Skip navigation
Digi-Key TechXchange Communities > Projects and Designs > Discussions
20547 Views 4 Replies Latest reply: Nov 2, 2011 10:01 PM by JimHarrison RSS
Currently Being Moderated

Oct 25, 2011 4:01 PM

Sensors for air quality

They tell me that in the 60’s when you were on the hills of the San Francisco peninsula, where I-280 runs, the view was clear as a bell almost every day. Looking over those trees and valleys today it is never real clear. The air is a bit fuzzy. Could be water vapor or fog, but I doubt it.


They tell us the air quality has been improving since they put the reins on auto emissions in the 70’s and 80’s – but I’m not so sure. The air polution reports in the newspaper show green/yellow/red for both ozone and fine particles. Are other items in the air we could/should be watching and do we have sensors for those? Are these sensors cost effective?  –  Jim Harrison

  • MetMan Apprentice 93 posts since
    Oct 24, 2011
    Currently Being Moderated
    Oct 26, 2011 8:59 AM (in response to JimHarrison)
    Sensors for air quality

    Air quality is certainly more regulated than it used to be back in the day, especially in California 


    The Government has established regulations for monitoring air quality and defining what acceptable levels of pollution are.  There are several measurements required by the EPA and other organizations (such as the California Air Resources Board):


    PM2.5:     Fine particles less than 2.5micron in size.  This is a very important measurement because this size particulate is what is absorbed by our lungs and so has the largest health impact on us.


    PM10:     Larger particulate matter up to 10micron, less impact on human health.  (but still part of the 'haze').


    Gases:    SO2, CO, O3, and NO2


    Chemical Speciation:    Measures levels of metals, ions, and carbon constituents suspended in the air.  Lab analysis is performed on particulate pollution samples to find out how much is dangerous material.



    PM2.5 fine particulate levels in the US are legally required to be <50 ug / cubic meter.  Parts of India, the Phillipines, China and many other places have PM2.5 levels that average more than 10 times our legal limit!!! so we can be thankful for our enforced regulations. 


    Many of the sensors/monitors used in these networks cost many thousands of dollars and require a lot of technical expertise to use and to analyze the data.  I'm sure there are simpler, less expensive, and less accurate options out there for measuring many of these pollutants.

  • Novice 1 posts since
    Oct 31, 2011
    Currently Being Moderated
    Oct 31, 2011 8:46 PM (in response to JimHarrison)
    Re: Sensors for air quality

    Check out Figaro Sensor. I've had lots of fun making gas sensor circuits with their sensors. They aren't too expensive if you want to monitor your immediate surroundings and you don't need an absolute calibration. Also it looks like Digikey carries some similar items from Parallax.

More Like This

  • Retrieving data ...

Bookmarked By (0)


  • Correct Answers - 4 points
  • Helpful Answers - 3 points