PTM600S-AQI Portable Air Quality Monitor

A field case from the company's own reporting runs the PTM600S-AQI on mobile monitoring at a bauxite mine in Guinea, measuring gases, particulate matter and meteorological parameters together — the combination that lets a team separate what a site emits from what the weather brings in.

Why portable air monitoring

Many air questions are temporary: a dust complaint during one construction phase, odour episodes under one wind direction, a baseline survey before a plant expansion. A portable multi-parameter monitor answers them at a fraction of a fixed network's cost and timeline, and its data decides whether a permanent station is justified.

Because gases, particulates and weather are measured together, episodes can be correlated with wind direction and speed on the spot instead of being reconstructed later from separate instruments.

Planning a campaign

Tell us the parameters that matter, the campaign length and how the data will be used — screening, baseline or dispute evidence. Configuration, logging interval and any telemetry options follow from those answers, and the related fixed-station page shows the upgrade path when a campaign turns permanent.

Index stations versus reference stations

The PTM600S serves the index tier of air-quality networks: AQI-category monitoring for districts, campuses, industrial parks and city programmes that need defensible public numbers at many points rather than reference-grade numbers at few. The specification question is honesty about tier: index stations guide public communication and local management; they complement rather than replace the reference network. Buyers who state the tier plainly get networks that are judged on the right criteria — uptime, plausibility, coverage — instead of failing comparisons they were never priced for.

Siting decides an index station's value more than its sensor count. Representative breathing-height placement away from single-source dominance, honest documentation of nearby influences, and co-location checks against a reference instrument at commissioning turn a sensor box into a station. The multi-parameter set — the five gases plus both particulate fractions — exists so that the index is complete from one address: one power feed, one data path, one maintenance visit.

Data completeness as a design target

Public indices are judged on continuity: a station that vanishes during a pollution episode has failed at the only moment that mattered. Design for completeness — power resilience, telemetry buffering that backfills after outages, remote health signals that dispatch maintenance before the public notices a gap. The instrument's data storage and control interfaces support that design; the operating organisation completes it.

From raw counts to a public index

Between the sensor and the published index sits a chain of decisions the public never sees and the operator must be able to defend: averaging periods per pollutant, the index breakpoints that translate concentrations into categories, the completeness rules that decide whether an hour or a day counts, and the quality flags that quarantine suspect data without deleting it. The PTM600S supplies the chain's first link — continuous, timestamped, multi-parameter measurement — and the specification should name the rest of the chain at procurement: which software computes the index, whose breakpoint table applies, where the raw archive lives. An index whose chain cannot be drawn is a number waiting for its first hostile question.

Communication design matters as much as metrology at this tier: the public reads categories and colours, not concentrations, so the station's data must survive translation into both without distortion. Operators should test the translation with real episodes from the commissioning period — a dust event, a traffic peak — and confirm that what the index said matches what the raw data said, because the first controversy will arrive with the first bad-air week, not at leisure.

Network economics: many good stations

Index networks live on a trade: reference-grade certainty at a few points, or good certainty at many. The mathematics of exposure and of source-finding both favour density once a quality floor is held — hotspots hide between sparse stations, and population exposure is a spatial integral. The floor is the discipline: siting honestly, calibrating on schedule, flagging failures loudly, and publishing completeness with the data. A network run that way earns the right to its density; a network run as decoration earns the scepticism it receives, and the difference is visible in the operating budget long before it is visible in the data.

Glossary for AQI monitoring

Air Quality Index — the translation of several pollutants' concentrations into one public category through per-pollutant breakpoints. Sub-index — each pollutant's individual contribution, the largest of which sets the headline figure. Breakpoint — the concentration at which a pollutant's category changes, set by the governing regime. Averaging period — the window (hour, day) over which a concentration is computed before it meets its breakpoint. Nowcast — the weighted recent-hours calculation that lets an hourly index speak about a day-scale standard. Data completeness — the fraction of expected data actually delivered, published beside honest indices.

Optical particle sensing — the light-scattering measurement most index-tier particulate channels use, humidity-corrected in competent designs. Beta attenuation — the reference-tier particle method against which optical channels are compared. Sensor drift — the low-cost channel's slow wander, managed by network-level comparison against reference neighbours. Co-location period — the commissioning weeks an index station spends beside a reference instrument, earning its correction factors. Public dashboard — the display layer where categories and colours must not distort what the data said. Episode — the multi-hour pollution event during which an index network earns its entire budget.

Siting an index station: a worked pattern

The pattern, compressed: choose the population or park the index must represent; walk the candidate sites with the obstruction survey in hand, rejecting the kerbside that would speak only for traffic and the rooftop that would speak only for the wind; co-locate with a reference instrument for the commissioning weeks and publish the comparison; set the completeness target and the maintenance rhythm that can hold it; and only then fix the station. Each step is cheaper than the regret it prevents, and the dossier they form is the index's licence when the first controversial week arrives and the public asks, reasonably, why this box speaks for their air.

The index and the school run

An AQI station's most demanding audience is not the regulator but the parent deciding about the school run, the asthmatic checking the afternoon, the journalist on the first smog day of winter. Those readers need the index to be honest in a particular way: current, local, and explained in the words of health rather than of chemistry. Operators serve them by keeping the station's data flowing during episodes (when every instinct and every statistic matters most), by publishing the completeness beside the colour, and by resisting the temptation to smooth an ugly day. Trust in an index is a public asset accumulated in boring months and spent in bad ones; the station's maintenance calendar is, quite literally, a trust fund.

The station's founding dossier

Gather the index station's papers into one founding dossier while the knowledge is warm: the siting rationale with its photographs and obstruction survey, the co-location results and the correction factors they earned, the breakpoint table and software version that compute the index, the completeness target and the maintenance rhythm sworn to hold it, and the names of the humans accountable for each. The dossier is the station's answer to the only question that matters in its first controversy — why should this number be believed — and like all such answers it is cheap exactly once: at the founding.

Measurement

Parameter groups

Gases, particulate matter, meteorological parameters

Role

Mobile / temporary-campaign monitoring

Field case

Bauxite mine mobile monitoring, Guinea (company case report)

• Gas, particulate and weather measurement in one portable unit
• Suited to complaint response, baselines and boundary surveys
• Field-proven role in mine-site mobile monitoring