Qualité de l’air à Vientiane

What is the current level of air pollution in Vientiane?

Vientiane is the capital and largest city of Laos, on the banks of the Mekong River near the border with Thailand. According to a census conducted in 2020, Vientiane had an estimated population of approximately 948,477 people.

During the third quarter of 2021, Vientiane was experiencing a period of “Moderate” air quality with a US AQI reading of 58. This United States Air Quality Index figure is calculated by taking note of the recorded levels of six of the most prolific air pollutants. These usually include, both diameters of PM (PM10, PM2.5), nitrogen dioxide, sulphur dioxide, ozone and carbon monoxide. If figures are not available for all six, a level can still be calculated by using what information there is. It can then be used as a metric when comparing one city with another, anywhere in the world. In Vientiane, only PM2.5 was measured which was found to be 15.5 µg/m³. This figure is one and a half times over the target figure of 10 µg/m³ which is set by the World Health Organisation as being an acceptable level, although no amount of air pollution is considered safe.

With pollution at this moderate level, the given advice would be to stay indoors if possible and close doors and windows to prevent the ingress of more polluted air into the rooms. Sensitive groups should avoid venturing outside unless absolutely necessary and then a good quality mask should be worn. There is an app available for download from AirVisual which gives the latest information as to the state of the air.

Is the air quality in Vientiane the same throughout the year?

Looking back at the 2020 figures, published by IQAir.com, it can be seen that the poorest air quality occurred early in the year. In January, February and March, the air quality fell into the “Unhealthy for sensitive groups” category with figures between 35.5 and 55.4 µg/m³. The months of April and May and September until the end of December saw “Moderate” air with figures between 12.1 and 35.4 µg/m³. July returned “Good” quality air with a reading of 11.5 µg/m³ whilst June and August attained the WHO target figure of being less than 10 µg/m³. Their readings being 9.3 and 8.2 µg/m³, respectively.

Historically, records regarding air quality were first kept in 2019 when the annual average was 23.1 µg/m³. The following year showed a slight improvement with a reading of 22.4 µg/m³, but this reading may have been affected by the COVID-19 situation as many vehicles were no longer in daily use as staff were encouraged to work from home in an attempt to halt the spread of the virus. Many factories and non-essential production units were also required to close which removed their emissions from the atmosphere.

Where does the air pollution in Vientiane come from?

The overall situation regarding air quality in the country, including key air quality challenges: particulate matter (PM10) and sulphur dioxide (SO₂) are problem pollutants in Vientiane, although air quality is generally good in the country given the low level of industrialisation and motorisation; mainly an agricultural country (agriculture employs 80 per cent of the labour force), although this is rapidly changing and most industries are small establishments.

Laos doesn’t have a large number of heavy industries and industrial air pollution is managed by the Science Technology and Environment Agency with some monitoring of stack emissions being conducted. Electricity in the country is mainly produced by hydropower.

Outdoor, open burning and open dumping and burning is common practice, together with slash-and-burn agriculture which is very common. The primary source of air quality issues in Laos PDR results from the soil transport, stone, sand, building construction, land development for shelters, construction and road maintenance and dirty roads. Besides this, in some areas, air pollution comes from vehicle exhaust, waste burning, agricultural clearance (rice field, garden), factories (steel, concrete, brick) and construction of shops, garages, and smoke from food processing in houses.

What can be done to improve air quality in Vientiane?

Key transport-related air quality challenges are unpaved roads (only 14 per cent paved); use of 2-stroke vehicles; few public transport vehicles; no emission standards; high sulphur levels.

There is a very low number of public transport vehicles, with buses only available in the capital, and no public bus services in other cities. 3-wheeled tuk-tuks are used instead, although most are 2-stroke which are more polluting than 4-stroke engines and 78 per cent of vehicles are motorcycles. Certain actions which are currently under consideration are the provision of more pavements, more cycle lanes in new road projects and some car-free areas within the city centre. The dominant source of fuel used domestically is biomass which can produce a large quantity of pollutants inside the home.

With an increasing population and the number of vehicles getting more, the traffic conditions in Vientiane are getting worse. The city is experiencing congestion and the related problems of accidents, deteriorating local air quality, and greenhouse gas emissions due to the rapid growth of private motorised vehicles. Following an 11 per cent average annual increase in private vehicles over the last decade, the total number of vehicles registered in Vientiane has doubled over the last five years. With congestion and associated concerns about local air quality, travel times, accidents and a deteriorating urban environment, the rapid increases in private motorised transport are placing Vientiane on an unsustainable transport development path. Currently, public transport within the core area of Vientiane is largely provided by privately operated vehicles, particularly three-wheeled tuk-tuks.

These could be addressed by the introduction of a bus rapid transit (BRT) system, parking and traffic management systems. The development of non-motorised transport (NMT) facilities and a sustainable system for private vehicles.

What effects does this poor air have on human health?

Children, the elderly, people with existing diseases and minority and low-income communities are particularly vulnerable to adverse health outcomes and economic impacts, such as missed work days, from exposure to air pollution.

Research suggests that long term exposure to some pollutants increases the risk of emphysema more than smoking a packet of cigarettes a day. And recent studies show air pollution can impact mental health, worker productivity and even stock market performance.