Links to resources

There will be previous studies, blogs, or manufacturer's websites that can provide information for this group. The first one here is the EPA sensor website that includes an evaluation of low-cost monitors. It can be found at:

The Dylos and Speck monitors are among those evaluated.

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  • Here is a link to the Health Canada site that references indoor air quality guidelines:

    If you want to explore the arcane world of oxides of nitrogen or volatile organic compounds (VOCs), neither of which ROCIS measures, this website is a good place to start.

    Residential indoor air quality guidelines -
    The Residential Indoor Air Quality Guidelines summarize the health risks of specific indoor pollutants. The guidelines recommend exposure limits for…
  • ROCIS has been tracking carbon dioxide (CO2) concentrations in participants' houses. We see frequent measurements > 1000 ppm and some excursions to 3000+ ppm. The science on health effects of CO2 has been evolving quite quickly lately. There are now several studies relating CO2 concentrations as low as 1000 ppm with cognitive effects. Here is a link to one abstract Azuma et al

    Most often, the high measured CO2 concentrations we see are during the night in a closed-door bedroom. Do we need cognitive excellence while sleeping? Are there any other problems, or benefits, from having higher CO2 concentrations in bedrooms overnight?

    Effects of low-level inhalation exposure to carbon dioxide in indoor environments: A short review o…
    Environ Int. 2018 Dec;121(Pt 1):51-56. doi: 10.1016/j.envint.2018.08.059. Epub 2018 Aug 30. Research Support, Non-U.S. Gov't; Review
  • Here is a link to a presentation by Richard Corsi (University of Texas) on the next level of indoor air interactions:

    ROCIS has been concentrating on the some of the more obvious airborne pollutants (CO, radon, particles) where Corsi's work deals with both chemical reactions and pollutant emissions/removal by buildings and their contents (including people). He touches on such matters as how resuspended particles can have a different and more dangerous chemical content than those particle had before they landed. He also talks about what room contents (carpets, furnishings, occupants) have the greatest effects on particle and gas adsorption and re-emission.

    It sounds deep but he is an engaging speaker and can make the topic very interesting. Wouldn't you want to know the significant effects that male body sprays are having on classroom air?

    Architecture Department Fall Lecture Series: Richard Corsi
  • ROCIS monitoring has shown that both portable filters and upgrades to furnace filters provide reliable and significant particle reductions in homes. The EPA has updated its publications on residential filtration and they are worth consulting. The 7-page summary, Guide to Air Cleaners in the Home, describes the range of air cleaners that can be used for particles or chemical contaminants. The full 74 page report, Residential Air Cleaners - A Technical Summary , gives more detail on filter performance and selection. It is probably best to consult the short document first and then delve into the longer report for specific details, if needed.…
  • This equipment is used in the ROCIS Low Cost Monitoring Project. Here are manufacturer websites for additional information.

    Equipment Summary & Features


    DYLOS 1700 AIR QUALITY MONITOR (3 per kit)

    • According to the Dylos literature, it measures particles above 0.5 microns “Dylos small particle count” & above 2.5 microns “Dylos large particle count.” Particles are measured in µm, by count. NOTE: Human hair is 60-70 µm in diameter. 
    • The scale (on back of monitor) “excellent to poor” is only for the small particles
    • Can store up to 1 week of minute data before overwriting it
    • Can run on battery for short period (~2 hours)
    • Manual view (toggle through) can provide minute average counts for the past 60 minutes, the hourly average counts for the past 24 hours or the daily average counts for the past 30 days
    • For more info:
    • Provides 1-day, 7-day, & long-term average radon levels (reading switches back & forth)
    • Measures radon concentration in pico-Curie’s per Litre
    • No data logging or downloading option
    • We recommend not moving for the 3-week duration; reset data only if you change location

    • Monitors low level carbon monoxide (CO) down to 7 ppm
    • Conventional US residential CO alarms do NOT measure levels of CO below 60 ppm
    • No data logging or downloading option
    • Can view CO levels over time to identify time of incident
    • Ideally the CO monitor should read “0” at all times
    • Sources of CO are combustion appliances (space & water heaters, dryers, cook stoves, wood stoves, & fireplaces), indoor smoking, & vehicles in attached garages
    • CO2 is an indication of the ventilation rate & occupancy of a building
    • CO2 levels will vary with occupancy – CO2 goes up when more people are present
    • This CO2 monitor stores CO2, temperature, & RH; (1 month @ 15 minute resolution
    • Note: some settings can be lost when monitor is unplugged for an extended period
    • Confirm your monitor shows the correct date & time stamp, & that “rec” is visible on the screen
    • For more information:

    ROCIS_LCMP_Equip Summary.pdf

    DC1700 BATTERY OPERATED AQM description comes here....
  • Here is another link, not to the paper itself but to a report on its implications. This involves an LBNL study on the utility of low-cost monitors (such as Dylos) to alert and protect householders. Here is the URL:

    The study found that the monitors were notably less accurate than engineering test tools but they did serve a purpose in identifying high concentrations of particles. Most did poorly or did not measure the smaller particles (e.g. < 0.5 micron) which can also be hazardous. The Dylos monitor used by ROCIS participants counts only particles 0.5 micron or larger.

    Mixed report card for low-cost indoor air quality home monitors: Study finds they can be helpful du…
    Indoor air researchers recently tested seven consumer-grade air quality monitors to see if they could detect fine particles emitted by common househo…
  • For those of you who wish to know more about the health risks of indoor particles, here is a link to the report from a National Academy of Sciences workshop held in February of 2016:

    It is a comprehensive report assembled and reviewed by the experts in the field. It is also reasonably easy to read.

  • This link is to the recent National Academy of Sciences two day conference on particles in houses and their health effects. It has links not only to videos of the presentations but also the PowerPoints themselves so you can view them at your own speed. There are some findings that seem to contradict what we are seeing, largely in the particle penetration rates. There is no better current reference.

  • Health Effects of Indoor Exposure to Particulate Matter, February 10 and 11!  Check out the webcast of a meeting taking place this week in Washington DC, hosted by the National Academies of Sciences  Engineering & Medicine

    Here is the link to info about the meeting, as well as the link to register for the webcast.

    Nine hours of presentations! - it should address a number of questions that have surfaced from the ROCIS LCM project. Sessions  will address: 1) Sources; 2) Particulate Dynamics & Chemistry; 3) Exposure Levels and Characterization; 4) Exposure mitigation; 5) Identified & Emerging Health Concerns; and 6) Interventions & Risk Communication.

    Agenda is attached.

    AgendaIndoor PM 2416_Feb 10-11, 2016.pdf

  • Here is a short blog post that I wrote a few weeks ago called, "Visualizing Air Quality".

    It provides a few links to air quality resources as well as an excel graph that I created using hourly data collected from three Dylos Air Monitors this summer.

    P.S. I wrote it rather quickly and may have misstated the particle sizes that the SPECK counts. If someone would like to correct me, I'd be glad to have the post edited.

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