Air quality in Nakhon Si Thammarat

How polluted is the air in Nakhon Si Thammarat?

Urbanization results in the increase in traffic density which is in turn is a major cause of air quality deterioration. For the past decade, the number of newly registered vehicles in Thailand has increased threefold when compared with the figures for 2011 with levels of air pollutants occasionally exceeding the national ambient air quality standards (NAAQS). Various measures toward better air quality have been implemented in the country, particularly Bangkok to combat air pollution problems. The overall situation has improved; however, a problem related to the particular pollutants, i.e. particulate matter PM2.5, PM10 and ozone (O₃) remain. Nakhon Si Thammarat is, in terms of population, the biggest province in Southern Thailand and ranks in the top ten of the country according to the 2011 records. Here too, the number of newly registered vehicles has increased by 350 per cent over the past decade.

The lack of permanent monitoring stations in the city gives cause for concern as to the validity of quoted figures. It was decided to monitor the air quality in Nakhon Si Thammarat, over a period of four consecutive days at three main road intersections: Tha Wang; Ku Khwang; and Lak Muang. The results revealed that for the period of three hours the average PM10 concentrations ranged from around 60 to 140 μg/m³ and 40 to 170 μg/m³, respectively in the morning and evening while those for PM2.5 ranged from 40 to 110 μg/m³ and 40 to 160 μg/m³, respectively. These concentrations exceeded the World Health Organisation’s (WHO) recommended levels thus prompting the implementation of tighter controls to help mitigate the circumstances. It is also suggested that other factors are taken into consideration such as the volume of traffic, the engine type most commonly used as well as the type of fuel used. It is hoped that these figures will indicate a connection between traffic density and air quality.

Due to the lack of a ground-level monitoring station, the figures published by IQAir.com are based on satellite data. In early December 2020 figures ranged from 27 US AQI which is classed as “good” to 90 US AQI which falls into the “moderate” category, whilst PM2.5 figures hovered around the 10.0 µg/m³ mark.

What is the cause of air pollution in Nakhon Si Thammarat?

Some of the air pollution in Nakhon Si Thammarat comes from forest fires. In August 2019 there was a particularly fierce fire in the swamp area surrounding the city. This caused the levels of PM2.5 to rise alarmingly. Nakhon Si Thammarat recorded a level of 86 µg/m³ with an acceptable level being 50 µg/m³ or lower, as suggested by the World Health Organisation (WHO). Using satellite images, over 50 “heat spots” were discovered and recorded levels of dust particles were measured at being over 80 µg/m³ for a consecutive period of 24 hours. It was announced that if anybody was experiencing breathing difficulties or tightness in the chest that they should seek advice from the Khao Phrabat hospital.

Another major contributor to the poor air quality in Nakhon Si Thammarat is the stone crushing plant. In 2017 a study was instigated to record the concentrations of particulate matter smaller than 10 micrometres and to assess the risk of exposure to dust particles smaller than 10 micrometres in the communities near the stone mill. Because Nakhon Si Thammarat has no ground station monitor to record the level of air quality within the province, data from the results of this study is only a way to monitor problems.

Other factors which contribute to the poor air quality is the open burning of agricultural by-products after the rice harvest and the volume of traffic using the roads. Often these are older vehicles and therefore do not meet current standards/recommendations with their emissions. Very often the fuel used in motorbikes has been adulterated by the addition of cheap hydrocarbons, thus adding to the lethal cocktail of pollutant gases.

What can be done to reduce the level of air pollution in Nakhon Si Thammarat?

One of the main sources of air pollution in Nakhon Si Thammarat is dust created by the stone crushing plant. It has been suggested that a more effective filtration system should be introduced to capture the dust before it contaminates the environment.

The use of public transport is to be encouraged as an attempt to reduce the number of private cars and motorcycles using the road.

Due to the high level of pollution caused by crop burning, the cessation of this practice would make a huge difference. However, the alternatives are more complicated and often cost money so are not popular with the farmers.

What are the effects on health caused by polluted air in Nakhon Si Thammarat?

Healthy people can experience health problems through breathing in polluted air. It is more noticeable whilst taking exercise or other outdoor activities. Very often, the effects are directly related to your present state of health. Some of these problems may include aggravated cardiovascular and respiratory illnesses and increased stress to the lungs and heart because they have to work harder to get the oxygen they need. Cell damage in the respiratory tracts can also occur. Prolonged exposure accelerates the ageing of the lungs leading to loss of lung capacity and decreased function. The body is at greater risk to illnesses such as asthma, bronchitis, emphysema, and possibly cancer.

The groups of people more susceptible to respiratory problems are those with existing medical conditions, pregnant women, outdoor workers, seniors and children under the age of 14 years.

Exposure to Particulate Matter (both PM2.5 and PM10) is detrimental to health. This pollutant can be very complex and contain a myriad of substances, such as soot, tyre rubber, metals, nitrates, sulphates, dust particles and water. Because of the microscopic size of these particulates, they can travel deep unto the lung tissue as far as the alveoli which are found at the base of the bronchial tubes. From here they can enter the bloodstream and eventually reach the heart.