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The Smoggy Morning: A Hazardous Time of Day

Air pollution is often associated with the morning haze. However, this notion may not be entirely accurate. So, when is the air quality at its worst, and what can we do to protect ourselves from harmful pollutants?

Administrator

22 July, 2024

Most of us assume that the morning is the most polluted time of day due to the heat, smoke, and emissions from traffic. It is natural to assume that the morning rush hour is the worst time for air quality.

So, we diligently wear our masks when commuting in the morning to protect ourselves from the presumed worst air quality. However, we tend to relax and “open up” in the evenings, believing that the cooler temperatures and reduced traffic result in better air quality than in the mornings.

But here’s the catch—most people are unaware that the air quality in the evenings can be significantly worse than in the mornings. Why is that? According to Quora, the morning sun heats up the Earth, creating air convection currents that expand the air and carry away pollutants.

In contrast, during the evenings, when temperatures drop, a layer of cold air forms near the ground, trapping pollutants and causing them to accumulate. This results in higher pollution levels in the evenings compared to the mornings. Additionally, there is an increase in truck traffic and some factories operate at night, further contributing to the evening pollution spike.

This is further supported by Researchpipeline, which contacted Sparetheair, an organization that maintains air quality monitoring stations around the Bay Area (San Francisco). They found that the highest levels of PM2.5 (fine particulate matter) occur from 8 PM onwards.

But what about in Vietnam? To verify if this trend holds true in Vietnam, we used the Air Visual app, which analyzes air quality data from monitoring stations worldwide, including Vietnam. As expected, the Air Visual pollution charts showed that from 10 PM onwards, the air quality in Ho Chi Minh City deteriorates.

The same pattern was observed in Hanoi, with air quality worsening from 10 PM onwards.

With air pollution becoming an increasingly serious issue, let’s take small but significant steps this year, such as turning off appliances, recycling, and more, to contribute to a healthier environment.

In light of this information, it’s clear that the evenings are not as innocuous as we thought. Therefore, whether it’s morning or evening, it’s important to take precautions to protect your health when outdoors, such as wearing masks properly. Additionally, consider improving your indoor air quality by introducing houseplants, investing in air purifiers, and keeping windows closed to reduce the influx of polluted air.

Frequently asked questions

Smoggy mornings are hazardous due to a combination of factors. The still morning air traps pollutants close to the ground, forming a layer of smog that can be harmful to breathe. Additionally, the morning sun’s rays react with these pollutants, creating a photochemical smog that is even more dangerous.

The morning sun’s ultraviolet rays react with volatile organic compounds (VOCs) and nitrogen oxides (NOx) emitted from vehicles, industries, and households. This reaction results in the formation of ground-level ozone, a major component of photochemical smog.

Inhaling smog can have various adverse effects on health. Short-term exposure can cause irritation to the eyes, nose, and throat, as well as respiratory problems such as coughing and difficulty breathing. Prolonged or repeated exposure to smog may lead to more serious health issues, including lung damage, reduced lung function, and an increased risk of heart and lung diseases.

While anyone can be affected by smog, certain individuals are more vulnerable. This includes children, the elderly, people with pre-existing respiratory or cardiovascular conditions, and those who work or exercise outdoors during smoggy conditions.

To minimize the health risks associated with smog, it is advisable to stay indoors as much as possible during smoggy days, particularly during the morning hours when smog levels are typically at their highest. Keep windows and doors closed, and use air conditioners with recirculated air to reduce indoor air pollution. When outdoors, wear a well-fitting mask rated to filter out particulate matter, such as an N95 or KN95 mask.