Qualité de l’air à Phrae

What is the level of air pollution in Phrae now?

Phrae is a town in northern Thailand and is the capital of Phrae Province. It is approximately 555 kilometres north of Bangkok. A 2005 census estimated the population to be approximately 18,000 people. It is situated on the east bank of the Yom River although some development is now taking place on the opposite bank which is connected to the main area by bridges.

Towards the middle of 2021, Phrae was experiencing a period of “Moderate” quality air with a US AQI reading of 62. This United States Air Quality Index figure is an internationally used set of metrics that is used to determine the level of air pollution at any given time. It can be used to compare several cities, even when they are in different countries. The number is calculated by measuring up to six of the commonly found pollutants in the air. Sometimes records are not available for all six so the calculations are made using what data is available. In the case of Phrae, only PM2.5 was measured which stood at 17 µg/m³.

With levels such as these, the advice is to close doors and windows to prevent more dirty air from entering the room. Those of a sensitive disposition are advised to remain indoors or if travel outside is unavoidable, then a good quality mask is recommended. The table at the top of this page will help with that decision.

Is the level of air pollution constant throughout the year in Phrae?

Air quality can be affected by many variables such as the season of the year, wind speed and direction and the strength of sunlight so it can change very quickly depending on local conditions.

Figures have now been released by the Swiss company, IQAir.com for 2020. For the two months of the year during June and August, Phrae attained the target figure as suggested by the World Health Organisation (WHO) of less than 10 µg/m³. For July, September and October the classification was “Good” with figures between 10 and 12 µg/m³. May, November and December saw a decline in quality when it slipped into the “Unhealthy for sensitive groups” category with figures between 35.5 and 55.4 µg/m³. The remaining three months of the year for January, February and March saw the worst quality air for Phrae when it was classed as being “Unhealthy” with readings between 55.5 and 150.4 µg/m³.

Historically, records have been kept from 2019 when the annual average figure was 31.3 µg/m³ followed by 29.5 µg/m³ in the following year, 2020. This may not be a truly accurate reading because of the restrictions imposed due to the COVID-19 pandemic. Many vehicles were no longer used as the drivers were furloughed not required to commute on a daily basis. There were also many factories and other non-essential production units which were temporarily closed in an attempt to prevent the spread of the virus.

What is the main source of air pollution in Phrae?

In 2002, Bangkok and the rest of the central region contributed between 60 and 70 per cent of the country's industrial emissions. Most power plants rely on burning fossil fuels. Other sources of air pollution include garbage burning, open cooking, and agricultural burning practices, including deliberate forest fires.

In February 2016, the haze affecting northern Thailand has reached levels that can be considered as being very harmful to health. Reports stated that the levels of particulates measuring less than 10 micrometres—known as PM10—had crossed the prescribed safe threshold of 120 in four out of nine provinces where monitoring was conducted. The level of PM10 in the nine regions—Chiang Rai, Chiang Mai, Lampang, Lamphun, Mae Hong Son, Nan, Phrae, Phayao and Tak—was measured at between 68 and 160. The haze level was considered unhealthy in Chiang Mai, Lampang, Lamphun, and Phrae Provinces.

Large, multi-national corporations in the agricultural sector, not farmers, are the biggest contributors to smoke pollution. The main source of the fires which are in forested areas are being cleared to make room for new crops. The new crop to be planted is maize. A chart of Thailand's growth in the world corn markets can be overlaid on a chart of the number of fires. The two are seen to be inextricably linked.

Can anything be done to improve the air quality in Phrae?

Farmers who currently grow maize are being encouraged to switch to cash-crops such as coffee which uses less land than maize and is more profitable. The main drawback is that coffee can take up to four years before the first harvest, however the group behind the initiative has said they will support the farmers until their first crop is sold.

What detrimental effects on human health does the air in Phrae have?

Even healthy people can experience detrimental health impacts from polluted air including respiratory irritation or breathing difficulties during exercise or outdoor activities. The actual risk of adverse effects depends on your current health status, the pollutant type and concentration, and the length of exposure to the polluted air.

Air pollution has a disastrous effect on children. Worldwide, up to 14 per cent of children aged 5 – 18 years have asthma exacerbated by air pollution. Every year, 543 000 children younger than 5 years die of respiratory disease linked to air pollution. Air pollution is also linked to childhood cancers. For pregnant women who are exposed to air pollution, it can affect foetal brain growth. Air pollution is also linked to cognitive impairment in both children and adults.

Ground-level ozone reaches its highest level during the afternoon when the sunlight is at its strongest. High levels occur most often during the summer months. It is a strong irritant that can cause constriction of the airways, forcing the respiratory system to work harder in order to provide oxygen. It causes an effect similar to sunburn.

It also causes aggravated respiratory diseases such as emphysema, bronchitis and asthma. Less dangerous but equally problematic are wheezing, chest pain, dry throat, headache or nausea. It can also reduce the body’s resistance to infection from other sources, as well as an increased feeling of fatigue.