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
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.
Thanks for your input. Very interesting. I did not know that SO2, CO, O3, and NO2 gas measurement were required by the EPA. Is the data avaliable to the public?
Your last commet "I'm sure there are simpler, less expensive, and less accurate options out there for measuring many of these pollutants" - this is what we would like to fined out. Are there accurate, but less expensive and easier to operate sensor systems for these gases? Who's woking on such things or have such devices avaliable?
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.
Thanks. You are right, Digi-key does indeed have some interesting gas sensors from Parallax, most of which are in stock and cost only $5 to $6. Then they have some sensor kits on a PCB for ~$29. 605-00008 METHANE GAS SENSOR 605-00011 ALCOHOL BENZINE GAS SENSOR 605-00009 PROPANE GAS SENSOR 605-00007 CARBON MONOXIDE GAS SENSOR 605-00010 CARBON DIOXIDE GAS SENSOR
Thanks. You are right, Digi-key does indeed have some interesting gas sensors from Parallax, most of which are in stock and cost only $5 to $6. Then they have some sensor kits on a PCB for ~$29.
605-00008 METHANE GAS SENSOR
605-00011 ALCOHOL BENZINE GAS SENSOR
605-00009 PROPANE GAS SENSOR
605-00007 CARBON MONOXIDE GAS SENSOR
605-00010 CARBON DIOXIDE GAS SENSOR