Inspired by Mitch’s article “The Case for Data Visualization,” I decided to utilize a visualization to represent and compare Beijing’s PM 2.5 levels with various international cities (According to the EPA, PM 2.5 is the term for fine particles, the smallest and most dangerous of particulate matter as they can become deeply lodged into lungs). I selected Shanghai, Delhi (one of the world’s most polluted cities), Mexico City, Los Angeles (one of the United States’ most polluted cities) and Alexandria, Virginia (the PM 2.5 monitoring system closest to my home).

After collecting, cleaning and formatting the data, I plotted each city’s weekly max PM 2.5 reading from January 1st 2013 to April 30th 2016. I used Tableau to explore and create clear and visually appealing data visualizations. While weekly, monthly, or yearly views are far less granular than the daily max reading, they allow the user to better distinguish the various cities’ data.

For reference, the EPA has divided the AQI into seven categories: Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, Hazardous, and Beyond the AQI. “Good AQI” is a PM 2.5 reading of 0 to 50. At this level, the pollution poses no risk to people outside. “Very Unhealthy AQI,” however, is 201 to 300. This level of air pollution would present an environment where “everyone may experience more serious health effects.” An AQI above 500 is defined as “Beyond the AQI” and is extremely dangerous for one’s health. With these AQI categories in mind, the results are staggering.

Below are histograms of the cities’ weekly max levels from January 2013 to April 2016 in terms of the seven EPA AQI categories.