Traffic builds up near the Guadalupe Bridge along EDSA on June 5, 2024 following to a sudden downpour in the metro. Jonathan Cellona, ABS-CBN News/file

MANILA -- Researchers from the National Institutes of Health (NIH) at the University of the Philippines Manila (UPM) have found a "significant correlation between occupational noise exposure and hearing problems" among personnel of the Metropolitan Manila Development Authority (MMDA) working along EDSA, one of Metro Manila's major and busiest roads.

The study revealed that "EDSA traffic enforcers who were exposed to an 8-hour equivalent sound pressure level of more than 85 decibels A were at least 25% more likely to experience hearing abnormalities especially at frequencies above 2000 Hz."

"Our study showed that 13% of the research participants experienced significant noise exposure at work, and approximately 16% of the participants had moderate hearing loss or worse on at least one ear," said Dr. Kimberly Mae C. Ong, Research Assistant Professor at the Philippine National Ear Institute (PNEI) in an article published by the UP Manila website.

According to Ong, a "surprising finding" was that "none of the field personnel had proper equipment to protect themselves against harmful noise exposure".

"Some of them felt that their bandana provided them sufficient protection from noise. This showed us that there is a need for hearing health education, which we hope can be integrated in their training," she explained.

"At work, these subtle changes in hearing can affect an employee’s ability to communicate effectively with their co-workers, possibly leading to misunderstandings. It can affect productivity and work efficiency, so there is also a potential economic impact. Significant chronic noise exposure often causes irreversible hearing loss; thus, the focus should really be on hearing loss prevention," she added.

NOISE EXPOSURE

According to the UP Manila article, the study wants to show "the importance of regular noise exposure monitoring for traffic enforcers and identifying high-risk areas for targeted noise mitigation".

The findings also pose "broader implications for other occupations exposed to road traffic noise, such as street sweepers, vendors, and public transportation drivers".

"I hope this research helps to create awareness about the possible effects of prolonged noise exposure, especially to road traffic noise," Dr. Ong was quoted as saying.

The study by the team of researchers was conducted "in close coordination with the MMDA", including 108 employees assigned along EDSA, "with more than five years in their current positions, comprising both field and office-based personnel."

"Each employee wore a noise dosimeter to record noise levels during their 8-hour work shifts. Hearing tests were conducted at least 16 hours after work to avoid the effects of a hearing phenomenon known as temporary threshold shift," the article explained.

The World Health Organization (WHO) defines noise as an "underestimated threat" that may cause health problems, including "sleep disturbance, cardiovascular effects, poorer work and school performance, hearing impairment, etc."

"The WHO guidelines for community noise recommend less than 30 A-weighted decibels (dB(A)) in bedrooms during the night for a sleep of good quality and less than 35 dB(A) in classrooms to allow good teaching and learning conditions," the agency said.

"The WHO guidelines for night noise recommend less than 40 dB(A) of annual average (Lnight) outside of bedrooms to prevent adverse health effects from night noise," it added.

Meantime, the WHO estimates that by 2050, "nearly 2.5 billion people are projected to have some degree of hearing loss, and at least 700 million will require hearing rehabilitation".

"Over 5% of the world’s population – or 430 million people – require rehabilitation to address their disabling hearing loss (including 34 million children). It is estimated that by 2050 over 700 million people – or 1 in every 10 people – will have disabling hearing loss," it explained.

"Disabling hearing loss refers to hearing loss greater than 35 decibels (dB) in the better hearing ear. Nearly 80% of people with disabling hearing loss live in low- and middle-income countries. The prevalence of hearing loss increases with age, among those older than 60 years, over 25% are affected by disabling hearing loss," it added.

According to the agency, hearing loss may be mild, moderate, severe, or profound. The condition can affect one ear or both ears, leading to difficulty in hearing conversational speech or loud sounds.

WORKING ON RECOMMENDATIONS

MMDA Acting Chairperson Romando Artes acknowledged two "major concerns" for their enforcers in the streets: the effects of smoke coming from vehicles to the respiratory system and that of hearing loss.

He shared that they are studying recommendations that can help control possible hearing loss among MMDA personnel.

"Amin po pinag-aaralan kung anong magandang rekomendasyon. Hindi naman po pwedeng completely magkaroon ng ear plugs iyong aming mga enforcers para hindi maapektuhan [ang pandinig] dahil delikado rin iyan sa kanila – hindi nila maririnig kung may parating na sasakyan. Amin po pinag-aaralan kung anong pwedeng gawin para ma-mitigate or mabawasan iyong masamang epekto ng tunog ng sasakyan at mga busina doon sa pandinig ng ating enforcers," he said.