海防市的空气质量

What are the main causes if air pollution in Haiphong?

Haiphong is the third largest industrial city in Vietnam. Items manufactured here include food processing, light and heavy industries. Cement, iron, pharmaceuticals, textiles and paper are some of the products made here. Heavy industry includes shipbuilding and the manufacture of steel pipes. Hai Phong cement factory is the largest source of pollution within the city. The factory uses outdated equipment which often fails to filter out the dust particles and the toxic gas treatment system often fails completely.

During November PM2.5 levels were found to exceed the permitted threshold in all of Haiphong’s districts. And it was noted that the figure has increased since the previous year.

The difference in temperature from early morning until noon causes air convection to slow down this results in the pollutants becoming trapped in the lower levels and people suffer because of this which is known as the heat inversion phenomenon. This is where heat is conducted from the ground into the air causing fog to form. Specialised agencies often issue warnings for when the air pollution levels rise above predetermined levels. Because of this, many people wear masks when going outside and children are kept at home.

Even though Haiphong is classified as a city, one third of the total area is used for agriculture. As in other cities farmers considerably contribute to air pollution due to the burning of straw and other garbage in order to prepare the land for replanting.

Haiphong has a large fishing industry which uses old boats with inefficient engines. Many of these are the small coracle type boats used by families. The engines on these craft are particularly dirty.

What are the pollutants found in the air in Haiphong?

Records show that the air quality in the craft villages, industrial areas, landfill sites and major road intersections showed significant increases in particulate matter. Harmful gases such as Sulphur Oxide (SO), Sulphur Dioxide (SO2) and Nitrogen Dioxide (NO2) were recorded as were Carbon Monoxide (CO) and Ozone (O3). The recorded levels were between 1.5 to 2.2 times higher than normal.

My Dong craft village, Minh Duc town, Thuy Nguyen district together with the gate area of Vietnam Maritime University showed particularly high levels of pollutants during November.

In 2019 the dust pollution around road intersections reached higher levels when compared to previous years. The presence of the dust is blamed on increased volume of traffic and construction. The production of dust is unavoidable during the construction process, but the contractors are been encouraged to both shield and spray the area with water to prevent dust getting into the air.

The World Health Organisation (WHO) has stated that more than 95 per cent of the world’s population is currently breathing polluted air. They state that environmental pollution is the 4th highest cause of death after high blood pressure, malnutrition and smoking.

What are the levels of pollution in Haiphong?

According to the AQI index in Vietnam, A reading between 100 and 200 is regarded as unsafe. The monitors in Haiphong often record figures of over 150. The Air Quality Index is calculated by using a scale of six AQI ranges. Corresponding to that is the symbol and the colours to warn of the air quality and the degree of possible harm to human health.

Specifically, AQI in the range of 0 - 50 corresponds to good air quality, blue; AQI (51 - 100), medium air quality, yellow; AQI (101 - 150), poor air quality, orange colour; AQI (151 - 200), bad air quality, red colour; AQI (201 - 300), very bad air quality, purple colour; AQI (301 - 500), hazardous air quality, brown.

The air quality parameters used to calculate AQI include: SO2, CO, NO2, O3, PM10 and PM2.5. AQI calculation method requires at least 1 of 2 PM10 and PM2.5 parameters in the calculation formula.

What is the air quality in Haiphong?

The quality of air in Haiphong is currently good with a recorded AQI level of 49. However this figure was only recorded on 37 days so far this year. Unfortunately for 270 days this year, the level has been medium/poor with figures around the 150 mark.

As with most of Vietnam’s large cities, the government is preparing new rules and regulations which will make contractors take responsibility for the emissions caused by their premises. Very often these factories use old equipment which does not work efficiently or is not serviced and cleaned regularly. Consequently the dust and other pollutants get the filters and out into the environment.

Members of the public are increasingly aware of the dangers of breathing polluted air and more and more monitors which are operated by non-government facilities are appearing throughout these large cities and high quality masks are available from the iqair.com website.

How can Haiphong’s air pollution be reduced?

The limitation of vehicles entering the city centre would make a big difference to the air quality in Haiphong. Reducing the PM2.5 levels as well as generally improving the quality of the air. Some of the fuel used by these vehicles is of poor quality and is not governed by any sort of standard. Street vendors sell gasoline from empty glass bottles which is of dubious quality, but it is cheap and therefore popular amongst the less well-off. Being an international port, the amount of traffic found on the road network is growing on an annual basis as Haiphong increases its trade with the world.

With the advent of cheap renewable energy, households could be discouraged from the use of honeycomb charcoal. Currently this is the chosen fuel for most of the city residents. Perhaps solar energy could be utilised in new buildings or maybe even wind energy.

Stringent restrictions are being considered for the manufacturing industry which will make them more responsible for their emissions.

The introduction of an efficient public transportation system would discourage the use of private transport which, at the moment, is ubiquitous.

The introduction of more monitoring stations will give more information as to the overall state of the air quality within the city.