Qualité de l’air à Son Tay

What is the air quality index of Sơn Tây?

Sơn Tây is a district-level town that has been “absorbed” by Hanoi, the Vietnamese capital. It is a mere 35 kilometres to the west. It is also fondly known as “Soldier Town” due to a large number of military training facilities there. It is thought that in the future some public facilities and universities will relocate here as it is thought of as part of Hanoi but the land is much cheaper than in the capital itself.

At the beginning of 2021. Sơn Tây was experiencing poor quality air with a US AQI reading of 177. This classified it as “Unhealthy” according to the recommended figures by the World Health Organisation (WHO). The level of PM2.5 was recorded as 105.3 µg/m³ which is indeed high.

With conditions such as these, it is advisable to close windows and doors to prevent the ingress of dirty air and run an air purifier if one is available. All forms of outdoor exercise should be avoided until the air quality improves.

What is the main source of Sơn Tây’s polluted air?

The main causes of air pollution in Hanoi and Son Tay were dust, emissions from vehicles, and construction activities. Industrial activities with a large amount of waste which is not yet effectively controlled combined with adverse weather factors in the seasonal period.

Vietnam currently has 3.6 million cars and 58 million motorbikes which are mainly concentrated in big cities. Many of them are old vehicles with poor emissions control technology. Vehicles cause daily traffic jams, and at the same time emit large amounts of pollutants. Many old buses and motorbikes emit black smoke due to a lack of emission controls.

Contrary to the belief of many people, traffic is not always the main source of air pollution, its level of contribution varies considerably, from 10-50 per cent depending on the period. Waste gas from residential cooking with coal or wood stoves may account for 15-20 per cent; while activities associated with agriculture, including burning of biomass straw and other dried vegetation and ammonia emissions in livestock and fertilisers contribute about 7-22 per cent.

Does air pollution in Sơn Tây differ throughout the year?

During the colder months of November, December and January, the quality of air is at its worst with PM2.5 levels between 55.5 and 150.4 µg/m³. July and August bring the cleanest air but even then it is still classified as “Moderate” with figures between 12.1 and 35.4 µg/m³. For the remaining months of the year, the quality is “Unhealthy for sensitive groups” with figures between 35.5 and 55.4 µg/m³. There have been no signs of improvement over the last few years. In 2017 the figure was 45.8 µg/m³, in 2018 it was 40.8 µg/m³ and in 2019 it was 46.9 µg/m³.

Scientists found a rule: summer (May-September) in Hanoi usually has a much lower level of particle pollution than winter (October-January). Heat inversions, especially in winter, cause pollution at night to be about twice as high than during the day.

During the dry season, heavy pollution usually starts a few days after the northeast monsoon starts and lasts for many days until the prevailing wind turns to the Southeast before a new monsoon occurs.

What can be done to improve the air quality in Sơn Tây?

Since August 2018, Hanoi has put into operation a number of bus routes using CNG clean fuel.

Regarding traffic emissions, the results of a recent study have been published regarding fuel conversion for buses and taxis in Hanoi. Accordingly, if a diesel-powered bus changes to a cleaner fuel such as CNG compressed natural gas or liquid propane gas LPG, the emission factor of Hanoi buses can be reduced by 30-100 per cent, depending on the scenario.

Similarly, with taxis, if you switch from gasoline to CNG or LPG fuel, and raise the emission standard to Euro 3 or Euro 4, the taxi's emission factor can decrease from 40 -100 per cent depending on the situation.

Currently, the honeycomb charcoal stove is banned because it is a low-grade stove and creates high levels of carbon monoxide (CO) emissions; limiting the burning of straw which causes a lot of environmental pollution; all construction work and cement producers that generate dust must be shielded and watered; upgrade standards and regulations for means of transportation.

It has been noted that if Europe is applying EURO 5 and EURO 6 standards for vehicle emissions, at least Vietnam should apply EURO 4 at the very least, to improve air quality. That is why Hanoi and Son Tay have to make a decision to reduce private vehicles and increase the use of public transport. When they are all vehicles that meet the clean fuel standards, there is no emission problem.

What are the effects of breathing Sơn Tây’s poor quality air?

Fine dust such as PM2.5 is especially harmful to human health because they have the ability to penetrate deeply into the lungs and cardiovascular system, causing many diseases such as stroke, cardiovascular disease, lung cancer, chronic obstructive pulmonary disease and other related respiratory infections. The World Health Organisation (WHO) estimates indicate that there were 60,000 air pollution-related deaths in Vietnam in 2016.

During times of bad air quality and a high pollution index, the frequency of patients hospitalised due to cardiovascular and respiratory causes is noticeably higher than at other times. The first and most obvious affected people are those with pre-existing cardiovascular and respiratory problems. Patients find it difficult to breathe, have more coughs, chest pains and are more prone to increased asthma attacks.

The people most affected by air pollution include children, women and outdoor workers. Pneumonia is the leading cause of death in children under five years of age, where air pollution is a major risk factor. Women working in smoky kitchens have the highest household pollutant levels. For outdoor workers such as traffic workers and street vendors, they are the most affected by outdoor pollution.

The medical term for shortness of breath is dyspnoea is a term used to describe discomfort or difficulty breathing.

Shortness of breath is not always a symptom of a health problem; it can result from overwork going up to a higher altitude or temperature amplitude suddenly, or it is caused by poor quality air. However, when breathing is severe and prolonged it can be a warning of respiratory system problems or disease in other organs of the body.