The team then expanded it to include over 120 cities in the nation, with air quality data pulled from the U.S. Embassy and pollution monitors of China's Ministry of Environmental Protection. In total, the app has reached over 1 million downloads, most of them for iOS. Earlier this month, the company released an Android version.
Longcat Labs, another developer behind an air quality monitoring app for Beijing and Shanghai, said it also noticed a spike in downloads since Jan. 11. Downloads have tripled to about 100 per day, the company said in an email.
In the future, Wang's startup plans to continue improving its app, and will consider monitoring the air using its own equipment if its team can find an inexpensive solution.
He added that he thought it was ironic that his app succeeds when Beijing's pollution worsens.
"It's really weird. We are thinking about leaving Beijing," he said. "Our product is good, but the environment around us is getting worse."