Air pollution in China could be big business.
Bouts of acrid smog enveloping Beijing prompted authorities in the Chinese capital to declare two unprecedented "red alerts" this month - a warning to the city's 22 million inhabitants that heavy pollution is expected for more than three days.
Such alerts rely on advances in pollution forecasting, increasingly important for Communist Party leaders as they seek improvements in monitoring and managing the country's notorious smog in response to growing public awareness.
Official interest has also been boosted by China's preparations to host the Winter Olympics - Beijing's smog is worse in the colder months - in 2022.
"There is increasing attention to the air quality forecast service," said Yu Zheng, a researcher at Microsoft. "More and more people care about this information technology."
A rudimentary forecast was pioneered by Dustin Grzesik, a U.S. geochemist and former Beijing resident who created Banshirne.com, a free website and smartphone app, in 2013 to predict clean air days using publicly available weather data on wind patterns.