The Pollutant Standards Index (PSI) measures the air quality and indicates the severity of haze. A PSI reading of 101 and above is deemed unhealthy. MOH will issue haze health advisories based on the 24-hour PSI when the daily average of PSI levels over a few days is deemed unhealthy.
The health impact of haze is dependent on one’s health status (e.g. whether one has pre-existing chronic heart or lung disease), the PSI level, and the duration and intensity of outdoor activity.
For healthy individuals, short-term exposure (i.e. over a few days) to haze will generally not cause any major health issues, other than irritation of the eyes, nose, and throat. N95 masks are not needed for such short-term exposure, like commuting from home to school or work. N95 masks are also not needed in an indoor environment.
In most cases, it is still safe to carry on with outdoor activities. However, you should drink plenty of water to stay hydrated, and individuals with existing chronic heart and lung conditions should ensure that medications are on hand and readily available.
Reducing outdoor activities and physical exertion can help limit the ill effects from haze exposure. Healthy individuals who need to be outdoors for several hours when the air quality is in the hazardous range (PSI >300) may reduce exposure by wearing an N95 mask with a good fit. Elderly, pregnant women and people with severe lung or heart problems should consult their doctor as to whether they should use the N95 mask if they have to be outdoors for several hours.
While this health advisory provides general precautionary advice, each individual’s reaction to pollutants may vary. The amount of physical activity or exertion that can be performed outdoors during haze periods also differs according to an individual’s health status or capacity. Persons who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical advice.
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