Guide to Managing Wastes for Laboratories: 
Section 3.1: Air Emissions In Labs AND How to Solve Them!

This guide was originally prepared by the U.S. EPA to provide information about small chemical laboratory environmental issues. EHSO has updated and revised it to make it more useful. Click here for the printable pdf version of the SMALL LABORATORY GUIDE  (814K) Be sure to ALSO see this page on OSHA lab standards and requirements !!!

The environmental management issues presented in this section either: (1) represent traditional areas with the most environmental management risk for small labs, or (2) are perceived to offer the greatest opportunity for environmental performance improvement. Not all issues may be of equal importance, but management of each is necessary to ensure continuously improving environmental performance.
3.1 Air Emissions

Often, air emissions from small labs appear to be subject to little or no regulation with some exceptions such as incinerators, large heating units, and lab processes emitting large quantities of hazardous air pollutants. Still, responsible lab staff should take steps to minimize emissions because even small, unregulated amounts of pollutants can be harmful to the environment. Many state, tribal, and local authorities regulate air emissions on a level at least as stringent as the Federal regulations. It is imperative that small labs check with the state, tribal or local authority to ensure the lab meets all applicable requirements and regulations.

Air emissions are also a potential occupational health issue. In 1991, OSHA recognized the unique nature of labs and established a separate lab standard (29 CFR 1910.1450) that requires a chemical hygiene plan that includes an assessment of potential personnel exposure to hazardous chemicals.
Regulatory Considerations

The Clean Air Act Amendments of 1990 (CAAA) established broad-reaching programs dealing with issues such as automobile emission standards, alternative fuels, and stratospheric ozone. But, of greatest potential concern to labs is Section 112 of the CAAA that addresses hazardous air pollutants (HAPs). Currently, 190 pollutants are listed as hazardous under Section 112, many of these are emitted from lab fume hoods. Common lab chemicals included on the list are benzene, formaldehyde, and methylene chloride.

Emission standards for many HAP source categories have been developed at the federal level and more are being added. Source categories include major industrial types (e.g., pharmaceutical manufacturing, synthetic organic chemical manufacturing) at which labs are often present. Interestingly, Congress also directed EPA to consider listing "research or lab facilities" as its own source category (CAA 112(c)(7)). EPA has not yet made a determination, but listing research or lab facilities as a separate source category would impact only large lab facilities which qualify as "major sources." It is unlikely that a small lab would be a "major source."

The primary mechanisms regulating air pollutant emissions are state, tribal, and local air quality control regulations. These regulations normally follow the Federal guidelines and have similar features. However, depending on the type of air pollutant issues within the state, Indian Country, or local air quality district, individual regulations will vary. Because air quality

regulations vary from state to state and even within a state, it is imperative that the lab check with their state, tribal, or local air permitting authority to establish exactly what requirements apply to the lab.

Title V Operating Permits. Title V of the CAAA establishes a permitting program for "major sources" of air emissions and for sources subject to certain New Source Performance Standards (NSPS) or National Emissions Standards for Hazardous Air Pollutants
(NESHAPs). Implementation of the program is delegated to authorized states and tribal governments.
In some instances, small labs may be regulated under a Title V program because they are located in facilities with heating/cooling plants or other large
emission points that qualify the entire facility as a major source.

State Permits to Construct and Operate. State air pollution control regulations may mandate that individual air pollution source and control devices (e.g., individual boilers, lab hood stacks, sterilizer, etc.) have permits to "construct" and permits to "operate."
State regulations governing permits for emissions from lab fume hoods vary widely. Many states clearly exempt lab emissions from permitting requirements, while other states have no special exemption. Further, some states have developed special registration requirements for lab fume hoods.

Permits may also be required for air pollutant emissions from facility heating equipment such as boilers. Permits are typicaly required for the operation of boilers with heat input capacities equal to or exceeding 1 million Btu/hour; however, some states require permits for smaller boilers. Also, sources such as incinerators and paint spray booths are often subject to air permitting requirements.

In addition to the routine lab and building management operations which may be impacted by air pollution control regulations, labs may encounter the following non-routine or less common operations that will trigger air pollution control regulations:

Ozone Depleting Substances. Pursuant to the CAAA, EPA developed regulations that limit emissions of ozone-depleting substances (ODSs) such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) used in air conditioning and refrigeration equipment and halons used in fire suppressant systems. EPA regulations prohibit venting and

require recycling of these materials during equipment servicing, repair and disposal. Service personnel must be trained and certified by EPA or an EPA-approved organization.

The production of CFCs was banned as of December 31, 1995. HCFCs will also be phased out over the next thirty years. The first HCFC phase out, for R-22 in new systems, will be in 2010. The final HCFC chemical phase out will be for the production of R-123 in 2030.
Heating, ventilation and air conditioning equipment that use these CFC and HCHC refrigerants should be upgraded or replaced with "chlorinefree" refrigerant systems as alternative systems become available to avoid the high cost of obtaining these out-of-production chemicals. Certain lab analytical uses of CFCs have been permitted beyond the phase-out deadline set by the Montreal Protocol because the EPA has declared them as "essential use." As of January 1, 2000, however, EPA may no longer be able to allow lab essential use exemptions because the Act does not specifically list lab and analytical uses as an exemption in the phase out.

Chemical Accident Prevention. In response to the CAAA, EPA developed regulations that establish requirements to prevent or respond to accidental releases of extremely hazardous air pollutants (40 CFR 68). Facilities storing above threshold quantities (TQs) of designated toxic or flammable substances in one process area will have to identify the possible hazards and develop a Risk Management Plan (RMP). However, EPA generally excludes the chemicals used in labs from the requirements because small quantities are stored (40 CFR 68.115).
Chemicals used outside the lab (e.g., chlorine chemical treatment system for building
water supply), in specialty chemical production processes, or in pilot scale operations are not exempt from the RMP process.

Air Pollution Episode Planning. The CAAA classifies non-attainment areas for the purpose of developing air emergency episode or contingency plans. Contingency plans require states to specify emission control actions and notification procedures that will occur when air pollution concentrations reach a certain level. Implementing the control

actions should prevent air pollution from reaching levels that would cause imminent and substantial damage to human health. Regions are classified separately for each of the following pollutants: sulfur oxides, nitrogen dioxide, particulate matter, carbon monoxide, and ozone. Requirements for a contingency plan vary depending on the region's classification. Lab facilities in non-attainment areas may be required to prepare a plan detailing steps the lab will take to comply with requirements on shutting down operations that produce air emissions and notifying personnel of the shut downs. Depending on the alert stage, labs may have to cease incineration operations, curtail motor vehicle operations, alter boiler operations, or shut down all lab activities. Labs that are part of a larger manufacturing operation are more likely to be affected by such requirements.
NSPS. Performance standards have been established (40 CFR 60) for new air pollution sources according to industry (e.g., chemical production plants, metal smelters, and manufacturing operations) and emission sources (e.g., steam generating unit such as boilers, incinerators). These sources often face stringent air pollution control regulations such as limitations on pollutant emissions, periodic or continuous emission monitoring, and installation of air pollution control equipment. Labs that install or have recently installed a particular type of equipment or are part of a large industrial facility covered under NSPS regulations may be subject to these more detailed requirements.

NESHAP. EPA has also promulgated stringent air pollution control requirements for emissions of certain HAPs (e.g., mercury beryllium, radionuclides), emissions from certain HAP sources (organic chemical manufacturer, sterilization facilities), and emissions from certain equipment (e.g., oil-water and organic-water separators) (40CFR 61 and 63). In addition, a lab's radionuclide emissions may be subject to NESHAP regulations if the lab does not have a Nuclear Regulatory Commission license and are a non-DOE Federal facility (owned or operated), (40 CFR 61, Subpart I). Furthermore, on-site demolition, renovation and removal of asbestos-containing materials (ACMs) in existing structures on-site may be subject to the NESHAP regulating asbestos (40 CFR 61, Subpart M).
Management Issues

In order to understand regulatory requirements, P2 opportunities and other management requirements, the lab must first identify its air emission sources and quantify actual and potential emission levels.

The lab should prepare and maintain a list of actual and potential air emissions in the lab (fume hoods, stacks, vents, etc.) including the source and location of emissions, and an estimate of the type and quantity of emissions. Potential emissions from such activities as cleaning, painting

and floor care should also be included in this inventory. The inventory should be updated at least annually.

Quantifying emissions from discrete equipment such as a boilers or incinerators is fairly straightforward. However, accurately quantifying small lab air emissions that consist of hood or area exhaust emissions of various chemicals is often difficult. For example:
Some non-routine lab processes may have little or no records on chemical usage;
Chemicals can change phase in the course of lab work. A liquid can become a part of a solid or a solid reactant can become a volatile gas;
Researchers may purchase and use chemicals that are outside of a centralized management system; and
Chemical volatility varies with temperature and pressure.

One way to estimate air emissions is based upon a simple mass balance model such as the one following. This model relies on accounting for all possible uses of the chemical so that the remainder that can not be accounted for is the maximum amount that could have actually been emitted to the air.

Text Box:  PAGE 16


For each specific air volatile chemical,

Fill in quantities known or estimated.



(A) Amount of unused chemical in inventory today.


(B) Amount of same unused chemical in a previous

inventory. Note: A long period of time (i.e., one year)

between (A) and (B) may yield more accurate results.


(C) Subtract (A) from (B). This is the difference in inventory

over the time period.


(D) Amount of chemical purchased and received in the time

period covered by the inventory records used in (A) and (B).


(E) Add (C) and (D). This is the amount that needs to be

accounted for.


(F) Amount of chemical still in use in solutions and mixtures.


(G) Amount of chemical disposed of as waste (all forms).


(H) Amount (non-waste), shipped off-site, or other off‑

premise use.


(I) Subtract (F) through (H) from (E).

This is the maximum amount of the chemical that could

actually have been emitted to the air from the lab over

the period of time between (A) and (B).


Although it might seem like an overwhelming task to make a calculation for all chemicals in a lab, this is probably not necessary. To start, the most air volatile and commonly used chemicals, such as organic solvents, should be addressed as well as any especially hazardous or stringently regulated chemicals. Thus, after making calculations for a small subset of chemicals, lab staff should have a good understanding of emission levels.

A second approach centers on evaluating a specific lab process instead of the entire lab. This approach will be easier and more reliable in labs where analyses are routine. For example, suppose a routine test mass balance calculation repetitively indicates a 10% "loss" of a chemical. "Loss" means the chemical is not part of the product or the solid waste stream. Thus, one assumes it is emitted to the air. This percentage can then be used to
estimate the maximum total mass of chemical that could actually be emitted by multiplying the loss per test by the total number of tests.

Implementing Once air pollutant sources are identified and emissions are quantified, the
the Air lab must:
Quality Assess the regulatory implications of these emissions;
Program Assess P2 opportunities to eliminate or reduce air emission sources;
Ensure that the sources are properly permitted;
Maintain operation, monitoring and maintenance programs to comply with regulation or permit requirements; and
Comply with recordkeeping requirements.

Ventilation Ventilation is an integral part of controlling and removing particulates, vapors, gases, and other airborne chemicals from the lab and exhausting them to the atmosphere. Types of ventilation devices used in labs include fume hoods, biological safety cabinets, glove boxes, extraction hoods, benchtop slot hoods, and flexible ducting. Any ventilation device used must meet the design requirements set forth in EPA, OSHA, American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), and National Fire Protection Association (NFPA) regulations.

The lab should implement a regular inspection and monitoring program to ensure all ventilation devices are working properly to remove contaminants from inside the lab and exhaust them to the exterior of the building. All lab fume hoods must meet the ASHRAE 110 standards for testing the performance of lab fume hoods.
Ventilation is measured in air changes per hour (ACH). OSHA recommends lab ventilation systems have a ventilation rate of 412 ACH, NFPA 45 recommends greater than 8 ACH, and ASHRAE recommends a

rate of 610 ACH. The lab should ensure its ventilation rate meets the highest minimum recommendation as well as local code requirements.

In order for ventilation devices to be effective they must be used properly. Before any person uses a ventilation system, they should receive training in operating procedures as well as procedures for daily inspection. Good lab practices should be implemented to reduce the user's exposure to airborne hazards. For example, keep all containers at least six inches from the front of the hood, keep the hood sash closed as much as possible, do not obstruct the baffles in the rear of the hood, keep all containers tightly closed when not in use, and do not store unused chemicals in the fume hood.

Pollution Prevention and Air Emissions
Labs can eliminate or reduce air emissions through process change and engineering controls. In addition, a reduction in the scale of the experiment can reduce air emissions. Over the last decade, microscale chemistry has come to be considered a proven technology to reduce air emissions and P2 in other ways (see Hazardous Materials Handling and Storage, Section 3.14).

Other simple solutions such as ensuring the lids remain tightly closed on volatile solvents when not in use will also prevent air emissions. A good example is a high purity solvent delivery system being offered by some chemical suppliers that can accurately dispense solvents directly from the containers. The solvent is stored under inert gas and gas pressure drives solvent dispensing. When the container is empty, it is shipped back to the supplier to be refilled. This reduces the potential for emissions during chemical transfer.

Text Box:  PAGE 19




1.    Determine if the facility is required to compile an air

emissions inventory and if it is completed.


2. Determine and record any changes in emission levels

since the last inventory.


3.    Based on the inventory, determine if the facility is

considered a "major source."


4.    If the lab emits air contaminants to the outdoor

atmosphere (through stacks, vents, and exhausts), make

sure that a plan approval, operating permit, or exemption

was obtained and documented if required.


5.    If an air emission permit is needed:


       Ensure that all of the lab's permits to operate sources

of air emissions are up-to-date; and

       Ensure that there is a system for timely renewal of air

permits and associated fees.


6. Regularly observe and document emissions from

emission points to determine whether smoke or odors

are produced.


7.    If the lab is part of a large industrial facility determine if

more stringent air regulations must be followed.


8.    Determine if the facility triggers requirements under



9.    Determine if the lab properly services, repairs, and

disposes of ozone depleting substances (e.g., CFCs and

halons) and associated equipment.


10. If lab storage exceeds threshold quantities of a regulated

air pollutant, verify the facility developed and submitted a

RMP and ensure there is a procedure in place to update

the plan.


11. Determine if lab ventilation is adequate for the

associated hazards.



Text Box:  PAGE 20




12. Verify that ventilation meets design requirements set by

ASHRAE, EPA, OSHA, and NFPA regulations.


13. Ensure the lab developed and implemented a ventilation

monitoring program which includes:


         Daily visual inspections;

        Testing and certification at least annually; and

        Annual maintenance (or sooner if necessary).


14. Determine if the lab implemented any P2 measures such

as engineering controls.


15. Ensure the lab encourages personnel to tightly close all

containers when not in use to minimize air emissions.