www射-国产免费一级-欧美福利-亚洲成人福利-成人一区在线观看-亚州成人

USEUROPEAFRICAASIA 中文雙語Fran?ais
China
Home / China / Society

Mist cannon among tools used to fight heavy smog

By Zheng Jinran | China Daily | Updated: 2016-12-05 07:37

Heavy smog that has been covering many cities in northern China has caused some authorities to bring out pollution-fighting artillery.

The mist cannon, which is not well-known but gaining popularity, is a large machine mounted on a truck that sprays water mist.

They were initially used at construction sites and mines to reduce dust. But engineers have improved the machines to make them release tinier droplets of mist for combating fine airborne particles, said Xu Yuexin, an engineer with Beijing Capital Group Boom-sound Environment Science & Technology Co Ltd, which provides the mist cannon service in parts of the capital.

"The truck works by nebulizing water into tiny particles, with diameters in microns, the same as PM2.5 and PM10, and spraying them into the air, and then they could combine with the dust and fine particles to fall to the ground," Xu said.

Experts have found they're effective, but have their limits. They are, officials said, only one of the measures being taken. Tough restrictions on emissions is still the best way to control air pollution for the longer term.

Beijing residents woke up to thick smog over the weekend, with the air pollution readings of 21 monitoring stations climbing to the most hazardous level in the early hours of Sunday. The visibility was reduced to within 500 meters in some areas.

The smog, which also covered vast areas of the country's north, was mainly a product of windless weather that was unable to disperse pollutants, according to environmental authorities in the affected areas.

The capital issued its second-highest warning against air pollution, an orange alert, on Thursday, one day before smog covered the city. Under an orange alert, the capital takes comprehensive measures to control the emissions from companies, vehicles and construction sites.

Implementation of restrictions under the alerts has been strengthened, officials said. In Beijing on Sunday, the alert prompted inspectors to monitor 533 companies and construction sites, and check over 57,800 vehicles, the municipal environmental bureau said.

The mist cannon trucks are being used to spray in the mornings, and do so more frequently, some three to five times, during smoggy days.

Authorities also spray special chemicals on the roads through regular watering vehicles once a week. The spray absorbs and consolidates the dust and pollutants from vehicle exhaust, Xu said.

The combination of the mist cannon and the chemicals "have been determined effective in reducing the fine particles", Xu said.

According to tests conducted by researchers with the China National Environmental Monitoring Center, the mist cannon and the chemicals can together "cut the PM10 by 20 percent, PM2.5 by 5 percent and nitrogen oxides by 10 percent", according to Xu.

There are two trucks covering 35 streets in the capital's Chaoyang district, mainly around the Olympic venues and regions where embassies are concentrated, because of the high population densities and frequency of events. The trucks started operating in October and plans call for them to continue to April 2017.

Li Gang, from the company's marketing department, said that additional districts in Beijing and other cities may adopt the services if the mist and chemicals perform well.

Many cities in northern China, including Xi'an in Shaanxi province and Zhangjiakou in Hebei province, have used mist cannons since 2014. There also is interest in them from cities this year such as Chengdu in Sichuan province and cities in Hunan province, officials said.

But Shi Guoliang, associate professor of environmental sciences at Nankai University in Tianjin, said, "The mist cannon did work in reducing the particles, but worked only for a limited time and region, yet it's better than doing nothing."

The government should pay more attention to implementing measures to cut the emissions at their source, he added.

zhengjinran@chinadaily.com.cn

Editor's picks
Copyright 1995 - . All rights reserved. The content (including but not limited to text, photo, multimedia information, etc) published in this site belongs to China Daily Information Co (CDIC). Without written authorization from CDIC, such content shall not be republished or used in any form. Note: Browsers with 1024*768 or higher resolution are suggested for this site.
License for publishing multimedia online 0108263

Registration Number: 130349
FOLLOW US
 
主站蜘蛛池模板: 亚洲精品久久久中文字 | 怡红院成人在线 | 91网站在线免费观看 | 性感一级毛片 | 亚洲欧美日韩精品高清 | 日韩欧美国产一区二区三区 | 99热久久国产这里是精品 | 日韩国产欧美精品综合二区 | 亚洲福利视频精选在线视频 | 久久91亚洲精品中文字幕 | 黄a免费| 一级特黄aaa大片在线观看 | 国产在线播放不卡 | 免费看欧美xxx片 | 日韩毛片在线播放 | 久久大陆| 最刺激黄a大片免费网站 | 午夜视频国产 | 在线亚洲精品视频 | www亚洲免费 | 亚洲精品456在线播放无广告 | 国产黄色大片网站 | 日韩精品另类天天更新影院 | 性做久久久久久免费观看 | 欧美成人毛片 | 亚洲精品不卡在线 | 午夜性刺激免费视频观看不卡专区 | 色爽爽爽爽爽爽爽爽 | 欧美国产合集在线视频 | 免费一级成人毛片 | 欧美精品高清在线观看 | 日韩在线观看一区 | 亚洲自拍中文 | 欧美综合视频在线观看 | 欧美成人精品高清在线播放 | 国产午夜毛片一区二区三区 | 在线观看自拍视频 | 高清波多野结衣一区二区三区 | 92看片淫黄大片看国产片 | 欧美日韩精品一区二区免费看 | 普通话对白国产精品一级毛片 |