Improving air quality has resulted in a sharp drop in air purifier sales in the first half of the year.

According to a report from China Market Monitor Co Ltd, the market researcher and information provider, the sales declined 18 percent in the period, which it attributed to the quality of air in cities getting better.

The study also estimated the air purifier market will drop 13.1 percent in value this year, indictating a virtual end to what has been a boom time for producers.