How an air monitoring survey works, step by step

This page explains what the rules and common practice call for. Every site is different, and what a survey or a filing needs at your facility is something we work out with you after we see it.

We come to your plant, sample the air your workers breathe for a full shift, and hand you a defensible report.

That sentence says more than it seems to. Search for air monitoring and much of what comes back is one of two things: laboratories that will analyze a sample you collect yourself, or vendors that will sell you a pump and a manual. Each one supplies a piece of the job, but neither puts a person in your plant at 5:45 a.m., checking equipment before first shift.

We do. We have worked on site since 1993, in aerospace, electronics, steel fabrication, foundries and semiconductors. We are based in Arizona and work on site across the United States.

What we sample for

If a substance has an OSHA permissible exposure limit (PEL), we can sample for it. The same goes for a substance with an ACGIH threshold limit value (TLV), and for a hazard OSHA could cite under its General Duty Clause, which covers serious recognized hazards.

How a survey runs, step by step

Step 1. A short planning call. We ask about your processes, your substances, your job classifications and your shifts, which usually takes 20 to 30 minutes. What we are working out is how many similar exposure groups (SEGs) you have, meaning sets of workers who do the same job the same way. The number of exposure groups, not headcount, sets the size of the project. → How many samples do you need?

Step 2. A written scope of work and a fixed price. The proposal gives you the number of samples, the substances we will sample for, the analytical methods, the turnaround time and a price. That price is fixed, not an hourly estimate that drifts. → What drives the cost of a survey

Step 3. Sampling at your site. The method calls for calibrating the flow rate of every pump against a primary standard, which is a reference flow meter, before the shift starts. The pumps then go on your workers for the shift, with checks along the way and notes on what is running, which controls are on, and anything unusual about the day. After the shift, every pump is checked against the primary standard again. Full shift means full shift.

Step 4. An accredited laboratory analyzes the samples. The laboratory uses the published NIOSH and OSHA methods appropriate to each substance.

Step 5. The report. It compares your results with the PEL and the action level that apply to you, and results at or above the action level can trigger periodic monitoring. A useful report also shows the calculation behind each 8-hour time-weighted average (TWA), the periodic monitoring schedule your results trigger, and recommendations in plain language. → See sample reports

Step 6. What happens next. If you are above a limit, a clock is running: you have 15 working days to notify your workers, in writing. You also need to talk through how to bring the exposure down. We will walk you through both, and that call is included.

Why laboratory accreditation matters more than it sounds

When an employer contests an OSHA citation, a result from an unaccredited laboratory is the first thing that gets challenged, and it is also the easiest thing to challenge.

Accreditation means an outside body audits the laboratory against the methods it claims to run, and the laboratory also takes part in proficiency testing, a regular external check of its results. It is a third-party fact you can verify, not a marketing claim. Your data may have to stand up to an inspector, an insurer or opposing counsel, and that is when the difference carries weight.

Any exposure monitoring report you are handed should name the laboratory and the analytical methods, so that both can be verified.

What makes a survey defensible

Hanging a pump on someone is the small part, and the items below are what separate a report that protects you from one that does not:

• Exposure groups defined by task and material, not by job title. Org charts describe management, not what people breathe.
• Enough samples for each exposure group to support the conclusion, because a single sample is only an anecdote.
• Full-shift samples, or task-based samples with the time-weighting done properly and the task durations documented. A 2-hour sample multiplied by 4 does not qualify.
• Pump calibration records from before and after the shift, against a primary standard.
• Field notes written on the day, covering what was running, which controls were on, and what was unusual.
• Published methods named by number, so someone else can reproduce the analysis.

Surveys usually fail on the documentation, not the chemistry: the numbers were fine, but no one could show what they were numbers of.

We work across the United States

We are based in Arizona and work on site across the United States.

An air monitoring survey is a 1- to 3-day visit to your site, which makes the economics very different from cleanup work. Travel is a modest share of the total cost, which is why buyers routinely hire from out of state for this work, and it is a sensible choice.

If you run a plant in Ohio with a hexavalent chromium problem, the nearest firm that has actually surveyed stainless steel welding may be in Phoenix, and hiring that firm is a sound choice.

Arizona clients: → Phoenix · Tucson · Mesa · Chandler · Scottsdale · Tempe

When you may not need this

This is worth saying plainly, because it comes up often.

• Silica, hexavalent chromium, beryllium and formaldehyde. The OSHA standards for all four include options that let you rely on existing data, which OSHA calls objective data or the performance option. If you have data that truly represents your workers' exposure, you may be able to meet the standard without taking a sample.
• Lead and cadmium are different, and lead is stricter than people think. The cadmium standard lets you use historical monitoring results and objective data, but only in place of your initial monitoring. The lead standard has no objective data option at all. What it has is historical monitoring data with a hard cutoff: you may rely on lead air measurements made in the past 12 months, and nothing older. Neither standard allows any substitute for periodic monitoring, so objective data will not carry an ongoing lead program.
• You may not be due yet. Each standard sets its own schedule for periodic monitoring, and the schedules differ more than people expect. → How often OSHA requires air monitoring, by substance
• ADOSH offers free on-site consultation to Arizona employers. ADOSH is the state OSHA plan, and its consultation service does include personal air sampling. It is separate from enforcement, and no citations are issued for hazards you correct promptly. The consultant's written report is also confidential, because a federal rule bars the state from sharing it with anyone but you. For some employers it is plainly the right first call, and we will say so.

Know these three things before you assume the free program fits:

1. The program is aimed at smaller businesses in higher-hazard industries, so larger manufacturers get lower priority. That is the limitation most of our clients run into.
2. The confidentiality has two exceptions: the consultant must refer an imminent danger to enforcement if you do not act, and a serious hazard not corrected within the agreed time gets referred as well.
3. The visit is set up as consultation, not to build a record for a contested case. That is a difference in purpose, not in skill.

A short conversation usually shows which of these applies to you, and we would rather have that conversation than sell you a survey you do not need.

Who does the work

Ron Fleming has walked plant floors since 1993 and plans every project himself. His son Marcus has joined the business and is learning it on site with him.

What we do not claim: we do not hold the Certified Industrial Hygienist credential (CIH), and we do not imply that we do. What we have is work in real plants since 1993, a nationally accredited laboratory (accredited under the federal NVLAP program) behind every number, and reports you can read before you hire us.

→ See sample reports

Common questions

How long does it take? Most single-substance surveys take 1 day in the field, and work that covers several substances or several shifts runs 2 to 3 days. Rush laboratory turnaround is available, but it is worth paying for only if you are up against an OSHA abatement date.

Do you need to shut down production? No. Sampling happens during normal operations, which is the whole point, because a survey done on an unusually slow day does not tell you anything.

What do you need from us beforehand? We need a description of your process, a count of workers by job classification, the safety data sheets for the materials you use, and any previous monitoring results. Sending these ahead reduces field time and cost.

We already provide respirators. Do we still need monitoring? Almost certainly yes. OSHA's respiratory protection standard requires you to identify and evaluate the respiratory hazard, including a reasonable estimate of employee exposure. The standard also covers what happens when you cannot reasonably estimate it: you must then treat the atmosphere as immediately dangerous to life or health.

Beyond that, respirator selection depends on knowing the airborne concentration of the substance. Any substance-specific OSHA standard that applies to you also has its own monitoring requirement, regardless of what personal protective equipment is worn. Issuing respirators is not an exposure assessment. → Do respirators replace air monitoring?

We just got cited. → OSHA cited us for no air monitoring. What now?

Can you do noise at the same visit? Yes, and you should. Workers can wear noise dosimeters while the sampling pumps run, on the same trip, whereas scheduling the two separately means paying to get someone to your plant twice. → Noise surveys

All our air monitoring pages

• Acid Mist Monitoring: Sulfuric Acid and Hydrogen Chloride Air monitoring for sulfuric acid mist and hydrogen chloride: the OSHA, NIOSH and ACGIH exposure limits, common sources, and the sampling details that matter.
• Ammonia Air Monitoring: Exposure Limits and Sampling Ammonia exposure monitoring: the OSHA PEL and NIOSH limits, common sources, full-shift and short-term sampling, and when you may not need a survey.
• Benzene Air Monitoring: PEL, STEL and Action Level OSHA has two sets of benzene limits, ten times apart. See which standard covers your work, how we sample, and what your monitoring results require.
• Beryllium Air Sampling and Exposure Monitoring OSHA's beryllium standard requires an exposure assessment wherever workers may be exposed at all. See the limits, how we sample, and when monitoring can stop.
• Cadmium Air Sampling and Exposure Monitoring One result below the action level does not end cadmium monitoring. See the PEL and action level, common sources, how we sample, and what OSHA requires.
• Carbon Monoxide (CO) Exposure Monitoring Carbon monoxide is the one gas a direct-reading meter can measure by a validated OSHA method. See the limits, common sources, and how a same-day survey works.
• Formaldehyde Air Monitoring: OSHA PEL, STEL and Action Level OSHA's formaldehyde standard ties periodic monitoring to the action level and the STEL. See the exposure limits, how we sample, and what your results require.
• Hexavalent Chromium Air Sampling and Exposure Monitoring Hexavalent chromium has a low PEL and is easy to sample incorrectly. See where it occurs, how we sample for it, and what your monitoring results require.
• How an OSHA Air Monitoring Survey Works, Step by Step We come to your plant, sample your workers' exposure for a full shift, and deliver a defensible report. Here is each step of an air monitoring survey.
• Hydrogen Sulfide (H2S) Air Monitoring and Exposure Limits Federal OSHA has no 8-hour TWA limit for hydrogen sulfide in general industry. See the limits that do apply, how we sample, and why odor cannot be trusted.
• Isocyanate Air Sampling: HDI, MDI and TDI Exposure Monitoring Isocyanates require derivatizing media, or the sample fails without warning. See where they occur, the exposure limits, and how we sample for HDI, MDI and TDI.
• Lead Exposure Monitoring Under the OSHA Lead Standard OSHA's lead standard differs from other standards in ways that cost money. See the PEL, the 7-hour sample rule, periodic monitoring and record retention.
• Manganese Air Sampling and Exposure Monitoring OSHA's manganese ceiling limit is far above current health-based limits. See where manganese exposure occurs, how we sample, and what your results mean.
• Metal Fume Fever: Zinc Oxide and Copper Fume Air Monitoring Metal fume fever resembles the flu and clears in two days. See the sources of zinc and copper fume, the exposure limits, and how we sample for them.
• Respirable and Total Dust Air Monitoring (PNOR) OSHA's general dust (PNOR) limits apply only when no specific standard covers the dust. See the limits, wood dust history, how we sample and when to skip it.
• Respirable Crystalline Silica Air Monitoring: General Industry OSHA's general industry silica standard has no Table 1 shortcut. See the exposure limits, how we sample, and what your monitoring results require.
• Solvent and VOC Air Monitoring: Toluene, Xylene and MEK Air monitoring for toluene, xylene, MEK and benzene. See the exposure limits, the right sampling media for each solvent, and what your results require.
• Welding Fume Air Monitoring and Exposure Assessment Welding fume is a mixture of metals and gases. See what is in it, the manganese PEL and TLV gap, how we sample, and why welders are rarely one exposure group.