1/ The warning statistics:

     According to the results from the measurement and analysis of the atmosphere in Hanoi on Oct 5, 2016, it can be seen that the capital of Vietnam was mentioned in the top "extremely unhealthy" air, ranked #2 among the reported cities.

Hanoi's polluted air was once compared to "the atmosphere of the apocalypse day"

     The spot where the action took place that morning was at American Embassy in Hanoi. The AQI (Air Quality Index) was recorded at 245, belonging to the "extremely unhealthy" category. According to the chart of AQI recorded, at the level of 245, citizens were recommended to minimize, even avoid, their going out to protect themselve against health issues.

     Given such figures, Hanoi was the second most polluted city in the world. Its AQI only came after Ardhali Bazar's (a city in India), which was 471, and far outweighed other cities' measured.

     In addition, the statistics for Nhat Tan bridge pier was 187, recognized as "unhealthy". Therefore, exposure to the air was discouraged. The prediction for the next 2 days was that the pollution level would remain at a high level, and it would reach the peak at 10 a.m today morning (Oct 7).

The latest statistics for the real estate of air pollution in Hanoi on Airnow site provided by the Department of Foreign Affairs of the U.S (Note: the figures are constantly updated by real time)

2/ The process of AQI records:

     The statistics are recorded by a monitored machine system at the building of America Embassy on 7 Lang Ha street, Ba Dinh, Hanoi. The figures are organized and pulished by the Agency of Ecosystem Protection of the U.S.

     The Agency stressed that it would be impossible to jump to conclusion about the real estate of the whole city just through this machine system. Hence, these statistics reflects most accurately the situation of the areas around American Embassy in Hanoi.

 The list of the most polluted cities measured

     Prior to this, in a quality report in 2014 provided by the Centre of Environment Observation (the Department of Resources and Environment), it said: "Over the past 5 years, the air quality has not been improved."

     Besides, AQI has always been record at a high level. A typical example was seen in Hanoi in 2013, where there were 237 days of low quality air (AQI ranged from 201 to 300, sometimes it even rose higher than 300, considered "dangerous")

3/ Externalities:

Here is the list of cities recorded as well that morning:

Ardhali Bazar, India: 471

Hanoi, Vietnam: 245

Ulanbataar, Mongolia: 164

Bogota, Colombia: 158

Ankara, Portugal: 157

Beijing, China: 152

Singapore: 137

Jerusalem, Isreal: 112

Useful Information

The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The AQIfocuses on health effects you may experience within a few hours or days after breathing polluted air.

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