December 2, 2020

How Clean Air Slows the Spread of Airborne Infectious Diseases

Since early 2020, our understanding of COVID-19 has grown exponentially. Out of these changes, an important development has been scientists’ perspective on how COVID-19 is transmitted and how to combat and slow the spread effectively. Wash your hands, sanitize surfaces… that’s how we’re taught to fight most diseases. But we know now that a lack of hand hygiene isn’t the main way COVID-19 spreads. In fact, now we know that COVID-19 spreads in two primary ways: through short and long-range transmission of airborne particles.

However, scientific research on airborne diseases, such as whooping cough or measles, is less than a century old. Dr. Shelly Miller, an environmental engineer from Boulder, Colorado, recently shared a useful video discussing how respiratory infectious diseases spread between people.

What is short-range airborne transmission?

Short-range transmission occurs when an infected person stands between eight inches and six feet of someone else. When a person coughs, speaks, yells, sings, or sneezes, they emit droplets. These respiratory droplets are sometimes visible, such as when you sneeze.

Often, these droplets aren’t visible. This happens when you speak, for instance. Coronavirus particles tend to attach to these droplets. At point-blank range, these droplets land on someone else’s eyes, nose, or mouth. This is especially true when it comes to two unmasked people.

Primary methods of controlling short-range transmission include masking, quarantining after exposure, and social distancing. Limiting the number of people in a given room is also important.

  • Masking means that you limit both the number of virus-containing particles you inhale and exhale.
  • Quarantining prevents you from shedding virus and transmitting it to others.
  • Social distancing eliminates the potential for short-range transmission.
  • Occupancy restrictions limit the chance of infection spread because fewer people are in the room.

However, even following all of these protocols, we still have long-range transmission to deal with.

What is long-range airborne transmission?

Long-range transmission occurs when you inhale virus-containing particles floating in the air. As discussed above, aerosolized droplets produce when you yell, cough, speak, sing, or talk. When you sneeze, for instance, droplets don’t disappear. Instead, they attach themselves to larger particles of dust or liquid and have the possibility to remain suspended in the air for some time. Air currents, movements, doors opening, and closing–all of these factors can spread floating particles for incredible distances.

Once someone inhales enough infected aerosolized droplets, they become infected. With no set number count of what ‘enough’ looks like, removing as many particles as possible from the air before they are inhaled into someone’s respiratory tract is crucial. The old saying, “An ounce of prevention is worth a pound of cure,” rings true when it comes to ventilation.

Slow the spread, ventilate your way out

Dr. Miller says: “you can’t ventilate your way out of short-range transmission, but you can ventilate your way out of long-range (aerosolized particle-driven) transmission.”

If you’re standing eight inches from someone’s face, a ventilation system won’t help you. The most powerful system in the world won’t be able to eliminate risk. Masks and social distancing are critical here. However, when it comes to long-range transmission–which means infected particles are suspended in the air and actively circulating–that is a problem you can ventilate your way out of.

Your building’s HVAC system might not cut it, though. Often, they recirculate air–that might be infected–that is trapped inside a building. Most modern buildings are tightly sealed to prevent temperature fluctuations, too. Great for energy efficiency, but unhelpful when fresh, clean air is needed. The best solution involves high-quality filtration and a high number of air changes per hour (ACH).

Omni CleanAir portable air purification systems combine portability with three proven technologies to eradicate pathogens and pollutants from indoor air. True HEPA filters can remove particles that are 0.3microns or less. This type of filtration, which has been used in low-level nuclear cleanup, must be paired with a high number of ACH. In construction zones, for instance, the standard is the entire volume of air being changed 6 times per hour. This is a bare minimum for indoor spaces and should be increased nearer to the hospital standard of 12 ACH when possible.

By increasing ventilation rates through True HEPA filtration, you can increase peace of mind for yourself, customers, and staff.