Beijing among most polluted cities for first time this year
Updated: 2015-08-18 07:31
By ZHENG JINRAN(China Daily)
|
|||||||||
Two students wait for a school bus at a stop with an air purification device at Tsinghua University in Beijing in July. The apparatus was designed for outdoor air cleaning and has already been tested for four months at a bus stop in Hong Kong. CHINA DAILY |
Beijing was among the worst 10 cities in China for air quality in July, the first time this year the capital has dropped so low.
Only 35.5 percent of days in the month met the national standard, putting the capital at 65th among the country's 74 major cities.
According to the Ministry of Environmental Protection's monthly air quality report on Monday, most of the polluted days registered excessive ozone concentration.
Excessive concentrations of ozone can cause respiratory tract irritation, damage to the body's immune system and affect lung function. Health experts strongly suggest that people stay indoors around noon to avoid the worst of such pollution.
The maximum concentration in eight hours surpassed the national standard by 58.1 percent, 13.3 percent points higher than the maximum in June, Luo Yi, head of environmental supervision at the ministry, said.
The ministry report said six cities in Hebei province, which neighbors Beijing, were among the worst 10 in China for severe air pollution in July, of which the city of Xingtai was the most polluted.
Except for the higher ozone concentration, the capital has seen a year-on-year decrease of other major air pollutants. Sulfur dioxide has dropped by 28.6 percent, and PM2.5-particulate matter with a diameter smaller than 2.5 microns-fell by 31.9 percent, the monthly report said.
Unlike excessive particulate matter in the air, which makes the days smoggy, excessive ozone concentration can occur under blue skies.
Excessive ozone concentration in the air refers to the ozone in the land surface layer, which is mainly generated after complicated photochemical reactions, said Chen Nianliang, a researcher at the Beijing Municipal Environmental Monitoring Center.
Ozone concentration is affected by the excessive emission of nitrogen oxides and volatile organic compounds, which are the major pollutants from vehicle exhaust, coal burning and emissions from chemical industries, Chen added.
Additionally, strong sunshine and high temperatures speed up photochemical reactions, meaning ozone concentration is at its highest from May to September, he said.
It is difficult to take targeted measures to reduce ozone because of its complicated relationship with the other pollutants, he said.
The ministry said most of the polluted days in major cities in the Yangtze River Delta and Pearl River Delta regions such as Shanghai and Guangzhou were because of excessive ozone concentration.
The inland province of Shaanxi also saw severe ozone pollution in July.
- Pollution rules aim at accountability measures
- Air quality worsens after explosion in Tianjin
- 9.4 trillion yuan pledged to fight water, air pollution
- China does not have a pollution problem
- Network to boost pollution monitoring
- Ministry names and shames northern city for pollution
- Beijing promises better air quality and enough snow for Winter Games
- Some Suggestions on Deepening the Reform of China's Monitoring System for Ambient Air Quality
- Beijing’s air quality slides in June
- Ceremony held on seventh day of Tianjin blasts to mourn victims
- Beijing ready for IAAF World Championships
- Silk Road city displays sculptures at exhibition
- Top 10 companies with the most employees
- Men in Indonesia climb greased poles to win prizes
- In pictures: Life near Tianjin blasts site
- The world in photos: Aug 10-16
- In the face of chaos, people persevere
Most Viewed
Editor's Picks
Seventh China-US strategic dialogue |
Premier Li embarks on Latin America visit |
What do we know about AIIB |
Full coverage of Boao Forum for Asia |
Annual legislative and political advisory sessions |
Spring Festival trends reflect a changing China |
Today's Top News
Anti-corruption campaign 'good for China, US'
Rain in Tianjin poses no health risk, says official
Two HK women among four Chinese killed in Bangkok blast
Buffett bets on Chinese tourists with Precision Castparts deal
Bomb in centre of Thai capital kills at least 12
'Window' on WWII opens in Bay Area
US pilot is remembered in book, film
Sodium cyanide in Tianjin to be collected, neutralized
US Weekly
Geared to go |
The place to be |