27/12/2017
About 50 years ago, Hà Nội was a small and beautiful city with leafy streets, numerous lakes and clean rivers and canals. It has developed rapidly with its area and population about ten times more than before. Increasing industry and construction activities are associated with increasing motor vehicles. As a result, it has suffered from severe air pollution, in particular dust and odor from sewage and polluted ponds, lakes and rivers. This has created negative impact on human health and ecology, and tourism industry.
Air quality is crucial for human socioeconomic development
People can survive for 7 - 10 days without food, 2 - 3 days without water, but only 2 - 3 minutes without air. Air pollution can cause respiratory diseases (nasal infection, sore throat, bronchitis, pneumonia, tuberculosis and asthma), cardiovascular diseases, neurological disorders and skin diseases. Therefore, air pollution is detrimental to human health and can cause economic losses and tourism reduction.
According to a survey by Health Department, Ministry of Transport, in 2011, the total expenditure of respiratory disease diagnosis and treatment, as well as income losses due to illness or having to stay home to look after sick family members is considerable. At present, on average, the cost is 1,538 VND per capita per day in Hà Nội. With the total population of 3 million people, the cost is estimated at about 80.19 million USD per year. A report of General Department of Tourism shows that although tourists are interested in visiting craft villages, they do not want to revisit due to air pollution.
Air Quality Index (AQI) and AQI in some countries
AQT is often used to assess air pollution. AQI is classified into two types: single AQI abbreviated as AQIi to assess individual air pollutants, and AQI 0 to assess the air quality in an area which is an average of the sum of individual AQIi.
Air pollution is divided into five levels: good (AQI = 0 - 50), non-polluted (AQI = 51 - 100), mild polluted (AQI = 101 - 200), severely polluted (AQI = 201 - 300), and extremely polluted (AQI > 300).
At present, the assessment of individual air pollutants is the same in all countries. However, since 2000, the assessment of air pollution for a region or a city has differed. Some countries follow a traditional approach which uses AQI0, the average sum of individual AQIi, to assess the air quality of a region. These countries include Mexico, Europe, Hong Kong, Singapore, Malaysia and India. Some other countries use AQIi of air pollutant with the highest value as the AQI0 to assess air quality of a region. These countries include the US, Canada, China, the UK, Thailand and Việt Nam.
Assessment of air pollution in Hà Nội
Dust air pollution
Results in the period of 2011 - 2015 from some automatic air monitoring stations in urban areas show that PM10 in Hà Nội in 2011 is the highest with a decreasing trend in the following years. This shows some improvement in air quality in Hà Nội.
Hà Nội has the highest AQI in terms of dust, compared with other cities such as Đà Nẵng, Việt Trì, Hạ Long, Huế, Nha Trang. With AQI of dust being 232 (116/50 x 100), the year 2011 is the most polluting, classified as severe polluting. However, in 2015, AQI dust, year is 146 (73/50 x 100) or mild polluting. In these cities, the air in Đà Nẵng is not polluted and cleanest.
Air pollution due to CO, SO2, NO2, O3
Air monitoring results of the period 2012 - 2016 reveal that NO2, SO2 and CO are mainly from vehicles. SO2 also comes from fuel and coal combustion. Therefore, in urban areas, the most air polluted area is roads.
Some big cities such as Hà Nội and Hạ Long have suffered from mild NO2 pollution whereas other medium and small cities are not polluted in terms of NO2 yet.
For SO2 and CO, the monitored values are still lower the permited levels of QCVN 05:2013. However, for CO, the monitored levels are higher that the permited levels in rush hours near transport routes.
O3 is a secondary polluted which is generated from the interaction between air pollutants such as Nox, HC and VOC and unltraviolet. In automatic monitoring stations near main transport routes, O3 concentration is observed to have exceeded the permited level for many days in a year.
Therefore, it can be assessed that the air in Hà Nội has been severely polluted in terms of TPS and PM10. Other air pollutants such as CO, SO2, NO2 and O3 basically have been lower or around the permited levels. According to a study by Yale and Columbia Universities, Hà Nội is in the top ten of most air polluted cities in the world. However, this assessemnt is based on the US Environmental Protection Agency guideline. On 3 March, 2016, the US Embassy in Hà Nội announced that the monitored level of PM5.0 and PM2.5 in the rush hours of 8 -9am was 383 µg/m3. The monitoring results by the Vietnam Environment Administration’s station on Nguyễn Văn Cừ street also showed that the PM10 suddenly rose to around 270 µg/m3 around 8 - 9am on that day. Based on these results, the mass media published that air in Hà Nội was extremely polluted. This is incorrect because the monitored levels were only observed at that time, which could have been caused by a one-off natural interference like a strong wind. The published levels were not the daily average levels (monitored in 24 hours) and hence could not be used as a representative for assessing air pollution in Hà Nội. In practice, to assess the air pollution level of an area for a day, parameters of 24 hour monitoring should be used. Similarly, to assess the annual pollution level, the average level of 365 days (24hours a day) should be used. A parameter monitored at a single certain time could not be used to assess the general pollution level. Even when the level announced by the US Embassy were the daily average level, the daily level estimated would have only been 383µg/m3:150µg/m3 x 100 = 255, which would indicate severe pollution only, not extremely or dangerously polluted like Beijing. The AQI dust of Beijing has been between 300 and 500, which indicates extreme pollution. In those polluting days, the Beijing government had to take measures to reduce the number of vehicles on the roads and suspended some big emitting factories. In the meantime, it recommended that vulnerable people should not go out. In addition, air pollutants in Beijing are more complex than those in Hà Nội. Monitoring results show that about 50% of dust in Hà Nội composes of soil and particulates, and the rest is dangerous black carbon which are generated from fuel combustion. On the contrary, in Beijing, air pollution is mainly due to transport, industry and numerous coal fired heating systems which generates high levels of black carbon. In addition, air pollution in Beijing in terms of SO2 is more severe than in Hà Nội.
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| Air pollution is getting more severe in Hà Nội |
Some measures to restore air quality in Hà Nội
It should be noted that air pollution in Hà Nội is mainly from motor vehicles, big and small scale industrial activities, construction activities, and dust litters from construction material transport. Odour pollution is due to CH4, H2S, NH3 and VOC from open sewage and polluted lakes and rivers.
Therefore, the following urgent measures can be taken:
First, enhancing air environment management capacity in Hà Nội, for example, establishing a division of air environment management, recruit more air environment specialists and conducting training on air enviornment management for staff;
Second, increasing propaganda and guidance on the implementation of regulations on air environment, mobilizing active participation from the public, industries, non-governmental organizations in air environment and environmental protection, increasing self-monitoring activities and counter-pollution activities.
Third, increasing controlling and supervising dust pollution from construction, demolishing activities, road and bridge works.
Fourth, incresing inspection and control of construction material transport vehicles, especially at night time.
Fifth, regularly checking all motor vehicles for their emissions (EURO2, EURO3, EURO4) and banning those who are not in compliance with the national technical regulations.
Sixth, collecting, transporting and treating properly all domestic waste, regularly clean up the streets, watering the streets during dry days.
Seventh, developing public transport means to meet demand, reducing individual motors and cars.
Eighth, applying dust control measures and emission treatment in small and big industries, encourging households and restaurants to switch from coal fired to gas fired stoves ir biomass stoves, cleaning up polluted rivers and lakes, and further developing air monitoring stations, especially automatic ones.
Ninth, planting more trees, protecting and encourging green space in all possible areas (terrances, corridors, walls and roofs)
Air pollution has created negative impact on human health, economic losess and tourism reduction. For sustainable development for the people and the capital city, it is necessary to restore the once clean air of Hà Nội. It is very difficult, but not imppossible with political will and support from community and scientist. Hopefully this would be done in the near future.
Prof Dr. Phạm Ngọc Đăng
Vice President of Vietnam Association for Conservation of Nature and Environment (VACNE)
