Continue Shopping
Estimated Total
View cart Checkout
mountains with clouds in background

How does your city rank for air quality?

A lot goes into deciding where you live. Job prospects, crime rate, and proximity of family and friends tend to be the first things that come to mind. But there is another important aspect to consider: air quality. This is especially important for those with asthma or allergies, but anyone can be affected by the consequences of poor air quality.

So, how does your city stack up? We’ve listed the five most polluted cities by year-round particle pollution, determined by the American Lung Association’s “State of the Air 2017” report. This measures the annual average particle pollution (both solid and liquid) within a city, giving a holistic view of pollution for a specific location across time. Unfortunately, all five of these cities have pollution levels above the national standard determined by the EPA:

5. Los Angeles, CA

4. San Jose/San Francisco/Oakland, CA

3. Fresno/Madera, CA

2. Bakersfield, CA

1. Visalia/Porterville/Hanford, CA

The news isn’t great for the Golden State. As you may have surmised, California is the lowest ranked state for air quality, according to the United Health Foundation (with Pennsylvania and Illinois following as 2nd and 3rd most polluted). On the other end of the spectrum, however, Cheyenne, WY reigns supreme as the cleanest city for year-round particle pollution.

So, what if you live in one of these polluted areas, and a move to Wyoming just isn’t for you? If you can’t change the air outside, you can influence the air inside your home.

First, you can keep windows closed and make sure they’re sealed properly to keep polluted air from creeping in. Then, you can make sure to keep your home clean to prevent dander, dust, or mould from building up. Finally, you can use an air purifier with a HEPA filter to catch 99.97% of particulate matter in the air. It’s a little bit like having air pumped directly form the Grand Tetons into your home.


1Coway air purifiers has been proven to trap dust, pollen, dander, viruses and bacteria in the air based on KCL (Korea Conformity Laboratories) testing.They have been tested in a 30㎥ size chamber according to the Korea Air Cleaning Association standard (SPS-KACA 002-132:2022 Modified) to measure the 0.01㎛ size of particle removal rate. It was tested on maximum airflow speed in normal room temperature and humidity conditions. The performance may vary in the actual living environment of customers.
→ Tested with Airmega Aim, 150, 160, AP-1216L, AP-1512HH, AP-1512HHS, 200M, Icon, IconS, 230, 240, 250, 250 Art, 250S, 300, 300S, 400, 400S, ProX

299.97% of viruses, bacteria, fungi and pollen were verified to be removed from the air for Coway air purifiers which have Green True HEPA™ filter applied based on the Japan Food Research Laboratories(JFRL) testing according to JEM 1467 standard.
→ Tested with Coway Airmega AP-1512HH, AP-1512HHS, 250, 250 Art, 250S, 300, 300S, 400, 400S
→ All tested by JFRL and received above result within below time.

All tested by JFRL and received above result within below time.

- Virus: Tested with Escherichia coli phage ΦX174 NBRC 103405, 60 minutes
- Bacteria: Tested with Staphylococcus epidermidis NBRC 12993, 60 minutes
- Fungi/Mold: Tested with Penicillium citrinum NBRC 6352, 60 minutes
- Pollen: Tested with Cedar Pollen extract, 60 minutes

3Aerosol test conducted in a Biosafety level 3 laboratory with two Coway air purifier models, Coway Airmega 250 and 400 for removal of SARS-CoV-2 Aerosol by US based MRI Global, a not-for-profit laboratory and partner of US Department of Defense. The test was conducted in a 13.1ft3 chamber. Virus was aerosolized for 15 minutes and the product was turned on high for 2 minutes. Result showed each product effectively removed over 99.98% of the SARS-CoV-2 in 2 minutes. This is a result from a laboratory experiment condition and result may vary in different conditions. This result does not imply it kills SARS-CoV-2 or prevents the transmission of Covid-19. Coway Airmega 250S and 400S are identical to the tested models and has equal performance with an additional mobile connectivity function.

4The concentration of ammonia, acetaldehyde and acetic acid were proven to be removed within 30 minutes by FCG Research Institute, Inc. Human Life Science Lab. It is not a demonstration result in the actual use space. Not all odors and gases may be supported. → Tested with Coway Airmega 150, 160, AP-1512HH, AP-1512HHS, 400, 400S

5The coverage area of the air purifier is based on an area where the air cleaner can make two air changes per hour (ACPH). An air change per hour translates to how many times an air purifier can clean an area, assuming the height of a ceiling to be 8 ft, in one hour. Therefore ** means two air changes per hour means that the cleaner can clean the area once every 30 minutes and * means air changes per hour means that the air purifier can clean the area once every 60 minutes.

10Terms and conditions apply. Discounts, including promotions, coupons, bundle discount and subscription discount, cannot be stacked on top of other coupons. During promotional periods, discount codes will not be able to be applied to orders. Promo codes may apply to products only—filters, accessories, and new products within 3 months of the release date are not included.