Air Quality Index, What’s In Wildfire Smoke, and the Use Of Respirators.

In order to help you make sense of current circumstances, this quick article will provide a quick explanation of the Air Quality Index, what contaminants exist in fire smoke, and what cost-effective solutions are available to the average consumer to help keep themselves safe during such events.

AQI: What is it?

Each country's health authorities provide some measure of air quality indicator to the general public. In the United States, the so-called AQI is an index measuring the levels of five major pollutants relative to permissible levels established by the Clean Air Act. Those pollutants are:

• ground-level ozone
• particulate matter (fine particles - 2.5 microns / coarse particles - 10 microns)
• carbon monoxide
• sulfur dioxide
• nitrogen dioxide

The index is reported on a range of 0 to 500, with levels of 101 or higher considered unhealthy for those with respiratory or health conditions, 151 or higher considered unhealthy for everyone, and 301 and higher being outright hazardous for anybody who is exposed. Conversely, 100 or below is considered normal air quality for all these pollutants, as some level of harmful chemicals are always present in the air we breathe, especially if you live in suburban or urban areas. If you've ever stood next to a smoky campfire, you've experienced an AQI of 151.

While the AQI is helpful at a high level and should be paid attention to, it is important to understand that each of the pollutants it measures impact people differently. Here's an explanation of each so you can determine which of these harmful pollutants is of particular concern to you:

• Ozone - unhealthy AQI starts at .071 PPM (parts-per-million) avg. over an 8 hour period - people with lung disease or conditions like asthma, children, pregnant women, older adults, and those who are active outdoors (including in professional activities like contractors), and those who are considered medically overweight or obese
• Particulate Matter (PM 2.5 / PM10) - unhealthy AQI starts at 35.5 PPM avg. over an 8 hour period - People with heart or lung disease or conditions like asthma, pregnant women, older adults, and children, and those who are considered medically overweight or obese
• Carbon Monoxide - unhealthy AQI starts at 9.5 PPM avg. over an 8 hour period - people with heart disease is the group most at risk
• Sulfur Dioxide - unhealthy AQI starts at 76 PPB (parts-per-billion) avg. over an 1 hour period - people with asthma, children, and older adults are the groups most at risk
• Nitrogen Dioxide - unhealthy AQI starts at 101 PPB avg. over an 1 hour period - people with asthma, children, and older adults are the groups most at risk

To explain some of the units referenced above, PPB is parts per billion and ppm is parts per million. Each represents a ratio of the number of pollutant molecules per one million air molecules. Measurement volumes vary for each kind of contaminant, with PPM and PPB being measured across a 1 liter volume, and particulate matter being measured across a 1 meter cubed volume. The AQI we see reported on the news and in our weather apps is based on an aggregate data set of thousands of sampling sites in a given area and is generally more accurate for sites that are closer to urban centers.

Which of the listed AQI contaminants are contained in smoke?

All of them, simply put. Fire smoke, particularly wildfire smoke, contains a mix of hazardous gases, particulate contamination, and water vapor. Of principal concern to humans and animals are gaseous and particulate matter contaminants released, which can include a wide range of inorganic, organic, dust, and biological particles such as those measured by the AQI, but also elements from structures and other man-made items caught in the blaze. Cars, buildings, and other infrastructure burn due to the intense heat of wildfires and as a result trace amounts of lead, manganese, hydrogen fluoride, and dangerous chemicals are also present. Scientists refer to these contaminants as "HAPs" (Hazardous Air Pollutants) and they form as the result of incomplete combustion, meaning the fire's fuel source doesn't fully complete the transition into CO2.

Most HAPs are covered within the Particulate contamination levels measured by the AQI. There are two types of particulate matter measured; those greater than 10 microns cannot enter your bloodstream by way of the lungs, particles of 2.5 microns and below can enter your bloodstream via the lungs when inhaled. That is why those with heart disease and those who are pregnant or nursing are listed as being specifically at risk even though it feels like the circulatory system is far removed from risks to your pulmonary system. Contaminants can cross into the bloodstream via your lungs. Also, for obvious reasons, those with asthma and lung disease are also at risk because of the reduced levels of oxygen present in contaminated air.



What solutions are available to me?

Most public health agencies recommend an N95, like our Gerson N95 masks, for protecting yourself from the toxins and contaminants found in smoke-filled air. As we have said here many times, while N95s are better than nothing they an imperfect solution as the efficacy of such masks relies on wearing them properly and in accordance with manufacturer guidelines following a proper fit test. This means the wearer must be clean-shaven and the mask must be properly fitted over their nose and mouth, and may need to size up or size down the mask depending on their face shape. When worn properly, they are a low-cost and highly available way to keep yourself safe from limited exposure to airborne contaminants like wildfire smoke.

For those with particular breathing difficulties caused by pre-existing lung disease, birth defects, allergies, beards that prevent an N95 from being worn properly, or those that N95 masks simply don't fit, the only option is to create a positive pressure zone around their nose and mouth by way of a PAPR or power-assisted respirator. Wearing a PAPR also comes with the additional benefit of preventing coarse particulate contamination from entering the body by way of the eyes / tear ducts. 

We have a curated selection of passive and positive pressure respirators here that are suitable for cleanup and recover efforts following a wildfire. 

We hope that you've found the above information helpful. If you are visiting our site from California following the LA wildfires we wish you, those you know, and your broader communities a swift recovery. Should you have any questions about the best solution for your needs, please don't hesitate to reach out.

Stay safe out there.