Stop The Burning

What is the cause of haze?

Haze is made up of tiny atmospheric pollutants that are mainly the result of human activity in agriculture, such as the burning of crop residue, and industry. When sunlight encounters such pollution particles in the air some light is absorbed by the particles and other light is scattered away before it reaches an observer. More pollutants mean more absorption and scattering of light which reduce the clarity and color of what we see. 

 

What is PM2.5 & PM 10?

As much as 94% of the particles in haze are below 2.5 micrometers in diameter, that is, particles that are 30 times smaller than the width of a human hair. Due to their small size, these ultra-small particles stay in the air longer and are easily carried over long distances, increasing their chances of being inhaled. Known as particulate matter (PM), they are emitted by smoke from post harvest burning, forest fires and other causes of pollution and are toxic and more harmful than particles above PM.2.5. in size. 

 

Thailand sets lower air quality standards than recommended by the World Health Organisation (WHO). Firstly, it adopts PM10 standards (particles of 10 micrometers or less). Secondly, its Pollution Control Department classifies air quality unacceptable if the amount of PM10 in the air exceeds 120 micrograms per cubic metre wheras the WHO sets 50mg per cu m as a PM10 guideline but, nonetheless, encourages all countries to adopt PM2.5 measurements.

 

This disparity makes a big difference in what sets off alarms. 

 

Measurements of PM2.5 – finer particles that can be absorbed into the bloodstream and are considered more dangerous to health than PM 10 - PM2.5 sized particles – are not readily available in Thailand.

 

What are the particles in haze?

Haze is caused by PM from many sources including smoke, road dust, and other particles emitted directly into the atmosphere, as well as PM formed when gaseous pollutants react in the atmosphere. These particles often grow in size as humidity increases, further impairing visibility.

 

Which health symptoms may be related to air pollution?

There are many. Very many. People most susceptible to severe health problems from air pollution are: Individuals with heart disease - such as coronary artery disease or congestive heart failure. Individuals with lung disease - such as asthma, emphysema or chronic obstructive pulmonary disease (COPD). Haze can also cause eye inflammation or conjunctivitis, nasal irritation stimulating mucus production and throat irritation leading to mucus discharge which can clog the respiratory tract. At higher levels of pollution, most people will start to feel breathless and cough.

 

What kind of diseases are caused by air pollution?

• Air pollution exposure can trigger new cases of asthma, exacerbate a pre-existing respiratory illness, and provoke development or progression of chronic illnesses including lung cancer, chronic obstructive pulmonary disease, and emphysema. 

• Living in levels of PM2.5 for 10 or more weeks promotes liver fibrosis, also known as liver scarring, and increases the risk of metabolic disease and liver dysfunction. 

• Long-term exposure to PM2.5 pollutants may induce insulin resistance, inflammation and contribute to the development of diabetes (5, 6). A US epidemiological study found that for every 10 μg/m3 increase of PM2.5, there could be a resulting increase of about 10,000 diagnosed cases of diabetes, or 1% increase in diabetes prevalence. 

• Exposure to polluted air by expecting mothers has also been associated with spontaneous abortion, under-weight infants, birth defects and infant death. 

• A US study published in 2015 found that exposure to air pollution can make the brain age faster. Researchers found that for every 3.49 ug/cm3 increase in cumulative exposure to PM2.5, there is a 6.23 cm3 decrease in white matter. This is equivalent to about 1 ‐ 2 years of brain aging.

 

How is haze monitored?

An air quality index is commonly used to indicate the amount of pollutants in the air over a specified period of time. Each country has its own index that corresponds to a national air quality standard.

 

For instance, air quality in Malaysia & Thailand is reported as the Air Pollutant Index (API) which measures carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and particles that are 10 micrometers or less in width (PM10). 

 

Singapore uses the Pollutant Standards Index (PSI) which includes PM2.5 in addition to PM10, CO, O3, NO2 and SO2. The US & the European Economic Community use only PM2.5 levels. 

 

Continued  on next page: How to avoid breathing haze