#99 - Beijing Air Index Goes Off Scale

I recently noticed a couple of blog posts about high air pollution levels in Beijing, China on the Chem.info website.*

Recent photos from Beijing, China.

Discussions of air pollution and urban smog often include references to PM-2.5 and PM-10. These terms refer to the size of particulate matter that is entrained in the breathable atmosphere. The numbers in the ‘PM-‘ expressions refer to particle size in micrometers.

Basic particulate size categories

The implications of the distinction between PM-10 and PM-2.5 are significant. The PM-10 particle is sufficiently small to move past the natural defenses in the human breathing system and accumulate in our lungs. The PM-2.5 particle is sufficiently small to diffuse from the lungs directly into the bloodstream.

Smog is a complex mixture of constituents from
a variety of sources.

To evaluate the profusion of particulate matter, environmental authorities use automatic air samplers. These instruments collect air samples at very specific and constant air flows. Unwanted particulates above the target size are removed by filters, baffles, and very specific air flow designs within the sampler. The remaining particles impinge on a removable filter element which can be gravimetrically analyzed to determine particulate profusion. A few different styles are shown below.

a) Dichotomous sampler - separates and captures PM-2.5 and PM-10
b) Size-Selective Inlet sampler -  can capture PM-2.5 or PM-10
c) High Volume sampler - can capture PM-44 and less

Smog is obviously not a problem unique to Beijing only. Daily air quality reports are available in various countries to provide the public with air quality information. For example, here are the internet-based air quality reporting tools for USA and Canada. The Chinese government has recently implemented air quality reports that are updated hourly.

At Nova, we don’t manufacture particulate samplers. However, industrial gas analyzers are frequently used to help control air pollution at the sources. For example, an out-of-tune combustion process may produce more particulate matter due to improper fuel ratios or combustion conditions. The exhaust gases can be used to determine combustion efficiency which can then be improved if needed. Steel-making processes, such as electric arc furnaces, can also be optimized and environmentally improved by using gas analysis. The Tenova EFSOP process is an industry-leading example of this.

For information on gas analyzer systems, give Mike or Dave at Nova a call, or send us an e-mail.
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com
http://www.nova-gas.com/
https://twitter.com/NOVAGAS
http://www.linkedin.com/company/nova-analytical-systems-inc-
http://www.tenovagroup.com/

* Chem.info Article 1, Article 2

Pictures:
Dichotomous sampler - http://www.esrl.noaa.gov/gmd/obop/mlo/programs/old/partisol/partisol.html

High volume sampler - http://www.esperanceport.com.au/envmon.asp

Size-selective sampler - http://www.hi-q.net/products/outdoor-high-volume-air-samplers/pm-10-series-high-volume-air-samplers/default.html

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