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Chemical Toxicology: What is Affecting us Intangibly

By Mia Dai 

As we all know, we live on Earth, the third planet from the Sun and the only astronomical object known to harbor life, which is also surrounded by a dynamic atmosphere.

What is a dynamic atmosphere? It is a thin layer with its uses of containing the air we breathe. The air we breathe is made of a mixture of particles: 78% nitrogen, 21% oxygen, and 0.9% argon, with the remaining 0.1% consisting of other inactive noble gasses, water vapor, carbon dioxide, and methane, which also comes along with a few aerosols, all of which leave a profound impact on our environment and life (eg. greenhouse effect: sea ice melting, acid rain, etc). Therefore, there are some trace substances in the atmosphere that can have adverse effects on our health, vegetation, climate, and material, which leads them to be known as air pollution. 

Air pollutants categorized themselves into two groups: primary and secondary pollutants, caused by intensive anthropogenic activities from the pre-industrial revolution to the present day. Primary air pollutants are pollutants that are formed and emitted directly from a source. Sulfur compounds such as dimethyl sulfide (DMS) and carbon disulfide (CS2) are primary air pollutants as they are mainly emitted by sea. Secondary air pollutants are pollutants that are not directly emitted from a source, but rather form when primary pollutants react in the atmosphere. For example, ozone (O3), is a secondary pollutant that is formed from the oxidation of volatile organic compounds (VOCs) and carbon monoxide in the presence of nitrogen oxides (NOx) through a combination of chemical mechanisms, and secondary organic aerosols like haze.

This leads us to a question: how do these air pollutants affect our lives? Approximately 30% of the radiation from the sun comes in the form of solar radiation and is reflected by clouds and atmospheric particles as well as by the Earth’s surface. Meanwhile, the remaining 70% of it is absorbed by the atmosphere and Earth’s surface and radiates as heat. A large portion of that energy stays trapped in our atmosphere by greenhouse gasses, which trap excess heat and cause the climate to warm, leading to global warming. According to these projections, the anticipated mean global temperature could rise 1, 1.8, 2.2, and 3.7 degrees Celsius by 2100, which indicates that the Earth’s climate may be more unpredictable with a dramatic change in the frequency of extreme events compared to before. 

Air pollutants can also become an aspect that accounts for human health impact without a trace. Each day a person roughly breathes 12 to 24 kg of air. As a result of this large quantity, even small pollutant concentrations may affect their health. If it is laced with air pollution, the air people breathe may affect the human cardiovascular and respiratory systems, the reproductive and central nervous systems, and could potentially alter the liver, spleen, and blood, depending on the pollutants that are exposed to. Therefore, these air pollutants not only harm the lungs but also have long-term effects on the whole body. In addition, it is considered an aggravating factor in several diseases such as rhinitis, asthma, or even cancer. Indeed, by 2050, outdoor air pollution is projected to become the biggest environmental cause of premature death worldwide, overtaking mass killers such as unclean water and malaria, as the World Health Organization has specified that combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually. 

So, how can we take action to slow down this phenomenon that would take a substantial toll on our planet? First, we can choose low-carbon transportation whenever possible such as public transportation, bike, or walking. Some other options are to reduce anthropogenic activities, limit combustion in the city, plant and care for trees, reduce energy combustion such as natural gas and electricity, and monitor our city’s air quality. 

Every movement we make can help lessen air pollutants’ negative effects on our lives and push toward a better Earth for us to live in. Let’s start now!

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