Yesterday, the light bridge was a blind spot. When the fog of the city continued. Newsman yoon ya fei
In january this year, parts of the central east, north-east and south-west of the country were subjected to severe haze processes involving more than 800 million people. Beijing has suffered four consecutive haze processes, the first of which was the worst since the new century。
“on the last 31 days, 22 days of air quality supranational 2 standard, 27 days of supernational 1 standard, 4 days without masks, only one day comparable to that of europe and free breathing outside.” wang marx, researcher at the institute of atmospheric physics of the central college of sciences。
According to them, in january, four haze contamination processes occurred in the kyinzu region, and only four days in beijing were good weather. According to the pm2. 5 analysis in its unit, the maximum pm2. 5 hour concentration in beijing was 1000 ug/m3 and 120 hours exceeded 300 ug/m3。
From its analysis, kyouta looks forward to these four “silent” processes, the first of which was from 10 to 14 january, and the last, the latest, haze process, which lasted from 27 to yesterday, the most heavy on 29 january。
Question 1
What's the "smoke" in beijing in january
According to the chief forecaster of the central meteorological service, in the first half of the winter, and particularly before 10 january, our country experienced intense cold air activity, repeated cooling weather events and, even with the fog, a few days later. Since then, circulation has entered the adjustment period and cold air activity has been weak and prone to haze。
In january, chen dae-gang, a senior engineer at the beijing climate centre, described only five days as not haze, the largest in the same period since 1954, in which the real fog days were only two days, only one day more than the annual average, and even more so. In its view, this may be related to the increase in the number of motor vehicles in recent years。
According to wang wings, weather processes and meteorological conditions that are extremely detrimental to the spread of pollutants are objective factors created by widespread ash pollution. In the case of 12 january, the dispersion of pollutants ranged from 200 to 300 metres, 10 times less than usual, leading to the rapid accumulation of local and regional pollutants. This weather process, which originated in winter in the high-latitude stratosphere of the northern hemisphere, has led to an abnormal, very rare, circulation of the atmosphere, “only five times in 30 years”。
Shisho gwang, a professor at the faculty of environment and engineering of beijing university, argued that, although the weather was extreme, the main cause of the haze was high emissions, which could be related to accelerated economic development and increased pollutant emissions since last september。
Question 2
Why do you smell a snort
According to the king's study, in january there was a common denominator in the severe haze days — a strong smell of sulfur dioxide and benzene (smelt of tar) from coal combustion, as well as gas, nitrogen oxides and ammonia from cars, which, moreover, had a stench of corruption. When it's a few mists, the air smells so bad。
Are there more harmful components to human health in these hazes? In response, wang had described the fact that a large number of motor vehicles in beijing would release nitrogen oxides, which would be transformed into nitrates in pm2. 5 particles, and, worse, nitrogen oxides would not only generate inorganic nitrates, but would also generate large quantities of nitrogen-containing organic particles, which would be more harmful to the human body。
In addition, motor vehicle oil and gas volatilizers have been converted into large quantities of organic nitrates or organic meths, which are highly carcinogenic。
Question 3
Why is pm2. 5 increasing at night
During the most recent haze, according to the monitoring data of the city environmental protection agency, the pm2. 5 concentration jumped from two levels to a high level of contamination and serious contamination overnight. The last three pollution processes are also characterized by an increase in pollution overnight。
Wang wings analyses that, normally, the daily sulphur dioxide concentrations in beijing city are not high and have become part of pm2. 5 through complex chemical reactions. In addition to the high levels of sulphate in the daytime of beijing during these pollutions, the high values of sulfur dioxide itself, most of which come from the transmission of coal-fired discharges from surrounding regions, were observed. At night, in addition to the already high sulphuric acid concentrations, more sulphur dioxide was converted to more sulphate than ever before, resulting in a sharp increase in pm2. 5 concentrations。
Ask four
Why does it feel darker this time
Wang wings explained that particles must “bred up” to a certain extent before they become light-scattered, creating a “smoke” that seriously affects visibility. As usual, carbon-containing particles from the local beijing administration do not suck water, so there is no particularly strong haze。
During these periods of ash, the amount of sulphur dioxide and sulphuric acid delivered in the surrounding areas was significant, and these alien particles “suck water”. As a result, a mixture of local “no-smoking” particles and external “smoking” particles also had the effect of absorbing water, “in a general sense, it is fattening.” wang wings said that the result was light-scattering of alien and local particles, which exacerbated the formation of the haze, so that the sky felt darker than ever before。
Question 5
What are the sources of contamination in kyushu
According to preliminary analysis, wang had indicated that in beijing, motor vehicles were the largest source of pm2. 5 in the city, about a quarter, followed by coal combustion and external transport, each accounting for one fifth. In addition, there has been a rapid upward trend in catering in recent years and control should be tightened and industrial and ground dusting should be further improved。
Beijing should focus on the control of cars, since the failure or low-speed movement would result in 5-10 times the emission of motor vehicle pollutants, so vehicle-based tail gas emissions and gas volatilization, as well as the baroque in the catering industry, are the main focus of emergency control of heavy pollution in beijing。
For tianjin, emissions of volatile organic matter are significant because of the advanced oil and gas extraction, transport and processing industries, which affect the air quality of the entire kyinzu region. Therefore, in emergency measures for heavy pollution, priority should be given to controlling volatile organic material emissions represented by petrochemicals。
For hebei, coal combustion is the largest source of pollution and industrial energy production is highly dependent on coal combustion, with nearly 280 million tons of standard coal, with a focus on controlling sulphur dioxide and dust emissions from coal combustion。
Question 6
What's the difference between the london mist
It was described that there had been smoke incidents in london, united kingdom, in 1952, mainly from coal combustion, and in los angeles, united states, in the 1940s and 1950s, mainly from motor vehicle pollution。
Wang wings indicated that these few strong haze pollutants, which have engulfed much of our country in january, are a mixture of pollutants from the london smoke incident and those from the los angeles photochemical smoke incident。
He said that the most dangerous signal during the haze was the detection of large quantities of nitrogen-containing organic particles, which were the main ingredient of the former photochemical smoke in southern california, which was more toxic. In addition to this, the first haze process has been accompanied by a combination of north-west sand and dust, a source that is unique to our country。
In general, these haze processes are a direct consequence of man-made emissions and the destruction of natural ecosystems。
I'm a journalist for this edition
