When Frank Hammas first came to China, the main market for the air purifiers his company sold was from hospitals and other institutions. Today, Switzerland-based IQAir has a booming consumer business, thanks to public concern over air quality that has created a global market out of a Beijing obsession.

Individual action and public policy are helping shape the response to the transformation of China, the most prolific consumer of polluting fossil fuels, and the health crisis that incurs.

The metamorphosis of anti-pollution devices into household goods stems from the “crazy bad” air quality in Beijing over the past decade, and a US embassy monitor that turned air pollution into a matter of public concern. Once developed for anxious Chinese consumers, such gadgets have found new niches from South Korea to Europe.