All around us
Hello everyone! Welcome back to today’s blog post. For the next few posts, the theme would be air pollution! With 91% of the global population being exposed to air quality exceeding WHO guideline limits and causing 7 million deaths in 2012 (WHO, 2014), air pollution is something everyone should be concerned about. Let us learn more about air pollution today!
Types of air pollution
The first thought that comes to mind when talking about air pollution would be poor air quality resulting in poor visibility and foul odours that may result from haze and smog. However, the level of harm caused by air pollution does not correlate well with its visibility! Some air pollutants are so small that they can find themselves deep into your lungs or even enter your bloodstream (EPA, 2019).
Source: https://www.epa.gov/pm-pollution/particulate-matter-pm-basics#PM
Air pollution can also be categorised into indoor and outdoor air pollution. Of the 7 million deaths in 2012 from air pollution, 4 million were attributed to outdoor air pollution while the remaining 3 million were due to indoor air pollution (WHO, 2014). Outdoor air pollution can range from anthropogenic sources such as vehicles and factories running on fossil fuels to slash-and-burn agriculture (WHO, 2018a).
Source: https://www.straitstimes.com/singapore/environment/air-quality-nears-unhealthy-levels-on-friday-marking-the-start-of-a-hazy
Indoor air pollution generally affects populations with less-developed technology, resulting from the use of solid fuels and kerosene for cooking, heating and lighting. With pollutants being emitted from such activities coupled with poor ventilation, these people are chronically exposed to extremely polluted indoor air (WHO, 2018b). However, developed countries may also be affected by indoor air pollution such as second-hand smoke and volatile organic compounds (VOCs) resulting from tobacco smoking and plasticisers (Zhang & Smith, 2003).
Source: “Power supply and the role hydropower plays in sub-Saharan Africa’s modern energy system and socioeconomic wellbeing” (Ebhota, 2019)
Another issue about air pollution is the presence of secondary air pollution. Secondary pollutants are created when chemicals are introduced into the atmosphere. These chemicals are found in many household products that react quickly with the environment to form these air pollutants, adding another layer of complexity to the air pollution problem (Nazaroff & Weschler, 2004). Secondary air pollutants such as ozone (O₃) and sulfuric acid (H₂SO₄) are found to be more harmful due to its reactivity and toxicity, resulting in chemical reactions that produce free radicals and accumulate quickly in an indoor environment (Weschler & Shields, 1997).
To learn more about air pollution, you can head to Jeanice and Zhi Yong’s blog dedicated to air pollution! Their blog discusses air pollution in detail, ranging from anecdotes relevant to Singapore such as the ongoing Hungry Ghost Festival to well-researched tidbits about air pollution in Asia.
Defining air pollution
Given the ubiquitous nature of air pollution, it is essential that its definition is equitable. As such, we will define air pollution as:
“The introduction of contaminant(s) that, through physical, chemical or biological processes, cause(s) or result(s) in deterioration of human health and/or quality of life”
Observant readers may realise that our definition for air pollution is slightly different than that for water pollution. In our next blog post, we shall explain why!
Stay tuned!
Ryan
References
Ebhota, W. S. (2019). Power supply and the role hydropower plays in sub-Saharan Africa’s modern energy system and socioeconomic wellbeing.
EPA. (2019). How Does PM Affect Human Health? EPA. Retrieved from https://www3.epa.gov/region1/airquality/pm-human-health.html#:~:text=Health%20studies%20have%20shown%20a,as%20asthma%20attacks%20and%20bronchitis.
Nazaroff, W. W., & Weschler, C. J. (2004). Cleaning products and air fresheners: exposure to primary and secondary air pollutants. Atmospheric environment, 38(18), 2841-2865.
Weschler, C. J., & Shields, H. C. (1997). Potential reactions among indoor pollutants. Atmospheric environment, 31(21), 3487-3495.
WHO. (2014, 2020). Air Pollution. Health topics. Retrieved from https://www.who.int/health-topics/air-pollution#tab=tab_1
WHO. (2018a). Ambient (outdoor) air pollution. Retrieved from https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health
WHO. (2018b). Household air pollution and health. Retrieved from https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health
Zhang, J., & Smith, K. R. (2003). Indoor air pollution: a global health concern. British medical bulletin, 68(1), 209-225.