[caption id="attachment_2325" align="aligncenter" width="1000"]The view from our apartment in Seoul. Some days are better than others. The view from our apartment in Seoul. Some days are better than others.[/caption]

The air quality in Seoul — a mega city home to 70,000 taxis and 10 million residents — can get rough at times, especially for people already sensitive to pollution. It's been an adjustment for my family, though it could be worse.

We could live in Beijing or Shanghai.

This chart, from a recent work collaboration with my wife, shows the number of days in 2015 that the pollutant PM2.5 reached certain health thresholds in the U.S. Environmental Protection Agency's air quality index. It compares Seoul to Beijing and Shanghai in China and New York and Los Angeles in the U.S.

Seoul isn't terrible — but it isn't great, either:

air-quality-days

This chart, also from the project and inspired by Katie Park's recent work on pollution about New Dehli, shows the maximum, minimum and average air quality index levels by day in Seoul last year. Again, the air often hovers around mediocre:

air-quality

And, finally, this chart shows the air quality daily average last year in Seoul compared with New York City. The difference is clear:

air-quality-seoul-nyc

Thanks to Alyson Hurt and the NPR Visuals team for letting me work on the story.