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.

Statistics from All View Cloud, a Beijing-based data analysis company, showed total turnover of air purifier companies reached 5.81 billion yuan ($907 million) in the first half of the year, a 20.5 percent year-on-year fall, with sales volumes down by 10 percent.

"Based on air quality statistics from many parts of the country, air pollution has eased somewhat, along with the urgency to buy air purifiers," Liu Buchen, a home appliance market expert, was quoted by the National Business Daily as saying. He said high inventories by purifier manufacturers also caused the drop in the industry's growth rate.

According to China Market Monitor, 5.1 million air purifiers were sold across the country last year.

Zuo Yanque, its brand director, said: "Competition in the market also surged after a rise in the number of brands and products. The market shares of the top five brands have fallen year-on-year as have offline sales, which dropped from 90 percent of the total in 2010 to 70 percent in 2015."

The quality of air-purifying products available has fallen too, according to Chen Jianbo, an analyst with All View Cloud.

A new national standard on air purifiers is expected to be issued by the authorities in the second half of this year to bring order to the market.

"A shift in the air purifier market has begun. Although around 280 new air purifier brands entered the market, around 230 have actually fallen by the wayside."

Dino Asvaintra, vice-president and general manager of Honeywell Connected Home Global High Growth Regions, a technology manufacturer which also produces purifiers, is optimistic, insisting the Chinese market still has huge potential and can expect steady long-term growth.

"The penetration rate for air purifiers in China is still very low. The drop in sales is because the first set of consumers have just made the purchases.

"I believe more and more consumers will buy air purifiers in the near future," he said.

He is looking forward to the upcoming new national standards which he said would make the market more trustworthy.

Sam Li, managing director in China of Blueair AB, a Swedish air purifier manufacturer, said that sales of its products this year were lower than anticipated, but its actual target is unchanged.

He blamed the decline more on the overall economic downturn and some producers exaggerating the performance of their products and misleading consumers.

He did not agree, as some have suggested, the industry has entered a "cold winter", insisting as the awareness of air pollution rises, so will sales again.

"Although air quality of many cities in China has improved this year, pollution control is a long-term policy and the current air quality standard in China is much lower than the standards applied in the United States and Europe."