I was concerned about air pollution in my home for a similar reason! When I looked out my window in Beijing, I saw this:I’m kind of one those “I’ve got to see it for myself” guys, so I bought testing equipment and started doing tests in my home. So what did the data say? First, let’s break down air pollution into two components: particulate pollution and gas pollution.The article linked above mentions coal particles. Coal and other dangerous particles are in the air we breathe, and they have not-so-fun health effects (What is PM 2.5 in air? What are the dangers of air pollution?).Fortunately, particles are easy to get rid of! HEPA filters are common in vacuums and purifiers, and they were invented back in the 1940s during the Manhattan Project. That means they’re reliable, not patented, and relatively cheap. I made simple do-it-yourself purifiers in my apartment in Beijing (instructions here) and then used a laser particle counter to see if they could reduce the amount of particulate in my bedroom.

Here’s what it happened to particulate levels after I turned on the purifier. The red line is outdoor air pollution.(For fellow nerds, all my test data and methods are open source.)Of course, you don’t have to do it yourself! Empirical tests of many different purifiers have found that many can significantly reduce particulate levels indoors. (Just make sure to avoid ionizers.) I list several sources of test data in this answer: What is the best air purifier on the market today?HEPA filters capture particles, but cars also put out gas pollution, such as NO2 and SO2. For those pollutants, we’re going to need something different.Activated carbon (also called “charcoal”) can help reduce harmful pollutants. Gases are harder to test for, and the studies of gases are fewer, but there is easily enough science on activated carbon to know that it can reduce harmful gas pollutants.In my apartment in Beijing, I tested whether carbon could capture volatile organic compounds (VOCs), a type of gas pollutant.

Here’s what the data from one test looked like. electrostatic air cleaner how it worksThe blue line is a fan + carbon filter; air purifier gets rid of smellsthe red line is a fan-only condition.air purifier gadget showNerd alert: the raw data and methods are available here:Can Activated Carbon Remove Formaldehyde?With a good particle filter and gas filter, you should be able to lower your family’s exposure to air pollution. You might also consider getting a home test to see if the pollution is anywhere near the level you’d want to be concerned about.The air in your home may not be as fresh as you think it is. If you’re not careful, indoor air can harbor not only benign entities, such as mustiness or a foul odor, but also bona fide pollutants that can exacerbate allergies and negatively impact your health over the long term.

The U.S. Environmental Protection Agency (EPA) cites a long list of contaminants that are commonly found in households around the country. These include, among other things, smoke (from tobacco or cooking), dust, mold and mildew, and emissions from combustion sources (oil, gas, kerosene, coal, and wood), not to mention pollution from building materials and furnishings—paint, insulation, carpeting, and pressed wood among them. To protect yourself and your family from the legitimate threats to health posed by any of these indoor pollutants, the EPA recommends two courses of action: Prioritize good ventilation, and eliminate pollutants through the use of an air cleaner (also known as an air purifier). These appliances are designed to do one thing only, and that is to directly remove toxins from circulation. Indoor air quality takes on paramount importance during heating and cooling seasons, when homeowners tend to keep the windows closed, and natural ventilation comes to a standstill.

“The air circulating through your home can be full of dust, dander, mold, and other unpleasant particulates that can affect you negatively. An in-line cleaner blocks these particles from continuing to go around your ductwork and into the air you breathe. It also helps keep these particles from getting into your heating and cooling equipment, which could help prevent costly problems down the line.” The in-line air cleaner O’Brian refers to is related to, but much more powerful and sophisticated than, the air purifiers you’ve seen in your local home center. Those small, portable units can be reasonably effective in one room, but people don’t live in just one room. Although you could buy a portable unit for every room on every floor of your house, the better investment is a single, larger model that can serve the whole house. Most such air cleaners attach to your existing HVAC system, but that’s where their similarities begin and end. and other leading distributors offer a range of whole-house air cleaners that use different methods to remove airborne contaminants.

Here’s a rundown of the most common air-cleaning technologies: • Electrostatic attraction: Air flows through an ionized sector within the filter. Here, particles are imbued with an electrical charge. The charged particles accumulate on a series of flat plates in an oppositely charged collector. The particles are neutralized, leaving clean air to flow out from the appliance. • Ion generation: These air cleaners work similarly to electrostatic devices. Ionizers disperse charged ions into the air, which attach to airborne particles, giving them a charge so that they attach to nearby surfaces (for example, walls and furniture). These charged particles are then cleaned up in the course of everyday housekeeping. • HEPA filtration: When combined with a forced-air furnace or air handler, a HEPA filter-based purifier passes air through a series of filters, each of which plays a role in capturing impurities. There are also HEPA systems that run independently of the HVAC system.