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Sunday June 30, 2013

A hazy matter

When circumstances really warrant it, the minimum level of respiratory protection for the haze is the N-95 respirator (mask). When circumstances really warrant it, the minimum level of respiratory protection for the haze is the N-95 respirator (mask).

Are we advocating proper health preventive precautions for the haze?

HAZE is a common phenomenon that occurs during dry spells when smoke particles and dust from forest fires – whether intentionally started to clear land or due to a dry spell – float and migrate across national boundaries.

Dousing off such fires is a challenge due to the thick and vast nature of peat forest.

Haze consists of fine particles that can irritate to the eyes, nostrils, respiratory passage and skin. Sufferers may have symptoms such as runny nose, cough, sore throat or eye and skin irritation.

The symptoms may take about one to three days to appear. They are generally mild for healthy individuals when exposures are short or when the Air Pollution Index (API) is between the moderate level of 51 to 100 and unhealthy level of 101 to 200.

Children, the elderly, patients with lung diseases, heart disease patients as well as heavy smokers are more vulnerable to medical problems when exposed to prolonged haze or haze at very unhealthy API levels between 201 and 300, or at dangerous levels of API between 301 and 500.

Some studies have shown that long term exposure to haze particles may precipitate heart and lung diseases. However, they are unlikely to occur as the presence of haze in this part of the region is for a shorter duration, unlike that seen in the studies where exposure went on for much longer, some to the extent of one year.

People who suffer from eye irritation can easily wash their eyes regularly with clean water or use normal saline drops or natural tear supplements. Use of contact lens should be avoided during this period.

Minimising outdoor exposure or strenuous exercise and consuming sufficient water is advised.

Switch on air conditioners at home where possible instead of leaving windows open.

It is common to see people wearing surgical masks outdoors during the haze. Some even wear it indoors, where it may not be necessary. The US Environmental Protection Agency (EPA) considers particles less than 10 micrometres (PM-10) dangerous when inhaled. In general, particles greater than 10 micrometres are filtered off naturally by the upper airways and seldom cause a problem.

Particles of less than five (PM-5) micrometres are more sinister as they are capable of penetrating deep into the alveoli (lungs). According to the Occupational Safety and Health Administration (OSHA) of the United States Department of Labor, surgical masks are not designed or certified to prevent the inhalation of small airborne contaminants.

These particles are not visible to the naked eye but may still be capable of causing infection.

Surgical masks are not designed to seal tightly against the users’ face. During inhalation, much of the potentially contaminated air can pass through gaps between the face and the surgical mask and not be pulled through the filter material of the mask.

Haze particles are predominantly made up of fine particles that are 2.5 micrometres (PM-2.5) or smaller. Hence, the benefits of face masks are questionable. One may use surgical masks only as a last resort when no better options or alternatives are available.

The minimum level of respiratory protection for the haze is the N-95 respirator (mask). The public should consider using N95 respirators when circumstances really warrant it.

However, you should not stockpile them at homes or workplaces.

These N95 respirators used to prevent the inhalation of haze particles should be able to efficiently filter the smallest particles in this range that will be able to reach the lungs.

According to the National Institute for Occupational Safety and Health in the United States, this product will be able to filter at least 95% of airborne particles. It will be ideal for the public to use the correct and certified disposable respirators.

However, we must be aware of the constraints of wearing them. In view of the numerous challenges and the practicality of using respirators, especially in our hot climate, occupational medicine experts have always advocated the use of personal protective equipment such as respirators as the last resort in their hierarchy of control of hazards.

Respirators have their do’s and don’ts that many are oblivious to. They should be worn properly. They should cover both the nose and mouth completely to prevent the inhalation of particles.

The respirators should be changed frequently when they become soiled or moist with vapour. One should not allow the respirator to hang or dangle around the neck, nor be folded and placed in the pocket for later reuse.

Respirators are items that should not be shared.

Men with beards may not be suitable candidates for respirator use as the seal between the beard and respirator will be compromised and minute particles will be able to go through. As respirators are not made to be used by children, it will not fit them properly.

People who suffer from long term heart or lung diseases, pregnant ladies in the second and third trimester or those with medical conditions that predispose to breathing difficulties should check with their healthcare professionals before using an N95 respirator.

Using an N95 respirator can require more effort to breath. Some models have respirators with exhalation valves. These valves can make breathing out easier and help reduce heat or moisture build-up, especially in our climate.

Employees who are required to work outdoors will have to undergo formal training on how to use N95 respirators. The onus to conduct the training will fall under the responsibility of the employers as they are obliged, under the Occupational Safety and Health Act 1994, to provide a safe and healthy workplace.

OSHA in the United States advises that all respirators should be properly fit-tested using a quantitative or qualitative fit test. In addition to fit-testing, fit-checking procedures should be followed by the user each time the respirator is worn.

This is an important step, especially for employees who are working outdoors for prolonged periods.

It is heartening to note that the Government has made face masks a controlled item under the Price Control and Anti-Profiteering Act 2011 and the Supply Control Act 1961. Under such laws, vendors will be liable for punishment if the masks are sold over the maximum fixed price.

Dr G Jayakumar is an occupational physician with the Perdana University Graduate School Of Medicine, Perdana University.

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