Avoiding Viruses

I was at a meeting here in Oakland the other day, one of those wonderful meetings about projects we have around here. There was food – good food, too, not just the usual pizza – and people who had critical things to say were careful in their phrasing.

(As a person who has developed a hatred of meetings after a lifetime of going to them, I am often pleasantly surprised by how good our meetings are in Oakland.)

But there was one thing: I had brought a CO2 meter, because I knew we would be meeting in a basement room, and over the course of the meeting it began to register not just high, but seriously high. I put on a mask, but finally decided to say something.

People were a little surprised, but we opened another door, and the reading dropped back into the good range.

And I realized that very few people are truly aware of the need for indoor air quality, even activists, and even people who are careful to mask in larger gatherings or on airplanes.

Now I’m not measuring CO2 for its own sake – though the higher the CO2 level in a room, the more it makes you drowsy and slows down your brain processing during the time you’re in that space – but as a proxy for the risk of getting Covid or another respiratory virus.

Those viruses are spread in the air, so if you’re sick and exhale – or cough or sneeze – you put the virus into the air. When CO2 levels get above 800, we’re breathing in each other’s lung exhalations, so if one person is sick, we’re all going to be exposed.

There are things you can do about this.

The simplest one is to put more air in the room – open a window or a door, if they are available in that space.

It is possible to put in a heating and air conditioning system that includes good ventilation and also has a filtration system that takes viruses and other particles out of the air. It’s not particularly new technology and if you’re putting in an overall system, it’s not all that expensive.

But it is a lot more expensive than doing nothing, so very few places have done it as a retrofit.

So opening the windows or doors is still the default most places.

There is something cheap and practical you can do in buildings that aren’t being retrofitted and don’t have much access to outside air: you can get an air filter. In fact, if money is a real issue, you can build one cheaply using a box fan and MERV 13 filters. Continue reading “Avoiding Viruses”

Fixing the Air We Breathe Indoors

On May 15, ASHRAE — the association of engineers who work in heating, air conditioning, and ventilation — set out its Proposed Standard 241P, Control of Infectious Aerosols.

They are soliciting comments on it until May 26 from the public. Links and instructions for comments can be found here.

This standard, which was put together over six months — lightning speed for ASHRAE, which often takes years to develop new standards due to its painstaking process — was built on years of work by the organization on indoor air quality and included some input from public health experts.

According to ASHRAE:

The standard will address long-range transmission of infectious aerosols and provides minimum requirements for:

  • Equivalent outdoor air (combined effect of ventilation, filtration, and air cleaning) for use during Infection Risk Mitigation Mode
  • Room air distribution to reduce risk
  • Characterization of filter and air cleaner effectiveness and safety
  • Commissioning, including development and implementation of a Building Readiness Plan
  • System operation in Infection Risk Mitigation Mode during periods of high risk
  • Maintenance tasks and their minimum frequency
  • Residences and health care facilities

ASHRAE issued some recommendations early in the pandemic that provided guidelines for the kind of filtration that should be used in buildings to minimize transmission of airborne viruses. Those guidelines, though very good, were based on ongoing work on indoor air quality and did not include the kind of comprehensive work they brought to this new standard.

These standards, once incorporated into building codes and other regulations for buildings, will be a major step forward in making sure that the indoor air is safe to breathe. In a world in which many people spend most of their time indoors, that is a crucial element of public health.

These standards will minimize the transmission of airborne diseases including, but not limited to, Covid. Continue reading “Fixing the Air We Breathe Indoors”