Monday, June 24, 2013

Haze Alert! What next?

  Every year, particularly between May to October, Malaysia and Singapore will be plagued by periodic haze from forest fires on Indonesia's Sumatra. This year, the haze which is mainly caused by open burning in Indonesia for land clearing, in addition to other factors like hot and dry weather, have reached hazardous levels in parts of region.

  An increase in air pollutants from 50 to 150 μg/m3 is significantly associated with increases of 12% of upper respiratory tract illness, 19% asthma and 26% nasal inflammation.

Air pollutants

According to United States Environmental Protection Agency (EPA), 6 common air pollutants are being measured in air pollutants. They are particle pollution (often referred to as particulate matter), ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. These pollutants are harmful to health and the environment, and cause property damage. Of the six pollutants, particle pollution and ground-level ozone are the most widespread health threats.

"Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. EPA groups particle pollution into two categories:

Inhalable coarse particles, such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.

Fine particles, such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.

Effects of haze to our health  

Short term effects
Irritated or watery eyes
Runny/stuffy nose
Throat irritation, dry throat, sore throat and/or coughing
Headache, dizziness, fatigue and/or stress
Decrease lung function, difficulty breathing
These symptoms are usually mild and will subside when you stay indoors and limit your exposure to haze.
However, in high risk individuals and those suffering from chronic disease, especially respiratory and heart disease (e.g. coronary artery disease, asthma and chronic obstructive pulmonary disease), their condition may be worsened by haze. They are more likely to develop serious haze-related health effects than healthy people.

Long-term effects
As much as 94% of the particles in a haze are below 2.5micrometers in diameter, that is, particles that are 30 times smaller than the width of a human hair. In view of 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 by animals and humans. The fine particles can also bypass normal body defence mechanisms and penetrate deep into the lungs. When inhaled, they can enter the bloodstream and get absorbed by underlying tissue, potentially interacting with other compounds and substances in the body, for example ‘bad’ cholesterol, to produce damaging effects such as inflammation.

How is Haze Monitored?

Haze is measured by the Pollutants Standards Index (PSI).The PSI is reported as a number on a scale of 0 to 500 and is the air quality indicator. These index figures enable the public to determine whether the air pollution levels in a particular location are good, unhealthy, hazardous or worse. The PSI is used in a number of countries including the United States and Singapore. However, since 1999, the United States EPA has replaced the PSI with the Air Quality Index (AQI) to incorporate new PM2.5 and ozone standards.

In Malaysia, the Air Pollution Index (API) is being used. API is a simple and generalized way to describe the air quality in China, Hong Kong and Malaysia. It is calculated from several sets of air pollution data. The API level is based on the level of 5 atmospheric pollutants, namely sulfur dioxide (SO2),nitrogen dioxide (NO2), suspended particulates (PM10), carbon monoxide (CO), and ozone (O3) measured at the monitoring stations throughout each city.

An individual score is assigned to the level of each pollutant and the final API is the highest of those 5 scores. The pollutants can be measured quite differently. SO2, NO2 and PM10 concentration are measured as average per day. CO and O3 are more harmful and are measured as average per hour. The final API value is calculated per day.

The scale for each pollutant is non-linear, as is the final API score. Thus an API of 100 does not mean twice the pollution of API at 50, nor does it mean twice as harmful. While an API of 50 from day 1 to 182 and API of 100 from day 183 to 365 does provide an annual average of 75, it does not mean the pollution is acceptable even if the benchmark of 100 is deemed safe. This is because the benchmark is a 24 hour target. The annual average must match against the annual target. It is entirely possible to have safe air every day of the year but still fail the annual pollution benchmark.

API and Health Implications (Daily Targets)
APIAir Pollution
Health Implications
0 - 50ExcellentNo health implications
51 -100GoodNo health implications
101-150Slightly PollutedSlight irritations may occur, individuals with breathing or heart problems should reduce outdoor exercise.
151-200Lightly PollutedSlight irritations may occur, individuals with breathing or heart problems should reduce outdoor exercise.
201-250Moderately PollutedHealthy people will be noticeably affected. People with breathing or heart problems will experience reduced endurance in activities. These individuals and elders should remain indoors and restrict activities.
251-300Heavily PollutedHealthy people will be noticeably affected. People with breathing or heart problems will experience reduced endurance in activities. These individuals and elders should remain indoors and restrict activities.
300+Severely PollutedHealthy people will experience reduced endurance in activities. There may be strong irritations and symptoms and may trigger other illnesses. Elders and the sick should remain indoors and avoid exercise. Healthy individuals should avoid out door activities.

How to Protect Yourself from Haze?

Pay attention to local air quality updates. Recommended precautions you should take will usually be given in the form of advisories based on the latest air condition. So it is recommended that you check your local health authority’s website regularly for the latest air quality update. Here are some websites to check for the following countries:

Singapore: National Environment Agency
Malaysia: Department of Environment

Avoid outdoor activities, especially outdoor sports. Children, pregnant women, the elderly, and those suffering from chronic illnesses, especially heart and respiratory disease, should remain indoor when the haze hits unhealthy levels. Healthy adults should avoid unnecessary outdoor activities.

Close all windows, doors and any openings that may allow haze to enter your home and office. Turn on the air conditioner if you have one.

Take your medication regularly if you are suffering from an existing disease, especially heart disease and respiratory disease. If you feel breathless at any point in time, seek medical attention immediately.

Drink more water and increase the intake of fresh fruits and vegetables. They help the body to flush out toxins absorbed through the skin and lungs, and improve the immune system.

Cut down on alcohol and coffee as they promote fluid loss and leach nutrients from the body.

Limit or avoid smoking indoor and the use of gas stove, wood fireplace, candles, incense and anything that burns and emits smoke.

Avoid driving if visibility is bad. If you cannot avoid driving, do not speed and drive at a speed that suits the conditions. Roll up all the windows, turn on the headlight and avoid changing lanes, passing and crossing traffic. Increase your following distance and stay alert.

Under severe haze condition, wear a N95 mask if you must go outside. This mask works better than surgical masks as they seal better and restrict more polluted air from entering the nose and mouth. Besides that, the masks eliminate 95% of particles as small as 0.1 micrometers. It must be tight-fitting. However, it is quite uncomfortable to wear over long periods as extra effort is sometimes needed to inhale. 

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