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The author:(作者)aaapublished in(发表于) 2014/7/16 9:10:50 Beijing， Tianjin and Hebei for 3 months no serious pollution
Washington (by Zou Chunxia) in June, the air quality days nearly half of Beijing, Tianjin and Hebei, have improved compared to last month, all-weather months no serious pollution. Integrated first-half figures, from January to June this year, the standard increases month by month the number of days of Beijing-Tianjin-Hebei, consecutive March weather no serious pollution.
Worst top ten selected cities of Beijing and Tianjin and Hebei to reduce
Ministry of environmental protection the air report released yesterday showed that in June, the national average standard of 74 cities in the number of days is 69.9%, with 1.8% lower compared to the same period last year, exceeding the number of days of severe pollution and above is 2.3%. Urumqi, Haikou, Guiyang, Kunming, Xiamen, June 5 cities such as air quality and 100% standards.
Air quality is relatively poor in June's top 10 city is Tangshan, Nanjing, Shijiazhuang, xingtai, Baoding and Handan, Wuhan, Jinan, Xuzhou, Suqian. Last month, there are 3 cities in Jiangsu Province selected the worst top ten, still ranks as the worst in Nanjing, capital of the top three.
6 the Ministry of environmental protection in the first half air "black list" ranking, shortlisted cities of Beijing, Tianjin and Hebei in the past two months has decreased, are 5 seats, after monthly at least 6 cities of Beijing, Tianjin and Hebei were selected, April 9 cities in the list. In addition, the worst air in the country last year, Shijiazhuang, air improved significantly in the first half of this year, the first half of Shijiazhuang on 6 "black list", but have never been ranked.
Beijing, Tianjin and Hebei in June, air quality improved
In June, the three regions in the Yangtze River Delta, Pearl River Delta regional air quality has declined, only Beijing, Tianjin and Hebei area air quality had improved.
13 cities of Beijing, Tianjin and Hebei, days of average air quality standards for 48.5%, compared with the previous month increased by 5%, air quality has improved. Exceed the number of days in the proportion of severe pollution and above 3.2%, 0.9% above the 74 cities, but no serious pollution.
Looking at the data in the first half, Beijing, Tianjin and Hebei 25.4% of the standard number of days from January, measuring up to June 48.5%, while heavy pollution days decreased from 23% to 3.2%, heavy pollution weather only appeared in the first quarter.
However, it is worth noting that, in June, and ozone pollutants in Beijing, Tianjin and Hebei in the first place for the first time this year. In May, the Beijing-Tianjin-Hebei PM10 is the primary pollutant, Beijing municipal environmental protection Bureau has on air quality in the first half of that due to outside dust this year are more frequent and the local effects of dust, PM10 improving trend was slower.
Interpretation
Ozone can cause elevated PM2.5 concentrations harm the respiratory system
Just this past June, Sky made an impression on people, why do we have a situation of excess ozone?
Vice Dean of College of environmental sciences and engineering Xie Shaodong told Beijing Youth daily reporter, ozone and PM2.5, PM2.5 is a tiny particles will affect the scattering of light reduced visibility, ozone did not affect visibility. Visibility was good, the Sun is very good, but is conducive to the formation of ozone.
He said that ozone is a secondary pollutant, nitrogen dioxide and volatile organic compounds by chemical reaction. One of the reaction conditions, UV radiation, so in good light circumstances, are particularly vulnerable to generate ozone.
In accordance with the new standard, 8-hour average ozone concentrations below the 160 micrograms/cubic meter, the air quality is a priority, 160-200 μg/m3 as well, more than 200 micrograms/cubic meter is caused by pollution.
Reason for ozone pollutant, said Xie Shaodong, ozone because of its strong oxidizing, will in itself have an impact on human health, such as eye, nose, throat, respiratory tract irritation. In addition, he noted that ozone is an oxidizer and will help other substances into PM2.5, and high conversion speed faster and more.
In fact, not only in June, the Beijing air quality report released by the municipal environmental protection Bureau in early 2013 show 2013 189 pollution in Beijing-China, 20.1% is because of excessive ozone ozone exceeded mainly occurs from May to September.
Xie Shaodong, ultraviolet rays like the ignitor, the air has a lot of natural substances can produce nitrogen dioxide and volatile organic compounds, but insufficient sunlight in the winter, ultraviolet light is not enough, points up, summer, sunny, so the ozone standard will show a seasonal.
Text/reporter Zou Chunxia
(Original title: Beijing, Tianjin and Hebei in March in a row no serious contamination)
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