SimSmoke

The USEPA has announced the revision of their 24-h National Ambient Air Quality Standards (NAAQS). The 24-h standard for fine particulate matter was reduced from 65 to 35 micrograms per cubic meter (μg/m³).

This is an important development, because it indicates that the USEPA has reviewed many peer-reviewed studies, and they have found that harm can occur from exposures to fine particles that exceed the new, lower level.

The U.S. Surgeon General has released its anticipated report "The Health Consequences of Involuntary Exposure to Tobacco Smoke".

Important findings of the report include (paraphrased):

• Secondhand smoke (SHS) causes death and disease
• SHS has immediate (acute) health effects
• There is no risk-free level of exposure to SHS
• Only the elimination of smoking can protect nonsmokers

Two new research papers on the simulation of exposure to secondhand smoke occurring in residences are being published in the journal Atmospheric Environment, authored by Dr. Neil Klepeis and Prof. William Nazaroff. (links: 1 , 2).

These papers contain detailed simulation results of likely exposures that can occur in homes for a variety of ventilation conditions and occupant behavior patterns.

When we at SimSmoke.Org developed the computer simulations used here to estimate secondhand smoke exposure levels, we validated them using real-time air pollution monitoring instruments. It was important for us to verify the results of exposure estimates using numerous measurements in bars, restaurants, homes, and cars.

The instruments for measuring airborne particles typically operate by drawing air into a tube and analyzing the amount of light that scatters off the particles in the air stream when struck by a laser beam or other light source. The amount of light scatter can be related to the mass of particulates that are present in the air.

As reported on the KABC website, today the city of Calabasas, California began a strict ban on smoking in public outdoor spaces within 20 feet of places that people congregate.

Neil -
I echo Martin's comments: thank you for putting this info on-line, and for your earlier work on outdoor smoking. With legislative moves towards non-smoking in bars and similar premises in Australia, there is now a lively debate (which, with the exception of Queensland, health interests are not generally winning) about how enclosed or unenclosed a place should be before before smoking is permitted/prohibited.

We actually have laws which say that as long as a place is more than 25% open (perimeter walls + ceiling, or sometimes just a % of wall area), it's OK to smoke.

Policy officers have been unable to find relevant information which associates degree of enclosedness with level of passive smoking exposure/risk for customers and staff.

I just added a new simulation for SHS concentrations in smoking and nonsmoking rooms of a bar or restaurant. Check it out here.

I've added particle deposition to the simulations. The inclusion of particle loss due to deposition onto surfaces doesn't change the results very much, but it is a well known phenomena that acts to reduce airborne levels of SHS particles. Ventilation is usually a much stronger factor than deposition in removing SHS particles from a given location.

This simulation is of smokers in an enclosed (indoor) bar or restaurant over a 2-hour period where there are designated smoking and nonsmoking rooms. The two rooms are well-mixed and connected by a doorway or open passage.

You may select the dimensions of each room (Length x Width x Height in feet), the overall rate of outdoor air exchange (h^-1), which is apportioned to each room according to their volumes, the air flow rate between zones (m³ h^-1), which is currently the same in each direction, and the total number of cigarettes smoked in the smoking room of the venue over the 2-hour period.

Multiple smokers can be active simultaneously. Each cigarette lasts 10 minutes. Cigarette starting times are assigned randomly. A given cigarette has an equal chance of being lit during any minute of the 2-hour period.

California seems to be where precedents are set in tobacco control yet again, as judged by the following news item.

Plese visit CNS News for the complete story.

An excerpt follows:

[original posting edited by NK]

"The city of Calabasas, Calif., voted unanimously Wednesday night to ban smoking in all outdoor places, including sidewalks and streets, except for small outdoor 'smoker outposts.'"

"The 'smoker outposts' would be established by businesses in areas like parking lots. Smokers can also smoke when no one else is around or expected. The ban is considered the most sweeping ban of any U.S. jurisdiction."