hair sprays and air fresheners, which can send formaldehyde and other volatile organic compounds (VOCs) not only into the air, but also onto surfaces throughout your home.

“Once on surfaces, these toxins can get on your hands,” and from there, of course, they can get into your mouth. Says Lonky. “This method of intake is often more harmful and ubiquitous than many people realize.” For example, aerosol spray paint may contain methylene chloride, which is known to cause cancer in animals, according to the Consumer Product Safety Commission. And if you ingest it, your body converts it to carbon monoxide and can cause symptoms associated with carbon monoxide exposure.

What aerosol does to the environment

Even more dismaying is how aerosols, which are tiny particles suspended in gas, are affecting the climate. According to a new MIT study published in Geophysical Research Letters, they may be altering rainfall. "While it is true that total precipitation change is controlled by average global temperature change, … our research shows that aerosols have significantly impacted the distribution of precipitation change around the world since preindustrial times," said Chien Wang, a senior research scientist at the MIT Joint Program on the Science and Policy of Global Change and the MIT Department of Earth, Atmospheric and Planetary Sciences.

NASA explains how aerosols can affect the rain:

“Aerosols are thought to suppress precipitation because the particles decrease the size of water droplets in clouds. However, under some environmental conditions, aerosols can lead to taller clouds that are more likely to produce lightning and strong downpours. In a few places, meteorologists have even detected a cycle in which the frequency of thunderstorms is connected to mid-week peaks in aerosol emissions.”

Many people associate aerosol sprays with damaging the ozone layer. But companies eliminated ozone-depleting chemicals, also known as chlorofluorocarbons (CFC), back in the ‘70s. Most aerosol products made or sold in the U.S. now use propellants — such as hydrocarbons and compressed gases like nitrous oxide — that do not deplete the ozone layer.

However, that doesn’t make aerosols safe. Every time you spritz an aerosol, you raise your carbon footprint because they contain hydrocarbon and compressed gasses. In fact, today’s CFC-free aerosols also emit VOCs that contribute to ground-level ozone levels, a key cog in asthma-inducing smog.

Aerosol cans that contained hazardous products like paints or bug sprays should be disposed as hazardous waste. Aerosol cans that contained hazardous products like paints or bug sprays should be disposed as hazardous waste. (Photo: Huguette Roe/Shutterstock)

Reducing aerosol usage

The EPA suggests avoiding aerosols when possible. But if you have to use an aerosol spray, they offer these tips:

  • Carefully estimate the amount of product you need to complete a particular job and buy only that much. Avoid “super” sizes or bundled aerosol products.
  • Skip products that are sprayed directly on the body like sunscreen, hair spray and deodorant. Choose non-spray options, like creams or a pump spritz, instead.
  • Avoid any spray-freshening product. Just open your windows to improve air circulation and freshen indoor air.

Green disposal

If you have empty aerosol cans, recycle punctured cans with scrap metal or in a separate community program specified for aerosols. If the can held hazardous waste products like paint or solvents, or still has product left, it must be treated as hazardous waste, the EPA says. Contact your local waste management office for more information on hazardous waste disposal in your area.