What are outdoor air pollutants?

Imagine stepping out of your front door and walking into fog that is so thick, you can’t see your feet or the ends of your fingers.  This fog isn’t clean and white, but instead is a dark yellow brown and it contains a strong odor of rotten eggs. No light penetrates this fog and you must shuffle your feet when walking to keep from bumping into objects. Driving is impossible and all outdoor school and sports activities must be canceled. Eventually this fog creeps indoors, making it impossible to continue any indoor events such as concerts or plays. It stays with the city for five whole days before being carried off with the wind. As days pass, the city discovers with horror that there were 4,000 premature deaths directly related to this fog, with many more casualties and deaths to come.

This event was called the London Smog of 1952, which caused massive health related problems for the public. It was one of several incidents worldwide that served as a wake up call on the effects of air quality on health. Eventually, incidents like these led to passing of air quality laws.


So what?

Luckily, we haven’t seen anything of this magnitude in the US, but with wildfires, industrial pollutants, and increased use of motor vehicles, outdoor air quality is becoming a huge concern. However, many of us don’t know much beyond that.


What do I need to know?

There are many air pollutants that exist, but the United States Environmental Protection Agency (EPA) set National Ambient Air Quality Standards (NAAQS) for six major air pollutants:

There are many air pollutants that exist, but the United States Environmental Protection Agency (EPA) set National Ambient Air Quality Standards (NAAQS) for six major air pollutants. Let’s take a look into these pollutants.

  1. Particulate Matter (PM)

Particulate matter is a mixture of different particles in the air that can be solid, liquid, or both. When inhaled it lead to health problems such as asthma.

  1. Ozone (O3)

Ground ozone is a smog like substance that is developed through chemicals reactions of sunlight with other pollutants such as car exhaust, power plant emissions, gasoline vapor, and some natural sources.  


  1. Nitrogen Dioxide (NO2)

Nitrogen dioxide is a gaseous air pollutant that comes from power plants, motor vehicles, and natural sources (volcanoes and lightning). It can contribute to developing ozone.

  1. Carbon Monoxide (CO)

Carbon monoxide is a colorless and odorless gas that comes from the burning of fuels (e.g. automobile exhaust fumes, gas powered lawn mowers/ power tools, charcoal grills, gas appliances, etc.). When breathed in, carbon monoxides prevent us from getting oxygen.

5.Sulfur Dioxides (SO2)

Sulfur dioxide forms from the burning of sulfur containing fuel such as coal, oil, or diesel. It can contribute to fine particle pollution and acid rain.

  1. Lead

Lead gets in the air through the burning of leaded fuels from planes as well as from ore and metal processing. Lead can have harmful effects on our brains and nervous systems. Luckily, lead pollutants in the air have decreased due to the switch to non-leaded fuels.


These are 6 major pollutants that you can keep an eye out for. In the meantime, in order to protect yourself from the major air pollutants:


  • Make sure you know what the air quality is like in your area. You can find this out here. If your score is higher than 100, stay indoors where there is well ventilated and filtered air.

  • For those who have severe allergies and asthma, use this tool before going outdoors to find out the pollen count in your area.

  • If you live in urban or metropolitan areas, give your lungs a break by making regular family trips closer to nature.

  • Conserve as much energy as you can in your home and through your vehicles to reduce the pollutants. Be mindful of the source of fuel that you use (firewood smoke and diesel gas).

If any of you have personal tips, feel free to share in the comments below.

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